Dairy Establishment Inspection Manual – Chapter 18

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Table of Contents

Introduction and Use of Test Procedures

The critical processes (e.g. HTST, Batch pasteurizer, APPS and HHST) within an establishment must be tested in accordance with the test procedures found in this chapter. This testing can be done by trained plant personnel or a reliable third party.

The results of the testing should be recorded on the CFIA test procedures form (Appendix 18 - 2).

Plant management is responsible to ensure these test procedures are followed. They must review the results on a timely basis to ensure accuracy of testing and that corrective action was taken both on the equipment and on the product, if necessary.

Task 1.10.03.05 (Chapter 10 of the DEIM manual) Critical Process Test Procedures (found within the Equipment Program) defines the criteria required in the establishment's written program for the testing of the critical process equipment and controls. The establishment's written procedure must outline what tests are being performed, frequency, who is responsible, verification procedures, corrective action and records kept.

It is critical that any time there are alterations or new installations to the critical processes, equipment tests must be performed to evaluate the effectiveness of the changes and the impact on the system. For example changes required as a result of updates to the DEIM manual, i.e. addition of a control mechanism in the cooling section, installation of proximity switch, new task 1.11.19.02 (Chapter 11: Supplementary Milk Solids/Milk Fat Injections System), etc. will result in re-evaluating the system.

Appendix 19 - 6 of Chapter 19 (Minimum Frequency for Critical Process Equipment and Controls Tests) is a summary of the tests required, listed by DEIM task number, requirements to be met, test number and frequency of testing. For some tasks in the chart there are no test numbers listed. In these cases, even when there is no test number indicated, the task still must be tested as per the frequency stated.

A. Thermometers

Test 1: Indicating Thermometers - Temperature Accuracy

Application:

Pasteurization and airspace indicating thermometers. Applies to HTST, Batch, APPS and HHST systems.

Frequency:

  1. Upon installation and once every 6 months thereafter.
  2. Whenever the seal on a digital sensor or a digital control box has been broken and the reason for the breaking of the seal may have an effect on the sensing element. All incidences of a broken seal must be recorded in the log book of seal control and replacement or as noted by the equipment calibrator.

Criteria:

  1. Pasteurization indicating thermometer: accuracy within 0.25°C (0.5°F) in a specified scale range.
  2. Airspace indicating thermometer: accuracy within 0.5°C (1°F) in a specified scale range.

Apparatus:

  1. A certified test thermometer meeting the specifications of Appendix 18 - 1 - Testing Apparatus Specifications.
  2. Water, oil or other suitable media and agitator.
  3. Suitable means of heating water, oil or other suitable media bath.
  4. Indicating thermometer to be tested.

Method:

Both the indicating and test thermometers are exposed to water, oil or other suitable media bath of uniform temperature. Indicating thermometer reading is compared to the reading of the test thermometer.

Procedure:

  1. Bring up the water, oil or other suitable media bath temperature to within a range of 2°C of the appropriate pasteurization (diversion) temperature, airspace temperature or aseptic processing temperature.
  2. Maintain rapid agitation throughout the test.
  3. Insert the indicating and test thermometer to indicated immersion point during the test. Hold the indicating and certified thermometer for five minutes, two minutes for electronic recording thermometers, before reading.
  4. Compare both thermometer readings at the temperature reading within the test range and record results and thermometer identification.
  5. Repeat the test 3 times.
  6. Record the results.

Corrective Action:

Do not run test if mercury column has been split or capillary tube is broken, as thermometer should be returned to the factory for repair. When the indicating thermometer differs from the test thermometer by more than 0.25°C (0.5°F) and the airspace thermometer by more than 0.5°C (1°F), the scale plate of the indicating thermometer should be adjusted to agree with the test thermometer. Retest the thermometer after adjustment.

Note: The above procedure applies only to thermometers used for pasteurization. All other thermometers used in the establishment should be calibrated according to the manufacturer's recommendations.

Test 2:  Indicating Thermometers - Thermometric Response

Application:

Pasteurization indicating thermometer. Applies to HTST systems.

Frequency:

Upon installation and once every 6 months thereafter.

Criteria:

Indicating thermometer moves through a 7°C (12°F) range in no more than four (4) seconds.

Apparatus:

  1. Test thermometer.
  2. Stopwatch.
  3. Water, oil or other suitable media bath and agitator.
  4. Suitable means for heating the water, oil or other suitable media bath.
  5. Indicating thermometer from pasteurizer.
  6. Bucket of ice water

Method:

Measure the time required for the reading of the thermometer being tested to increase 7°C (12°F) through a specified temperature range (temperature range must include pasteurization or treatment temperature). The temperature used in the water, oil or other suitable media bath will depend upon the scale range of the thermometer to be tested.

Procedure:

  1. Immerse the indicating thermometer in water, oil or other suitable media bath held at a temperature at least 11°C (19°F) higher than the minimum scale reading on the indicating thermometer. The bath temperature should be higher than the maximum pasteurization temperature for which the thermometer is used.
  2. Immerse indicating thermometer in bucket of ice water for 10 seconds to cool it.
    Note: Continuous vigorous agitation of water, oil or other suitable media baths during the performance of steps 3, 4 and 5 is required. Elapsed time between end of step 1, and beginning of step 3 should not exceed 15 seconds so hot water does not cool significantly.
  3. Insert indicating thermometer in hot water, oil or other suitable media bath to proper bulb immersion depth.
  4. Start stopwatch when indicating thermometer reads 11°C (19°F) below bath temperature.
  5. Stop stopwatch when indicating thermometer reads 4°C (7°F) below bath temperature.
  6. Record the thermometric response time (must be less than 4 seconds).
  7. Repeat the test three times.
  8. Record the results.

    Example: For a thermometer used at pasteurization temperature set points of 71.7 and 74.4°C (161 and 166°F), a water, oil or other suitable media bath at a temperature of 78.3°C (173°F) could be used. 11°C (19°F) lower than 78.3°C (173°F) water, oil or other suitable media bath would be 67.3°C (154°F); 4°C (7°F) lower than 78.3°C (173°F) water, oil or other suitable media bath would be 74.3°C (166°F). Hence, after immersing the thermometer which has been previously cooled, in the 78.3°C bath (173°F), the stopwatch is started when thermometer reads 67.3°C (154°F) and stopped when it reads 74.3°C (166°F).

Note: The test included the pasteurization temperature of 71.7 and 74.4°C (161 and 166°F).

Corrective Action:

If the response time should exceed 4 seconds, the thermometer should be replaced or returned for repair.

Test 3:  Recording Thermometers - Check Against Indicating Thermometer

Application:

All recording and recording/controller thermometers used to record milk temperatures during pasteurization. Applies to HTST Batch, APPS and HHST systems.

Frequency:

Upon installation, once a year (6 months for APPS) and daily by the plant operator.

Criteria:

Recording thermometer shall not read higher than corresponding indicating thermometer.

Apparatus:

  1. Certified or calibrated indicating thermometer.
  2. Water, oil or other suitable media bath and agitator.
  3. Suitable means to heat the water, oil or other suitable media bath.

Method:

This test requires that a reading of the recording thermometer be compared with that of the indicating thermometer at a time when both are exposed to milk at a stabilized pasteurization temperature while the pasteurization system is operating and both thermometers are installed in their normal location in the temperature sensing chamber.

Procedure A: Annual Test

  1. Place the indicating or certified thermometer and recorder probe in a circulating water, oil or other suitable media bath at processing temperature. Stabilize for five minutes (two minutes for electronic recording thermometers).
  2. Read the indicating and recording thermometer. Record the results.
  3. Adjust the recording pen to the same as the indicating thermometer if needed.

Procedure B: Daily Test

  1. Read the indicating thermometer when the milk is at a stabilized temperature for 5 minutes (two minutes for electronic recording thermometers).
  2. Immediately inscribe a line using permanent ink on the recording thermometer chart that intersects the recording temperature arc at the pen location.
  3. Record on the chart the indicating thermometer temperature and initials of the operator or person performing the test.
  4. Record results and make adjustments if required.

Corrective Action:

If the mercury-activated thermometer or recorder-controller thermometer reads higher than the indicating thermometer, the pen or temperature adjusting mechanism should be adjusted. Re-test the thermometer after adjustment.

If the digital recording thermometer or recorder-controller thermometer reads higher than the indicating thermometer, the recording temperature arm should be adjusted to agree with the indicating thermometer if the recorder-controller arm is equipped with an adjustment. Re-test the thermometer after adjustment.

In cases where the recorder-controller thermometer arm cannot be adjusted (i.e. the recorder chart is digitally transcribed and there is no recorder arm), then the recording thermometer would need to be re-calibrated and adjusted using Procedure A. The details of the recorder-controller deviation and the corrective action must be documented.

Note: The above procedure applies only to recording thermometers used for pasteurization. All other recording thermometers used in the establishment should be calibrated according to the manufacturer's recommendations.

Test 4: Recording Thermometer - Time Accuracy

Application:

All recording and recorder/controller thermometers used to record time of pasteurization. Applies to HTST, Batch, APPS and HHST systems.

Frequency:

Upon installation and at least once a year (6 months for APPS) thereafter.

Criteria:

The recorded time of pasteurization shall not exceed true elapsed time.

Apparatus:

Stopwatch.

Method:

Comparison of the recorded time over a period of not less than 30 minutes with a stopwatch of known accuracy. For recorders utilizing electric clocks, check cycle on face plate of clock with known cycle; observe that clock is in operating condition.

Procedure:

  1. Determine if chart is appropriate to recorder. Verify that mechanism to grip and perforate chart paper is operational.
  2. Mark a reference point on the backplate of the recorder at the outer circumference of the chart paper.
  3. With the chart paper removed from the recorder, inscribe a reference mark at the outer edge of the chart, lined up with any printed hour time line.
  4. Install chart in the recorder with reference mark on chart lined up exactly with reference mark on back plate. Secure in place.
  5. Start stopwatch.
  6. At the end of 30 minutes by stopwatch, inscribe a second reference mark on the chart paper exactly opposite the backplate reference mark.
  7. Stop the stopwatch.
  8. Compare the time recorded on the chart with the true elapsed time from the stopwatch.
  9. For electric clocks, remove face plate; compare cycle specification on face plate with current cycle utilized.
  10. Enter finding on chart and initial.
  11. Record results.

Corrective Action:

If recorded time is incorrect the clock should be adjusted or repaired.

Note: The above procedure applies only to recording thermometers used for pasteurization. All other recording thermometers used in the establishment should be tested according to the manufacturer's recommendations.

Test 5: Recording Thermometer - Temperature Accuracy

Application:

All recording and recorder/controller thermometers used to record milk temperatures during pasteurization. Applies to HTST, Batch, APPS and HHST systems

Frequency:

Upon installation, at least once a year (6 months for APPS) and whenever recording pen-arm setting requires frequent adjustment.

Criteria:

Accuracy within ±0.5°C (1°F), in specified scale range. Batch pasteurizers used solely for thirty (30) minute pasteurization of milk or milk products at processing temperatures above 71°C, the recording thermometers shall be accurate to within ±1°C (±2°F).

Apparatus:

  1. Verified pasteurizer indicating thermometer.
  2. Three water, oil or other suitable media baths and agitator.
  3. Suitable means for heating the water, oil or other suitable media bath.
  4. Ice.

Method:

The testing of a recording thermometer for temperature accuracy involves the determination of whether or not the temperature pen-arm will return to within 0.5°C (1°F) or within 1°C (2°F) as provided above, of its previous setting after exposure to boiling water and melting ice.

Procedure:

  1. Heat a container of water to pasteurization temperature.
  2. Adjust the recording pen to read exactly as the previously tested indicating thermometer after a stabilization period of 5 minutes (2 minutes for electronic recording thermometers) at pasteurization temperature. The water, oil or other suitable media shall be rapidly agitated throughout the stabilization period.
  3. Prepare one water, oil or other suitable media bath by heating to the boiling point. Maintain temperature. Prepare a second bath with melting ice. Place baths within working distance of the recorder sensing element.
  4. Immerse the sensing element of recorder in boiling water, oil or other suitable media for not less than 5 minutes (2 minutes for electronic recording thermometers)
  5. Remove the sensing element from the boiling water, oil or other suitable media and immerse it in the water, oil or other suitable media heated to pasteurization temperature. Allow a 5 minute (2 minutes for electronic recording thermometers) stabilization period for both indicating or certified and recording thermometers. The two readings must be within ±0.5°C (1°F) or ±1°C (2°F) as provided above. The water, oil or other suitable media shall be rapidly agitated throughout the stabilization period.
  6. Remove sensing element from the bath at operating temperatures and immerse in melting ice for not less than 5 minutes (2 minutes for electronic recording thermometers).
  7. Remove sensing element from ice water and immerse in water at pasteurization temperature. Allow 5 minute (2 minutes for electronic recording thermometers) stabilization period for both indicating or certified and recording thermometers. The two readings must be within ±0.5°C (1°F) or ±1°C (2°F) as provided above. The water, oil or other suitable media bath shall be rapidly agitated throughout the stabilization period.
  8. Record results.

Corrective Action:

If the recording pen does not return to ±0.5°C (1°F) or ±1°C (2°F) as provided above, of indicating thermometer reading, the recording thermometer should be repaired or replaced as necessary.

Note: The above procedure applies only to recording thermometers used for pasteurization. All other recording thermometers used in the establishment should be tested according to the manufacturer's recommendations.

Test 6: Milk-Flow Controls - Milk Temperatures at Cut-In and Cut-Out

(A) Installation and Inspection Test

Application:

All Safety Thermal Limit Recorders used in connection with HTST pasteurizers.

Frequency:

Upon installation and once every 6 months there after and whenever the seal on the sensing element of the recorder-controller is broken and the reason for the breaking of the seal may have an effect on the sensing element. All incidences of a broken seal must be recorded in the log book of seal control and replacement or as noted by the equipment calibrator.

Criteria:
  1. No forward flow until pasteurization temperature has been reached.
  2. Flow diverted before temperature drops below minimum pasteurization temperature.
  3. Cut-in temperature is higher than cut-out temperature.
Apparatus:
  1. Water bath.
  2. Indicating or Certified test thermometer with accuracy of ±0.1°C (0.2°F) as determined by the National Bureau of Standards.
  3. Water bottle.
Method:

Observe the actual temperature of the indicating thermometer at the instant forward flow starts (cut-in) and stops (cut-out).

Procedure:
1. Cut-in temperature
  1. While water in water bath is completely flooding the sensing element of the Safety Thermal Limit Recorder and the indicating or certified thermometer, increase the heat gradually so as to raise the temperature of the water or milk at a rate not exceeding 0.5°C (1°F) every 30 seconds.
  2. Observe the verified indicating or certified thermometer reading at the instant the Flow Diversion Device starts to move.
  3. Observe that the frequency pen reading is synchronized with the recording pen on the same reference arc.
  4. Record the indicating or certified thermometer reading.
2. Cut-out temperature
  1. After the cut-in temperature has been determined and while the water is above the cut-in temperature, allow the water to cool slowly at a rate not exceeding 0.5°C (1°F) per 30 seconds. Cool water in a water bottle may be used if necessary.
  2. Observe indicating or certified thermometer reading at the instant forward flow stops.
  3. Record the indicating or certified thermometer reading.

(B) Daily Test

Application:

All Safety Thermal Limit Recorders used in connection with HTST pasteurizers.

Frequency:

Daily by the plant operator, whenever a new set-point is selected on a multiple temperature divert unit and whenever the seal on the recorder/controller is broken. All incidences of a broken seal must be recorded in the log book of seal control and replacement or as noted by the equipment calibrator.

Criteria:
  1. No forward flow until pasteurization temperature has been reached.
  2. Flow is diverted before temperature drops below minimum pasteurization temperature.
  3. Cut-in temperature is higher than cut-out temperature.
Apparatus:

None.

Method:

Observe the actual temperature of the indicating thermometer at the instant forward flow starts (cut-in) and stops (cut-out).

Procedure:
1. Cut-in temperature
  1. With the system operating and while milk or water is completely flooding the sensing element of the Safety Thermal Limit Recorder and the indicating thermometer within the sensing chamber, increase the heat gradually so as to raise the temperature of the water or milk at a rate not exceeding 0.5°C (1°F) every 30 seconds.
  2. Observe the indicating thermometer reading at the instant the Flow Diversion Device begins to move.
  3. Observe that the frequency pen reading is synchronized with the recording pen on the same reference arc.
  4. Record the indicating thermometer reading on the recorder chart; inscribe initials.
2. Cut-out temperature
  1. After the cut-in temperature has been determined and while the milk or water is above the cut-in temperature, allow the milk or water to cool slowly at a rate not exceeding 0.5°C (1°F) per 30 seconds.
  2. Observe indicating thermometer reading at the instant forward flow stops.
  3. Record the indicating thermometer reading on the recorder chart; inscribe initials.
Corrective Action:

If the reading is below the minimum pasteurization temperature, the cut-in and cut-out mechanism and/or the differential temperature mechanism should be adjusted to obtain proper cut-in and cut-out temperatures by repeated tests.

Test 6.1: Milk-Flow Controls - Milk Temperatures - Cut-In and Cut-Out HHST Pasteurizers and APPS Using Indirect Heating

Application:

All HHST pas­teuriz­ers and APPS using indirect heating. When testing aseptic processing systems, the "product divert system" or product divert valve or acceptable control system may be substituted for the flow diversion device when it is referenced in this test.

Frequency:

Upon installation, and every 6 months there after and whenever the thermal controller seal is broken and the reason for the breaking of the seal may have an effect on the sensing element. All incidences of a broken seal must be recorded in the log book of seal control and replacement or as noted by the equipment calibrator.

Criteria:
  1. No forward flow unless pasteurization or aseptic processing temperature has been achieved.
  2. Product flow diverted at a temperature lower than the chosen pasteurization or aseptic processing standard (i.e. that which is established by the scheduled process, where Fo=3.0 as a minimum).
Apparatus:

Oil bath (above boiling point).

Method:

Observe the actual temperature in the constant temperature bath at which the two sensing elements (holding tube and flow diversion device) signal for forward flow (cut-in) and diverted flow (cut-out).

Procedure:
1. Cut-in temperature
  1. Wire the test lamp in series with the control contacts of the sensing element (holding tube). Immerse this sensing element in the constant temp­erature bath. Raise the bath temperature at a rate not exceeding 0.5°C (1°F) every 30 seconds.
  2. Observe the temperature reading at the cut-in temperature (when the test lamp lights).
  3. Record the temperature.
  4. Repeat the procedure for the other sensing element, i.e. the flow-diversion device.
2. Cut-out temperature
  1. After the cut-in tempera­ture has been determined and while the oil is above the cut-in temperature, allow the oil to cool slowly at a rate not exceeding 0.5°C (1°F) per 30 seconds.
  2. Observe the temperature reading on the controller when the test lamp goes out (cut-out temperature).
  3. Determine that the cut-out temperature on the thermal limit controller is equivalent to or above the chosen pasteurization or aseptic processing standard (i.e. that which is established by the scheduled process, where Fo= 3.0 as a minimum).
  4. Record the temperature.
  5. Repeat the procedure above for the other sensing element, i.e., the flow diversion device.
  6. When proper cut-out tempera­ture has been verified for both sensing elements, seal the controller system.
Corrective action:

Where adjustment is necessary, refer to manufacturer's instructions. After adjust­ment, repeat the procedure above.

Test 6.2: Milk-Flow Controls - Milk Temperatures - Cut-In and Cut-Out HHST Pasteurizers and APPS Using Direct Heating

Application:

All HHST pas­teurizers and aseptic processing systems using direct contact heating. When testing aseptic processing systems, the "product divert system" or product divert valve" or "acceptable control system" may be substituted for the "flow-diversion device" when it is referenced in this test.

Frequency:

Upon installa­tion, and every 6 months there after; when­ever the thermal limit controller seal is broken.

Criteria:
  1. No forward flow unless pasteurization or aseptic processing temperature has been achieved.
  2. Product flow diverted at a temperature lower than the chosen pasteurization or aseptic processing standard (i.e. that which is established by the scheduled process, where Fo=3.0 as a minimum).
Apparatus:

Oil bath (above boiling point).

Method:

Ob­serve the actual temperature in the constant temperature bath at which the two sensing elements (holding tube and flow diversion device) signal for forward flow (cut-in) and diverted flow (cut-out).

Procedure:
1. Cut-in temperature
  1. Wire the test lamp in series with the control contacts of the sensing element (holding tube). Immerse this sensing element in the constant temp­erature bath. Raise the bath temperature at a rate not exceeding 0.5°C (1°F) every 30 seconds.
  2. Observe the temperature reading on the controller when the test lamp lights (cut-in temperature).
  3. Record the temperature.
  4. Repeat the procedure for the other two sensing elements, i.e. the vacuum chamber and the flow diversion device.
2. Cut-out temperature
  1. After the cut-in tempera­ture has been determined and while the oil is above the cut-in temperature, allow the oil to cool slowly at a rate not exceeding 0.5°C (1°F) per 30 seconds.
  2. Observe the temperature reading on the controller when the test lamp goes out (cut-out temperature).
  3. Determine that the cut-out temperature on the thermal limit controller is above the chosen pasteurization or aseptic processing standard (i.e. that which is established by the scheduled process, where Fo=3.0 as a minimum).
  4. Record the temperature.
  5. Repeat the procedure for the other two sensing elements, i.e. the infusion chamber and the flow diversion device.
  6. Rewire the test lamp in series with the control contacts from each sensing element, respectively.
  7. When proper cut-out tempera­ture has been verified for both sensing elements, seal the controller system.
Corrective action:

Where adjustment is necessary, refer to manufacturer's instructions. After adjust­ment, repeat the procedure above.

Test 7: Safety Thermal Limit Recorder - Thermometric Response

Application:

All Safety Thermal Limit Recorders used in connection with HTST pasteurizers.

Frequency:

Upon installation and at least once a year there after.

Criteria:

Recorder-Controller moves through a specific range 7°C (12°F) in less than five (5) seconds.

Apparatus:

  1. Verified indicating thermometer.
  2. Stopwatch.
  3. Water baths and agitator.
  4. Suitable means for heating the water bath.

Method:

Measure the time interval between the instant when the recording thermometer reads 7°C (12°F) below the cut-in temperature and the moment of cut-in by the controller. This measurement is made when the sensing element is immersed in a rapidly agitated water bath maintained at exactly 4°C (7°F) above the cut-in temperature.

Procedure:

  1. Check and, if necessary, adjust the pen-arm setting of the recording thermometer to be in the proper reference arc, and to agree with the indicating thermometer reading at pasteurization temperature.
  2. Determine the cut-in temperature of controller (Test 6).
  3. Remove the sensing element and allow it to cool at room temperature.
  4. Heat the water bath to exactly 4°C (7°F) above the cut-in temperature while vigorously agitating bath to insure uniform temperature.
  5. Immerse Safety Thermal Limit Recorder bulb in bath. Continue vigorous agitation during 6 and 7 below.
  6. Start stopwatch when the recording thermometer reaches a temperature of 7°C (12°F) below the cut-in temperature.
  7. Stop stopwatch when the Flow Diversion Device begins to move.
  8. Record results.

Corrective Action:

If the response time should exceed 5 seconds, the Safety Thermal Limit Recorder should be repaired.

B. Holding Time

Test 8: Salt Conductivity Test (Procedure Under Review)

Application:

To all HTST pasteurizers employing a holding time of fifteen (15) seconds or longer.

Note: Certain regulatory agencies may grant an individual plant permission to use a shorter hold time in conjunction with a required higher pasteurization temperature, or permission to use a lower pasteurization temperature in conjunction with a longer required hold time. In these cases the specified alternate hold time is substituted in place of fifteen (15) seconds.

Frequency:

  1. Upon installation and annually thereafter.
  2. Whenever seal on speed setting is broken.
  3. Whenever any alteration is made affecting the holding time, the velocity of the flow (such as replacement of pump, motor, belt, driver or driven pulleys, or decrease in number of HTST plates), or the capacity of holding tube.
  4. Whenever a check of the capacity indicates a speed up.

Criteria:

Every particle of milk shall be held for the minimum legal hold time at least fifteen (15) seconds in both the forward and diverted flow positions.

Apparatus:

  1. Electrical conductivity measuring device.
  2. Table salt (sodium chloride).
  3. Device used for injecting brine into the holding tube.
  4. Stopwatch.
  5. 36 litre (8 gallon) can.
  6. Wrenches.

Method:

The holding time is determined by timing the interval for an added trace substance to pass through the holder. Although the time interval of the fastest particle of milk is desired, the conductivity test is made with water. The results found with water are converted to the milk flow time by formulation since a pump may not deliver the same amount of milk as it does water. See test 9 for the calculated method.

Procedure A: For systems with a positive displacement pump used as the Flow Control Device.

  1. Examine the entire system to insure that all flow promoting equipment is operating at maximum capacity and all flow impeding equipment is so adjusted or bypassed as to provide minimum resistance to the flow. There shall be no leakage on the suction side of the timing pump.
  2. Adjust variable speed pump to its maximum capacity (preferably with a new belt and full size impellers).
  3. Check homogenizers for seals and/or gears or pulley identification.
  4. Install one electrode at the inlet (lowest point) to the holding tube and the other electrode at the holding tube outlet. Close the circuit to the electrode located at the holding tube inlet.
  5. Operate the pasteurizer using water at pasteurization temperature, with flow diversion device in forward flow position.
  6. Quickly inject saturated sodium chloride solution (approximately 50 mL) into the holding tube inlet.
  7. Start the stopwatch with the first movement of the indicator of a change in conductivity. Open the circuit to the inlet electrode and close the circuit to the electrode at the holding tube outlet.
  8. Stop the stopwatch with the first movement of the indicator of a change in conductivity.
  9. Record the holding time.
  10. Repeat the test six or more times, until successive results are within 0.5 seconds of each other. The average of these tests is the holding time for water in forward flow. When consistent results cannot be obtained, purge the equipment, check instruments and connections, and check for air leakage on suction side. Repeat tests. Should consistent readings not be obtained, use the fastest time as the holding time for water.
  11. Repeat steps (4) through (10) for the holding time in diverted flow.
  12. With the pump at the same speed and equipment adjusted as in (1) above, time the filling of a 36 litre (8 gallon) can with a measured weight of water using the discharge outlet with the same head pressure as in normal operation. Average the time of several trials. (Since flow rates of the large capacity units make it very difficult to check by filling a 36 litre can, it is suggested that a magnetic flow meter be hooked up into the system or a calibrated tank of considerable size be used).
  13. Repeat procedure (12) using milk or the dairy products to be pasteurized through this unit.
  14. Compute the holding time for milk from the following formula by weight, using the average specific gravity. Compute separately for forward flow and diverted flow.

    Holding time for milk = (1.032(TMw)/Ww) (by weight), in which:

    • 1.032 = specific gravity for milk.
    • T = average holding time for water.
    • Mw  = average time required to deliver a measured weight of product.
    • Ww  = average time required to deliver an equal weight of water.
    • The holding time for milk may also be computed from the following formula by volume. Compute separately for forward flow and diverted flow.

    Holding time for milk = T(Mv)/Wv) (by volume), in which:

    • T = average holding time for water.
    • Mv  = average time required to deliver a measured volume of product.
    • Wv  = average time required to deliver an equal volume of water.
  15. Record results.
Corrective Action:

When the computed holding time for milk is less than that required, either in forward flow or diverted flow, the speed of the flow control device shall be reduced or an adjustment made in the holding tube and the timing test repeated until satisfactory holding time is achieved. Should an orifice be used, to correct the holding time in diverted flow, there should be no excessive pressure exerted on the underside of the valve seat of the flow-diversion device.

Procedure B: For systems with a Magnetic Flow Meter System used as a Flow Control Device.

  1. Examine the entire system to insure that all flow promoting equipment is operating at maximum capacity and all flow impeding equipment is so adjusted or bypassed as to provide minimum resistance to the flow.
  2. Adjust the set point on the flow alarm to its highest possible setting.
  3. Adjust the set point on the flow controller to a flow rate estimated to yield an acceptable holding time.
  4. Install one electrode at the inlet (lowest point) to the holding tube and the other electrode at the holding tube outlet. Close the circuit to the electrode located at the holding tube inlet.
  5. Operate the pasteurizer using water at pasteurization temperature, with Flow Diversion Device in forward flow position.
  6. Quickly inject saturated sodium chloride solution (approximately 50 mL) into the holding tube inlet.
  7. Start the stopwatch with the first movement of the indicator of a change in conductivity. Open the circuit to the inlet electrode and close the circuit to the electrode at the holding tube outlet.
  8. Stop the stopwatch with the first movement of the indicator of a change in conductivity.
  9. Record the holding time.
  10. Repeat the test six (6) or more times, until six (6) successive results are within 0.5 seconds of each other. The average of these six (6) tests is the holding time for water in forward flow. When consistent results cannot be obtained, purge the equipment, check instruments and connections, and check for air leakage on suction side of the pump, located at the raw product supply tank. Repeat tests. If six (6) consecutive readings cannot be achieved within 0.5 seconds, the pasteurizing system is need of repair.
  11. With the flow controller at the same set point as in (3) above, time the filling of a 36 litre (8 gallon) can with a measured weight of water using the discharge outlet with the same head pressure as in normal operation. Average the time of several trials. (Since flow rates of the large capacity units make it very difficult to check by filling a 36 litre can, it is suggested that a magnetic flow meter be hooked up into the system or a calibrated tank of considerable size be used).
  12. Record results.
Corrective Action:

When the computed holding time for milk is less than that required the set point on the Flow Controller shall be decreased, or adjustment made in the holding tube and the timing test repeated until a satisfactory holding time is achieved. Should an orifice be used, to correct the holding time in diverted flow, there should be no excessive pressure exerted on the underside of the valve seat of the flow diversion device.

Test 9: Calculated Method (Procedure Under Review)

Application:

To all HTST pasteurizers employing a holding time of 15 seconds or longer.

Frequency:

  1. Upon installation and annually thereafter;
  2. Whenever seal on speed setting is broken;
  3. Whenever any alteration is made affecting the holding time, the velocity of the flow (such as replacement of pump, motor, belt, driver or driven pulleys, or decrease in number of HTST plates), or the capacity of holding tube;
  4. Whenever a check of the capacity indicates a speed up.

Criteria:

Every particle of milk shall be held for the minimum legal hold time in both the forward and diverted flow positions.

Apparatus:

Tape Measure.

Method:

Determine the efficiency factor using the Reynolds number for water and all products to be processed at the maximum flow rate. Also determine flow rate ratio (product:water). Use the smallest efficiency factor and the determined flow rate ratio to calculate the required holding tube length.

Procedure:

  1. Determine the inside diameter in metres of the holding tube (Table 1).
  2. Calculate the velocity of the product using the following equation:
    • V = F/A
    • Where: V = Velocity (m/s).
    • F = Flow rate (litres/hr or litres/sec or m3/s).
    • A = Area (m2)Footnote 3
Table 1 - Holding Tube Dimensions
Outside Diameter Inside Diameter (d)Table note 1 Area (a) Volume (q)
in. cm in. ft cm ft2 cm2 Imp. gal./ft Table note 2 l/m
1 2.54 0.902 0.0752 2.291 0.0044 4.122 0.0277 0.4122
1.5 3.81 1.402 0.117 3.561 0.0107 9.959 0.0669 0.9959
2 5.08 1.87 0.156 4.749 0.0191 17.713 0.1190 1.7713
2.5 6.35 2.37 0.198 6.019 0.0306 28.454 0.1912 2.8454
3 7.62 2.87 0.239 7.289 0.0449 41.728 0.2803 4.1728
4 10.16 3.834 0.32 9.739 0.0802 74.494 0.5003 7.4 494

Table notes

Table note 1

"Fundamentals of Food Process Engineering – 3rd Edition", Romeo T. Toledo, Department of Food Science and Technology, University of Georgia, Athens, Georgia, 2007.

Return to table note 1 referrer

Table note 2

1 imp. gal. = 0.16026 ft3

Return to table note 2 referrer

Note: Holding tube dimensions: 1" & 1½" is 18 standard wire gauge (SWG), 2", 2½" & 3" is 16 SWG, 4" is 14 SWG.

Table 2 - Density and Viscosity Values
Product Density (p) Viscosity (μ)
Type Temp g/l lb/ft3 cP lb/ft×s
Milk 72°C 1012 63.15 0.515 0.000346
Cream (40%) 75°C 982.6 61.3 3.4 0.00228
Ice Cream Mix 80°C 1100 68.64 150 0.1008

Note: These figures incorporate a safety factor in recognition of the potential variances in product formulations and batching procedures.

3. Determine the Reynolds number at the maximum flow rate for water and all products to be processed using the following formula:

  • Reynolds number (Re) = (p x V x d)
  • Where: p = fluid density (kg/m3).
  • V = velocity (m/s)
  • d = tube inside diameter (m).
  • μ = viscosity (kg/ (sec x m)). (Table 2)

4. Convert the Reynolds number obtained into logarithmic number.

5. Using the converted Reynolds number read the efficiency factor from the provided chart (Figure 1).

6. Determine the flow rate ratio (r) using the method outlined in Test 8, steps 11 and 12 and the following formula:

  • Flow rate ratio (r) = ((Mv)/Wv)
  • Where: Mv = average time required to deliver a measured volume of product.
  • Wv = average time required to deliver an equal volume of water.
  • For large pasteurizers this should be done by using a magnetic flow meter instead of 36 litre can.

7. Calculate the minimum holding tube length using the following formula:

  • L = (t x V)/(E x r)
  • Where: L = Length (m)
  • t = minimum holding time (s).
  • V = velocity (m/s).
  • E = efficiency factor.
  • r = flow rate ratio

8. Calculate the target salt test using the following formula:

  • Target salt test in seconds = L/V
  • Where: L = Length (m).
  • V = velocity (m/s).

Example:

A cheese plant wants to process cheese milk at 162°F for 16 seconds at a flow rate of 25,000 litres per hour. The determined flow ratio of milk/water is 0.88. The holding tube size to be installed is 2". What is the required holding tube length and target salt test?

Figure 1 - Efficiency Values Ration of Average to Maximum Velocity (V/V Max)
Figure - Efficiency Values Ration of Average to Maximum Velocity (V/V Max). Description follows.
Description of image - Effect of Reynolds number on the ratio of average to maximum velocity in smooth tubes
  • This graph is used to determine the efficiency value by using the Reynolds number to calculate the time in smooth holding tubes.
  • The x axis on the graph shows Efficiency Value for the Ratio of Average to Maximum Velocity (V/V max). The values for the scale range from 0.5 to 1.0.
  • The y axis shows Reynolds No. - Log Chart. The values range from 102 to 107.
  • The graph also shows the points that the laminar flow, transitional and turbulent flow occur.

Convert the flow rate from litres per hour to litres per sec:

Flow rate = 25000/(3600) = 6.94 litres/sec

Convert the tube internal diameter from inches to metres:

Pipe diameter = 2"; therefore internal diameter from Table 1 = 1.872" = 0.0475 m

Calculate the cross-sectional area of the tube (internal):

Area = πr2 = 3.14 × (0.0475)/4 = 0.00177 m2

Using the flow rate and cross-sectional area, calculate the velocity:

  • Velocity = F/A; where F = flow rate and A = cross-sectional area;
  • Velocity = (6.94 × 0.001(m3/s)) /(0.00177(m2)) = 3.90 m/s

Calculate the Reynolds number for water and milk:

  • Re water = (p x V x d); where p = density; V = velocity; d = tube inside diameter; μ = viscosity of water;
  • Re water = (1000(kg/m3) × 3.90(m/s) × 0.0475(m))/0.0005(kg/sec×m)
  • = 370500 or 3.7 × 105
  • Using the calculated Reynolds number and Figure 1, the efficiency factor of water = 0.86
  • Re milk = (p x V x d)
  • = (1012(kg/m3) × 3.90(m/s) × 0.0475(m))/0.000515(kg/sec×m)
  • = 364025 or 3.6 × 105
  • Using the calculated Reynolds number and Figure 1, the efficiency factor of milk = 0.86
  • For holding tube length calculation use the lowest efficiency factor of the two = 0.86

Calculating the tube length:

  • Tube length = L = (t x V)/(E x r); where t = minimum holding time; V = velocity;
  • E = efficiency factor; r = flow rate ratio
  • Tube length = L = (16(s) × 3.90(m/s))/(0.86 × 0.88)
  • = 83.42 metres

Calculating the target salt test:

  • Target salt test = L/V; where L = length; V = velocity
  • = 83.42(m)/3.90(m/s)
  • = 21.39 seconds

References:

  1. A Research Note, Prediction Of Holding Times For Continuous Thermal Processing of Power-Law Fluids, Volume 41 (1976) Journal of Food Science, J.A. Palmer and V.A. Jones. Department of Food Science, North Carolina State University, Raleigh, NC 27607.
  2. Effect of Process Variables on the Holding Time in an Ultrahigh–Temperature Steam Injection System, Volume 53. No. 10 Journal of Dairy Science, E.R. Edgerton and V.A. Jones. Department of Food Science and J. A. Warren Department of Experimental Statistics, North Carolina State University, Raleigh 27607.

Test 9.1: Calculation of Holding Tube Length (Under Review)

Application:

To all APPS and HHST systems using direct and indirect heating.

Note: Because of the short holding times and holding tube length, the required minimum holding times for all APPS and HHST systems must be calculated from the pumping rate rather than the salt conductivity test. Laminar flow may occur in high viscosity products since the fastest particle can move at twice the speed of the average particle. Therefore, the holding tube lengths must be calculated as twice the length to compensate for laminar flow.

Frequency:
  1. Upon installation and annually thereafter.
  2. Whenever the seal on the speed setting is broken.
  3. Whenever any alteration is made affecting the holding time, the velocity of the flow (e.g. replacement of pump, motor, belt, driver or driven pulley, decrease in number of heat exchange plates), or the capacity of the holding tube.
  4. Whenever a check of the capacity indicated a speed up.
Criteria:

Every particle of product to be held for the minimum holding time in both forward and diverted flow positions.

Apparatus:

None.

Method:

The holding tube length is determined by calculation and is specified in the scheduled process. Fully developed laminar flow is assumed. An experimental determination of pumping rate is required, which is accomplished by determining the time required for the pasteurizer to fill a vessel of known volume, converting this by division to obtain flow rate in gallons per second and multiplying this by the applicable number from the tables below to obtain the required length of the holding tube. The resulting calculations will provide the required length of the holding tube for the process. Holding tube lengths for pasteurizers with indirect heating for a pumping rate of 1 gallon (4.546 L)/second are:

Table 1 - Holding Tube Lengths (Inches/cm) for Indirect Heating Pasteurizers
Holding Time
(SEC)
1" (2.54 cm) Tube Diameter " (3.81 cm) Tube Diameter 2" (5.08 cm) Tube diameter " (6.35 cm) Tube diameter 3" (7.62 cm) Tube diameter
1 723.0 (1836.42) 300.0 (762) 168.0 (426.72) 105.0 (266.7) 71.4 (181.36)
0.5 362.0 (919.48) 150.0 (381) 84.0 (213.36) 52.4 (133.10) 35.7 (90.67)
0.1 72.3 (183.64) 30.0 (76.2) 16.8 (42.67) 10.5 (26.67) 7.14 (18.14)
0.05 36.2 (91.95) 15.0 (38.1) 8.4 (21.34) 5.24 (13.31) 3.57 (9.07)
0.01 7.23 (18.36) 3.0 (7.62) 1.68 (4.27) 1.05 (2.67) 0.714 (1.814)

Assumed Pumping rate = 1 US Gal/Sec (4.546 Litres/Sec) (1 US Gal = 3.785 Litres)

Note: These lengths assume fully developed laminar flow

With steam injection processes, the holding tube is adjusted since the product volume increases because of increased volumes in the holding tube. With a 120°F (48.89°C) temperature increase by steam injection, a volume increase of 12% will occur in the holding tube. The values in the table below reflect this volume increase. This surplus water is evaporated off as the pasteurized product is cooled in the vacuum chamber. The temperature-time standard is chosen by the processor and the required holding tube length is calculated from an experimental determination of the pumping rate.

Table 2 - Holding Tube Lengths (inches /cm) for Steam Injection Pasteurizers
Holding Time
(SEC)
1" (2.54 cm) tube diameter " (3.81 cm) tube diameter 2" (5.08 cm) tube diameter " (6.35 cm) tube diameter 3" (7.62 cm) tube diameter
1 810 (2057.4) 336 (853.44) 188 (477.52) 118 (299.72) 80.0 (203.2)
0.5 405 (1028.7) 168 (426.72) 94.0 (238.76) 59.0 (149.86) 40.0 (101.6)
0.1 81.0 (205.74) 33.6 (85.34) 18.8 (47.75) 11.8 (29.97) 8.00 (20.32)
0.05 40.5 (102.87) 16.6 (42.16) 9.40 (23.87) 5.90 (14.99) 4.00 (10.16)
0.01 8.10 (20.57) 3.36 (8.53) 1.88 (4.78) 1.18 (3.0) .80 (2.03)

Assumed Pumping Rate = 1 US Gal/Sec (4.546 Litres/Sec) (1 US Gal = 3.785 Litres)

Note: These lengths assume fully developed laminar flow and temperature increase of 120°F (48.89°C) by steam injection.

The calculations follow the equation: A = B X C

Where:

  • A = holding tube length (inches)
  • B = measured pumping rate (gallons per second)
  • C = holding tube length from Table (inches per gallon per second)

Example 1:

The health authority knows the time-temperature standard and flow rate and wants to know the required length for the holding tube. The pasteurizer has a nominal capacity of 10,000 pounds per hour. The time required to fill a 10 gallon can with water from the pasteurizer is 32.5 seconds. The temperature-time standard is 204°F (95.56°C) for 0.05 second, and the holding tube is 2 inches in diameter. The pumping rate is 10 gallons divided by 32.5 seconds, which is 0.308 gallon per second.

The required holding tube length, A is calculated from Equation 1 (A = B X C). The pumping rate, B, is 0.308 gallon per second, and from Table 1, the holding tube length, C, required for a holding time of 0.05 second with a pumping rate of 1 gallon per second in 2 inch diameter tubing is 9.4 inches.

For this example,

A = 0.308 × 9.4
A = 2.9 inches
Therefore the holding tube must be at least 2.9 inches long.

Example 2:

The health authority knows the temperature-time standard and the actual holding tube length and wants to know the maximum permissible pumping rate.

The pasteurizer has a nominal capacity of 60,000 pounds per hour, and the temperature-time standard is 204°F (95.56°C) for 0.05 second. The holding tube is 3 inches in diameter and 6 inches long.

The pumping rate is calculated from Equation 1 (A = B X C). The holding tube length, A, is 6 inches and from Table 1, the holding tube length, C, required for a holding time of 0.05 second with a pumping rate of 1 gallon per second in 3 inch diameter tubing is 4 inches. For this example:

6 = B × 4
B = 6/4
Therefore … B = 1.5 gallons per second.

The maximum permissible pumping rate is 1.5 gallons per second. At this pumping rate, the time required to fill a 100 gallon vat is 100 gallons divided by 1.5 gallons per second, or 66.6 seconds.

Procedure:

  1. Examine the entire system to insure that all flow promoting equipment is operating at maximum capacity and all flow impeding equipment is so adjusted or bypassed as to provide minimum resistance to the flow. In-line filters must be removed, booster pumps must be in operation and vacuum equipment in the system must be operating at a maximum vacuum.
  2. Before beginning, the pasteurizer is to be operated at maximum flow for a sufficient time to purge air from the system (about 15 minutes) and tighten pipe connections on the suction side of the metering pump enough to exclude the entrance of air. With the pasteurizer operating on water, adjust the metering pump to its maximum capacity, preferably with a new belt and full-size impellers.
  3. Make sure no flow exists in the diverted line and measure the time required to deliver a known volume of water at the discharge line of the pasteurizer in forward flow. Repeat this at least once to determine that the measurements are consistent.
  4. Repeat the above steps 1 to 3 of this procedure in diverted flow by collecting the water at the discharge of the divert line.
  5. Select the greatest flow rate (shortest delivery time for the known volume) and calculate the flow rate in gallons per second by dividing the known volume by the time required to collect the known volume. Multiply this value by the appropriate number in the above tables (Table 1 for indirect heating and Table 2 for direct heating with steam injectors).
  6. Determine the number and type of fittings in the holding tube and convert these to equivalent lengths of straight pipe with the use of Table 3. Determine the total length of the holding tube by adding the equivalent lengths of the fittings to the measured lengths of straight pipe. If the actual holding tube length is equivalent to or greater than the required holding tube length, record the number and type of fittings, the number and length of straight pipes and the holding tube configuration. Make sure the holding tube slopes upward at least 6.35 mm (0.25 inch) per foot. If the temperature sensor is located at the beginning of the holding tube, the holding tube shall be protected against heat loss by material that is impervious to water.
  7. Re-seal regulatory controls as necessary.
  8. Record results.
Table 3: Centerline Distances of 3-Fittings
3 A - Fitting Size Designation 1 1½ 2 2½ 3
2C 90° bend 3.4 4.8 6.2 8 9.7
2CG 90° bend 3.1 4.5 5.8 7.6 9.3
2F 90° bend 3.4 4.8 6.2 8 9.7
2FG 90° bend 3.1 4.5 5.8 7.6 9.3
2E 90° bend 3.4 4.8 6.2 8 9.7
2EG 90° bend 3.2 4.6 6 7.7 9.4

Alternate procedure for pasteurizers of large capacity:

  1. Remove the divert line from the raw product supply tank and turn off the product pump feeding the raw product supply tank. Suspend a sanitary dip stick in the raw product supply tank and operate the pasteurizer at maximum capacity.
  2. Record the time required for the water level to move between two graduations on the dip stick. The volume of water is calculated from the dimensions of the raw product supply tank and the drop in water level.
  3. Flow rate = the volume of water removed from the raw product supply tank divided by the time required to remove the water.
Corrective Action:

If the length of the holding tube is shorter than the calculated length, reseal the metering pump at a slower speed or lengthen the holding tube or both and repeat the above determination.

C. Flow Diversion Device

Test 10: Leakage Past Valve Seat(s)

Application:

To all Flow Diversion Devices used with HTST pasteurizers and HHST systems which use a dual stem valve assembly.

Frequency:

Upon installation and at least once every 6 months thereafter.

Criteria:

Raw milk must not leak past the Flow Diversion Device into pasteurized milk channels.

Apparatus:

Suitable tools for disassembly of Flow Diversion Device and sanitary piping.

Method:

Observe the valve seat(s) of the Flow Diversion Device for leakage.

Procedure:

  1. While operating the system with water, place the Flow Diversion Device in the diverted flow position.
  2. Disconnect the forward flow piping of a single stem device and verify that the valve seat does not leak. On a dual stem device, remove the leak detect pipe or observe carefully through the sight glass.
  3. Check the leak escape ports of a single stem device to ensure that they are open.
  4. Record results.

Corrective Action:

If leakage is noted, device must be dismantled and defective gaskets replaced or other suitable repairs made.

Test 11: Operation of Valve Stem(s)

Application:

To all Flow Diversion Devices used with HTST pasteurizers where a stem packing nut is used.

Frequency:

Upon installation and at least once every 6 months thereafter.

Criteria:

The Flow Diversion Device valve stem(s) move(s) freely when the stuffing box nut is fully tightened.

Apparatus:

Suitable tools for disassembly of Flow Diversion Device and sanitary piping.

Method:

Observe Flow Diversion Device valve stem(s) for ease of movement.

Procedure:

  1. Tighten the stuffing box nut as much as possible.
  2. Operate the HTST and place the Flow Diversion Device in forward and diverted flow several times.
  3. Observe that the Flow Diversion Device valve stem(s) move(s) with ease.
  4. Record results.

Corrective Action:

If valve action is sluggish, suitable adjustment or repair shall be made to permit stem to act freely in all positions, with packing nut, when used fully tightened.

Figure 2 - Valve Body Sub Assembly
Figure - Valve Body Sub Assembly. Description follows.
Description of image - This diagram shows the parts of the Valve Body Sub-Assembly.

It consists of:

  • 4" nut
  • Leak Detector Spring
  • Leak Detector O-Ring
  • Leak Detector Poppet
  • Upper Valve Body
  • Paper Gasket
  • Plunger Nut
  • Small Rubber Ring (2 ⅛" outer diameter (O.D.))
  • Ring Separating Disc
  • Large Rubber Ring (3 ¾" O.D.)

Reference: Milk Pasteurization Controls and Tests (Red cow book), 8th Edition, 2003.

Test 12: Device Assembly, Single Stem Device

Application:

To all single stem Flow Diversion Devices used with HTST pasteurizers.

Frequency:

Upon installation, at least once every 6 months thereafter and whenever the microswitch is re-set or replaced.

Criteria:

The Flow Control Device and all other flow promoting devices located between the constant level tank and the vacuum breaker stop or are isolated from the system when the Flow Diversion Device is improperly assembled.

Apparatus:

Sanitary fitting wrench.

Method:

Observe function of Flow Control Device when Flow Diversion Device is improperly assembled.

Procedure:

  1. With the system in operation with cold water and the Flow Diversion Device in diverted position unscrew by one-half turn, the 13H hex nut which holds the top of the valve to the valve body. This should de-energize the Flow Control Device and all other flow promoters. This test should be run with no piping connected to the forward flow port of the Flow Diversion Device since there can be sufficient force from the piping to keep the forward flow port tightly clamped even though the hex nut is loosened.
  2. With the system in operation with cold water and Flow Diversion Device in diverted position, remove the connecting key located at the base of the valve stem. The Flow Control Device and all other flow promoters should be de-energized.
  3. Record results.

Corrective Action:

If Flow Control Device fails to respond as indicated, immediate checks of the device assembly and wiring are required to locate and correct the cause.

contents

Test 13: Device Assembly, Dual Stem Device

Application:

To all dual stem Flow Diversion Devices used with HTST and HHST pasteurizers.

Frequency:

Upon installation, at least once every 6 months thereafter and when microswitch is re-set or replaced.

Criteria:

The Flow Control Device and all other flow promoters stops or by-passed when the Flow Diversion Device is improperly assembled.

Apparatus:

Tools to dismantle Flow Diversion Device.

Method:

Observe function of Flow Control Device and all other flow promoters when Flow Diversion Device is improperly assembled.

Procedure A:

  1. While the pasteurizer is not operating, with the Flow Diversion Device in diverted flow, remove one actuator clamp.
  2. Move the Flow Diversion Device to the forward flow position using the "Inspect" position of the selector switch and disconnect stem from actuator.
  3. Move the Flow Diversion Device to the diverted flow position using the "Process" position of the selector switch and turn on the Flow Control Device. The Flow Control Device and all other flow promoters should not run or bypassed.
  4. Reassemble the Flow Diversion Device by moving it to the forward flow position and reconnecting the stem to the actuator.
  5. Move the Flow Diversion Device to the diverted flow position and replace the actuator clamp.
  6. Repeat the procedure for the other actuator.
  7. Record results.

Procedure B:

  1. With the Flow Diversion Device in the diverted flow position, move the microswitch away from the contact groove in the valve stem. Observe that the Flow Control Device and all other flow promoting devices are stopped or by-passed.
  2. Record results.

Procedure C:

  1. With the pasteurizer system in forward flow, insert a nut into the diversion valve quick exhaust port.
  2. Reduce the processing temperature below the cut-out temperature.
  3. Observe that the diversion valve does not immediately move to the fully diverted position, that all flow promoters stop and separator is by-passed.
  4. Repeat the test for leak detect valve.
  5. Record the results.

Procedure D: (For systems with a Magnetic Flow Meter System used as a Flow Control Device)

  1. With the pasteurizer system in forward flow, insert a nut into the diversion valve quick exhaust port.
  2. Activate the high flow alarm.
  3. Observe that the diversion valve does not immediately move to the fully diverted position, that all flow promoters stop and separator is by-passed.
  4. Activate the low flow alarm or loss of signal alarm.
  5. Observe that the diversion valve does not immediately move to the fully diverted position, that all flow promoters stop and separator is by-passed.
  6. Repeat the test for leak detect valve.
  7. Record the results

Corrective Action:

If Flow Control Device fails to respond as indicated, an immediate check of the device assembly and wiring is required to locate and correct the cause.

Figure 3 - Value Exploded View
Figure - Value Exploded View. Description follows.
Description of image - Valve Exploded View

This schematic is a dual stem diversion device, exploded view. It shows the different parts of a dual stem flow diversion device, broken apart into the lower body, upper body, microswitch along with the control panel. The components include:

  1. Lower body - divert valve
  2. Valve plug assembly
  3. "O" Ring - Valve plug stem
  4. Clamp - body
  5. Gasket - body
  6. Body Assembly - valve
  7. Clamp - actuator
  8. Connector - hose
  9. Quick exhaust valve
  10. Nipple - pipe
  11. Actuator Assembly (complete)
  12. Upper body valve
  13. Actuator assembly
  14. "O" Ring - Base plate to housing
  15. Cable assembly
  16. Nut - Cable grommet
  17. Grommet - cable
  18. Acorn nut
  19. Washer
  20. Housing - microswitch
  21. Screw - cover bracket
  22. Lockwasher - cover bracket
  23. Screw - Microswitch bracket
  24. Bracket cover
  25. Loop clamp
  26. Screw - Loop clamp
  27. Screw - Microswitch Adjusting
  28. Spring
  29. Bracket - Microswitch
  30. Bracket - Microswitch Adjusting
  31. Block - Microswitch mounting
  32. Microswitch
  33. Washer
  34. Screw - microswitch
  35. Control panel (complete)

Reference: Milk Pasteurization Controls and Tests (Red cow book), 8th Edition, 2003.

List: Dual Stem Flow Diversion Device Tri-Clover Model 262-121
Key Description

  1. Lower Body - Divert Valve
  2. Valve Plug Assembly
  3. "O" Ring - Valve Plug Stem
  4. Clamp - Body
  5. Gasket - Body
  6. Body Assembly - Valve
  7. Clamp - Actuator
  8. Connector - Hose
  9. Quick Exhaust Valve
  10. Nipple - Pipe
  11. Actuator Assembly (Complete)
  12. Upper Body - Valve
  13. Actuator Assembly
  14. "O" Ring - Base Plate To Housing
  15. Cable Assembly
  16. Nut - Cable Grommet
  17. Grommet - Cable
  18. Acorn Nut
  19. Washer
  20. Housing - Microswitch
  21. Screw - Cover Bracket
  22. Lockwasher - Cover Bracket
  23. Screw - Microswitch Bracket
  24. Bracket - Cover
  25. Loop Clamp
  26. Screw - Loop Clamp
  27. Screw - Microswitch Adjusting
  28. Spring
  29. Bracket - Microswitch
  30. Bracket - Microswitch Adjusting
  31. Block - Microswitch Mounting
  32. Microswitch
  33. Washer
  34. Screw - Microswitch
  35. Control Panel (Complete)

Test 14: Manual Diversion

Application:

HTST system with a booster pump.

Frequency:

Upon installation and at least once every 6 months thereafter.

Criteria:

When Flow Diversion Device is manually diverted, booster pump stops, frequency pen records a diverted flow position, green light goes out, red light comes on and pressure differential is maintained.

Apparatus:

None.

Method:

Observe the response of the system to manual diversion.

Procedure:

  1. With HTST system in operation and the Flow Diversion Device in the forward flow position, press the manual diversion button. Observe that the flow diversion valve assumes the divert position, and the booster pump stops. The frequency pen should record a diverted flow position, and the green light goes out while the red light comes on. The pressure differential between raw and pasteurized milk in the regenerator should be maintained.
  2. Activate the manual button while operating the HTST system at its maximum operating pressure. Confirm that the spring tension of the Flow Diversion Device is capable of diverting the system at maximum operating pressure.
  3. Operate the HTST system in forward flow and activate the manual divert button until the raw side pressure reaches zero (0) psi. Release the manual divert button and observe that the pressure differential between raw and pasteurized milk in the regenerator is maintained.
  4. Record the results.

Corrective Action:

If the above described actions do not occur when procedures 1,2 and 3 are performed, or the necessary pressure differential between raw and pasteurized milk is not maintained, the assembly and wiring of the HTST system must be immediately reviewed and the indicated deficiencies corrected or proper adjustments made.

Test 15: Response Time

Application:

To all Flow Diversion Devices used with HTST pasteurizer and HHST systems which use a dual stem valve assembly.

Frequency:

Upon installation and at least once every 6 months thereafter.

Criteria:

The Flow Diversion Device moves from the fully forward to the fully diverted position in no more than one second.

Apparatus:

  1. Stopwatch.
  2. Water, oil or other suitable media bath.

Method:

Determine the elapsed time between the instant of the activation of the control mechanism at cut-out temperature on declining temperature and the instant the Flow Diversion Device takes the fully diverted flow position.

Procedure:

  1. Place the temperature sensing probe of the Safety Thermal Limit Recorder into the water, oil or other suitable media bath.
  2. With water, oil or other suitable media bath at a temperature above cut-out temperature, allow the water, oil or other suitable media to cool gradually. At the moment the cut-out mechanism is activated, start the watch and the moment the Flow Diversion Device takes the fully diverted position, stop the watch. On a dual stem device, both valves should move simultaneously.
  3. Record results. The response time interval must not exceed one second.

Corrective Action:

Should response time exceed 1 second, immediate corrective action must be taken.

Test 16: Valve Flush Time Delay

Application:

To all dual stem flow diversion devices in which product may be pocketed between the two valve seats while the valve is in diverted flow position (applicable to HTST only).

Frequency:

  1. Upon installation and at least once every 6 months thereafter.
  2. Whenever the seal on the time delay relay is broken.

Criteria:

There shall be a flush of the transitional cavity between the two valves of at least one (1) second. If a restrictor is installed in the divert line, the delay shall be no longer than three (3) seconds. The maximum three seconds of delay is not applicable when the timing system is magnetic flow meter based.

Apparatus:

Stopwatch.

Method:

When the flow diversion device moves from the diverted flow position to the forward flow position, the cavity located between the two valve bodies shall receive an adequate flush to remove stale product, but this flush should not compromise the required hold time.

Procedure:

  1. Operate the pasteurizer in diverted flow position.
  2. Raise the temperature to a point above the cut-in temperature.
  3. At the instant the divert (first) valve begins to move into its "forward flow" position, start the stopwatch.
  4. At the instant the leak detect valve begins to move, stop the stopwatch.
  5. Record the result and adjust the time delay relay if necessary (and seal the time delay relay or its enclosure).

Corrective Action:

Should the valve flush time be less than one (1) second and greater than three (3) seconds in restrictor installed divert line, immediate corrective action must be taken.

Test 17: Time Delay Interlock With Flow Control Device

Application:

To dual stem Flow Diversion Devices with a manual forward flow switch (inspect position on the mode switch) (applicable to HTST and HHST pasteurizers).

Frequency:

Upon installation and at least once every 6 months thereafter.

Criteria:

To verify that the system cannot enter a manually induced forward flow position while the Flow Control Device is running or any flow promoting device located between the constant level tank and the vacuum breaker is active.

Apparatus:

None.

Method:

Determine that the Flow Diversion Device does not assume a manually induced forward flow position while Flow Control Device is running or any flow promoting device located between the constant level tank and the vacuum breaker is active.

Procedure:

With the system running in forward flow, move the control switch to the "Inspect" position and observe that the following events automatically occur in sequence:

  1. The Flow Diversion Device immediately moves to the diverted flow position and the Flow Control Device is turned off.
  2. The Flow Diversion Device remains in the diverted flow position while the Flow Control Device is running down.
  3. All flow promoting devices are either de-energized or by-passed.
  4. After the Flow Control Device stops running, the Flow Diversion Device assumes the forward flow position. All flow promoting devices remain de-energized or by-passed.
  5. Record results and seal the timer or enclosure.

Corrective Action:

If the above sequence of events does not occur, either a timer adjustment or wiring change is required.

Test 18: CIP Time Delay Relay

Application:

To all HTST and HHST pasteurizer systems in which it is desired to run the Flow Control Device and/or other flow promoting device during the CIP cycle.

Frequency:

  1. Upon installation and at least once every 6 months thereafter.
  2. Whenever the seal on the time delay relay is broken.

Criteria:

When the mode switch on the Flow Diversion Device is moved from "Process Product" to "CIP", the Flow Diversion Device shall move immediately to the diverted position and remain in the diverted position for at least 10 minutes before starting its normal cycling in the CIP mode. In HTST systems the booster pump shall be turned off and shall not run during the 10 minute time delay.

Apparatus:

Stopwatch.

Method:

Adjust the set point on the time delay relay equal to or greater than 10 minutes.

Procedure:

  1. Operate pasteurizer in forward flow with the mode switch on the Flow Diversion Device in the "Process Product" position, at a flow rate below the value at which holding time was measured, using water above pasteurization temperature.
  2. Move the mode switch on the Flow Diversion Device to the "CIP" position. The Flow Diversion Device shall move immediately to the diverted position and the booster pump shall stop running.
  3. Start the stopwatch when the Flow Diversion Device moves to the diverted position.
  4. Stop the stopwatch when the Flow Diversion Device moves to the forward flow position for its initial cycle in the CIP mode or when the booster pump starts.
  5. Record results. The time delay must be at least 10 minutes.

Corrective Action:

If the Flow Diversion Device does not remain in the diverted position for at least 10 minutes after the mode switch is moved from "Process Product" to "CIP", increase the set point on the time delay relay and repeat this test procedure. If the booster pump runs at any time during the 10 minute delay, the booster pump wiring is in need of repair.

D. Pressure differential

Test 19: Pinholes Check - Dye Recirculation Procedure

Note: Other effective tests (e.g. spraying dye, Freon method, helium test, pressure method, Testex Procedure) are also acceptable. For other effective tests used, the establishment must have validated written procedures.

Application:

All heat transfer plates of HTST, APPS and HHST pasteurizers and all other transfer plate systems in the establishment.

Frequency:

At least once a year and more often if the integrity of the transfer plates is in question.

Criteria:

To check for pinholes in the heat transfer plates.

Apparatus:

Connections and fittings to circulate the back side of all non-product surfaces of plates (i.e. hot water, chill water and glycol sections) and raw side of regenerator in one complete circuit.

Method:

Circulate potassium permanganate solution on both sides of heat exchanger plates. A pinhole in plate will show dye on 2 plates - the one with leak and the one opposite.

Procedure:

  1. Clean up pasteurizer system in a normal manner.
  2. Make necessary connections to circulate the back side of all non-product surfaces of plates (hot water, chill water and glycol sections). This should be accomplished with one circulation to clean all sections at one time.
  3. Fill constant level tank with water. Begin pumping water to flush back side of plates until water runs clear.
  4. Direct flow to constant level tank to start circulation.
  5. Clean both sides of the plates properly with a recommended procedure. Flush thoroughly with warm or hot water.
  6. Open up the heat exchanger. Inspect each plate for proper cleaning. Plates which are not cleaned will need hand scrubbing to get clean.
  7. If plates are clean leave plates spread apart and spaced to allow drying. All plates must be dry and clean before proceeding to the next step.
  8. Close up the heat exchanger. Hook up to circulate non-product side of plates as well as raw side of the regenerator in one complete circuit.
  9. Add water to constant level tank - do not turn on pump.
  10. Mix in potassium permanganate dye in constant level tank using a stirring rod. (Approximately 3.5 kg per 1000 litres water).
  11. Begin pumping potassium permanganate solution and adding water if necessary to keep constant level tank from running dry. Stop adding water when level in constant level tank is satisfied.
  12. Add approximately 4.5 litres liquid caustic solution (or 2.5 kg caustic powder mixed in 5 litres water) to constant level tank.
  13. Heat to 82°C. Turn off the steam supply once this temperature is reached.
  14. Circulate for 30 minutes. Do not be concerned with drop in temperature during remainder circulation period.
  15. Pump dye solution to floor drain until constant level tank runs dry. Do not add water.
  16. Shut off pump when reservoir runs dry.
  17. Disconnect connections. Allow the heat exchanger to drain. Rinse off the floor and outside of the heat exchanger while the heat exchanger is draining.
  18. Open up the heat exchanger and allow to drain completely. Rinse any dye solution traces from exterior of equipment, floor etc.. Inspect each pair of product plates.
  19. A hole in the heat exchanger will show potassium permanganate dye on 2 plates i.e. the one with leak and one opposite.
  20. It will be necessary to manually dye check both plates to determine which is leaking.
  21. After all plates have been inspected reconnect and circulate Oxalic acid at the rate of 100 mL per 45 litres of water through same circuit as the potassium permanganate dye solution to neutralize the dye. Heat to 60°C. Use Oxalic acid solution from the constant level tank to clean dye from all areas where splattering has occurred.
  22. Connect the heat exchanger up for normal product clean-up and re-clean with normal procedure.
  23. Keep records to show proper testing has occurred and corrective action, if required has been taken.

Corrective Action:

Replace all heat transfer plates with pinholes.

Test 20: Pressure Differential Controller

Application:

To those pressure differential controllers having pneumatically driven pointers, used to control the operation of booster pumps on HTST pasteurizers. In the case of product-to-heat transfer medium-to-product type regeneration, the heat transfer medium pump is considered as the booster pump.

Frequency:

Upon installation and at least once every 6 months thereafter.

Criteria:

To verify that the booster pump shall not operate, unless the product pressure in the pasteurized side of regenerator is at least 2 psi (14 Kpa) greater than the product pressure in the raw side of the regenerator.

Apparatus:

Optional - Pneumatic testing device as shown in figure 4.

Method:

The pressure differential controller is checked and adjusted to prevent operation of the booster pump, unless the product pressure in the pasteurized side of the regenerator is at least 2 psi (14 Kpa) greater than pressure in the raw side of the regenerator.

Procedure A:

  1. Loosen the connections at both pressure sensors and wait for any liquid to drain through the loose connections. Observe that both pointers are within ±0.5 psi of zero psi (0 Kpa).
  2. Remove both sensors from the process and mount them in a tee, either at the discharge of the booster pump, or connected to the pneumatic testing device. Note the difference between the sensor readings. The change in elevations of the sensors may have caused some change in the zero readings.
  3. Turn on the booster pump switch and depress the test push button to operate the booster pump. Observe that the difference between the sensor readings is within 1 psi (7 Kpa) of that observed before pressure was applied.
  4. Turn off the booster pump switch and return the pressure sensors to their normal process locations.
  5. Manually move and hold the white pointer (raw side of the regenerator) at the normal operating pressure of the booster pump.
  6. Press the test button while manually moving the orange pointer (pasteurized side of the regenerator) upscale until the pilot light turns on, then slowly move the orange pointer downscale until pilot light turns off.
  7. Observe that the pilot light does not turn on until the orange pointer is at least 2 psi (14 Kpa) higher than white pointer, and the pilot light turns off when the orange pointer is no less than 2 psi (14 Kpa) higher than the white pointer.
  8. If necessary, adjust the differential setting.

Note: The test may also be completed using a pneumatic testing device capable of producing differential pressures on the probes. This device should be capable of performing and be operated in a manner so as to duplicate the conditions described above.

Procedure B:

Application:

As above and to electronically operated pressure differential controllers.

Procedure:
  1. Follow steps 1) and 2) in procedure A.
  2. Operate the system in forward flow.
  3. Reduce the pressure in the pasteurized product regenerator section by slowly opening the back pressure control valve, or increase the raw product pressure by slowly opening the flow control valve (if present) located between the booster pump and the raw product pressure sensor.
  4. Observe that the booster pump stops and the pressure differential controller pilot light goes out when the pasteurized product pressure is no less than 2 psi (14 Kpa) higher than raw product pressure. The booster pump cut out point is indicated by sudden decrease in raw product pressure.

Note: The 2 psi (14 Kpa) differential represents the sum of the 1 psi (7 Kpa) differential required between raw and pasteurized product in the regenerator, plus the 1 psi (7 Kpa) imprecision permitted between the two pressure sensors. Should the pasteurized milk regenerator outlet be at the bottom of the pasteurizer, the pressure differential must be increased by the head pressure within the pasteurizer.

Note: This test may also be completed by using a pneumatic testing device consisting of two independently adjusted pressure connections to simulate raw and pasteurized product pressure conditions.

Figure 4 - Pneumatic Testing Device
Figure - Pneumatic Testing Device. Description follows.
Description of image - Pneumatic Testing Device

This schematic describes the basic design and components of a pneumatic testing device. Components are:

  • Air gauge or sensing element
  • Reducer
  • Tee
  • Pressure switch or sensing element
  • Reducer
  • Cap of correct type, drilled and tapped to accept ¼" pipe
  • 0-100 PSIG gauge ½% accuracy
  • Needle valve
  • Vent
  • Pressure regulator
  • Air supply min. - 70 PSIG (pounds per square inch gauge)

Test 20.1: Interwiring of the Pressure Differential Recorder Controller with the Flow Diversion Device

Application:
  1. To all differential pressure controllers used to control the operation of flow diversion devices on HHST systems when no vacuum breaker is located downstream from the holding tube, and
  2. To all differential pressure controllers used to control the operation of flow diversion devices, product divert systems, product divert valve(s) or other acceptable control systems used in APPS.
Frequency:

Upon installation and at least once every 6 months thereafter.

Criteria:

The differential controller shall be interwired with the flow diversion device so that divert occurs when the sterilized product pressure in the regenerator drops to less than 2 psi (14 Kpa) from that on the raw side of the regenerator and remains in diverted flow until proper pressures are re-established. In the case of product-to-heat transfer medium-to-product regenerators, where the protection is on the pasteurized or aseptic side, the "heat transfer medium" side of the regenerator is considered to be the "raw product" side for purposes of this test.

Apparatus:
  1. Sanitary pressure gauge.
  2. Pneumatic testing device as shown in Figure 4.
Method:

The differential pressure switch is checked and adjusted to prevent forward flow, unless the product pressure in the pasteurized side of the regenerator is at least 2 psi (14 Kpa) greater than the pressure in the raw product side of the regenerator. In the case of product to water to product regenerators protected on the pasteurized or aseptic side, the water side of the regenerator shall be considered to be the "raw product" for purposes of this test.

Procedure:
  1. Wire the test lamp in series with the signal from the pressure differential switch to the flow diversion device.
  2. Calibrate the pressure switch and probes (using Test 20, Procedure A).
  3. Adjust the pressure on the pressure switch sensors to their normal operating pressures (with the pasteurized, or aseptic pressure at least 14 Kpa (2 psi) higher than the raw product pressure.
  4. The test lamp should be lit. If the test light is not lit, increase the pasteurized, or aseptic pressure (or lower the raw product pressure) until the test light is lit.
  5. Gradually lower the pasteurized, or aseptic side (or raise the raw product pressure) until the test light turns off.
  6. The test light should turn off when the pasteurized or aseptic pressure is at least 14 Kpa (2 psi) higher than the raw product pressure.
  7. Note the differential pressure at the point the light turns off.
  8. Gradually raise the pasteurized, or aseptic pressure (or lower the raw product pressure) until the test light turns on.
  9. The test light should not turn on until the pasteurized, or aseptic pressure is greater than 14 Kpa (2 psi) higher than the raw product pressure. Note the differential pressure at the point the light turns off.
    Note: This test may be completed using a pneumatic testing device capable of producing differential pressures on the probes. This device should be capable of being operated in a manner so as to duplicate the conditions described above.
  10. Seal the instrument and record the test results for the office record.

Test 21: Pressure Gauges - Displays

Application:

Pressure display of the pressure differential controller and to all pressure gauges on the HTST pasteurizer and any other heat transfer plate systems to monitor pressure.

Frequency:

Upon installation and at least once every 6 months thereafter, and whenever the gauges are adjusted or repaired.

Criteria:

Required pressure gauges and displays shall be accurate.

Apparatus:

  1. Pneumatic testing device as shown in figure 4 or equivalent.
  2. Pressure gauge of known accuracy.

Method:

Verify the accuracy of required pressure gauges and displays with an accurate gauge.

Procedure:

  1. Pressure gauge of known accuracy is connected to one outlet of test apparatus.
  2. Pressure gauge or display sensor being checked is connected to the second outlet of the sanitary tee.
  3. Air is bled into system through third outlet and comparative readings are made throughout the normal operating range for that gauge or display.
  4. Record results.

Corrective Action:

Inaccurate gauges or displays should be returned to the factory for repair. It is not recommended that the plant operator attempt the adjustment of pressure gauges.

Test 22: Booster Pumps - Interwired with Flow Diversion Device

Application:

To all booster pumps used for HTST pasteurizer systems. In product-to-heat transfer medium-to-product type regeneration, the heat transfer medium pump is considered as the booster pump.

Frequency:

Upon installation and at least once every 6 months thereafter, and after any change in the booster pump or switch circuits.

Criteria:

The booster pump shall be wired so it cannot operate if the Flow Diversion Device is in the diverted position.

Apparatus:

  1. Pneumatic testing device as shown in figure 4.
  2. Sanitary pressure gauge.
  3. Suitable means of heating the water bath.

Method:

Determine if the booster pump stops by dropping the temperature and causing the Flow Diversion Device to divert.

Procedure:

  1. Connect pasteurization pressure sensor to the tee of the testing device with the other end of the tee capped.
  2. Turn on the air supply to provide an adequate pressure differential.
  3. Place the Safety Thermal Limit Recorder probe in the hot water bath, which is above the cut-in temperature.
  4. Cap the Safety Thermal Limit Recorder probe and pasteurized sensor port if the pasteurizer has water in it.
  5. Turn on the Flow Control Device. At this time, the booster pump should start to run.
  6. Remove the Safety Thermal Limit Recorder probe from the hot water bath.
  7. When the Flow Diversion Device moves to the diverted flow position, the booster pump must stop.
  8. Ensure that the pressure differential remains adequate and the Flow Control Device continues to operate following its momentary pause during the Flow Diversion Device transition.
  9. Record the test results.

Corrective Action:

If the booster pump fails to stop when the flow-diversion device is in the diverted flow position, have the plant maintenance personnel check the wiring and correct the cause.

Test 23: Booster Pumps - Interwired with Pressure Differential Controller

Application:

To all booster pumps used for HTST pasteurizer systems. In product-to-heat transfer medium-to-product type regeneration, the heat transfer medium pump is considered as the booster pump.

Frequency:

Upon installation and at least once every 6 months thereafter, and after any change in the booster pump or switch circuits.

Criteria:

The booster pump shall be wired so it cannot operate if the pasteurized product pressure in the regenerator does not exceed, by at least 2 psi (14 Kpa), the product pressure in the raw side of the regenerator.

Apparatus:

  1. Pneumatic testing device as shown in figure 4.
  2. Sanitary pressure gauge.
  3. Suitable means of heating the water bath.

Method:

Determine if the booster pump stops when the pressure differential is not properly maintained in the regenerator.

Procedure:

  1. Connect pasteurization pressure sensor to the tee of the testing device with the other end of the tee capped.
  2. Turn on the air supply to provide an adequate pressure differential.
  3. Place the Safety Thermal Limit Recorder probe in the hot water bath, which is above the cut-in temperature.
  4. Cap the Safety Thermal Limit Recorder probe and pasteurized sensor port.
  5. Turn on the Flow Control Device. At this time, the booster pump should start to run.
  6. Decrease the air supply to the testing tee until the pressure is less than 2 psi (14 Kpa) of the pressure on the raw milk pressure sensor. The booster pump must stop.
  7. Ensure that the Flow Diversion Device remains in the forward flow position and the Flow Control Device continues to operate.
  8. Record the test results.

Corrective Action:

If the booster pump fails to stop when the pressure differential is not maintained, have the plant maintenance personnel determine and correct the cause.

Test 24: Booster Pumps - Interwired with Flow Control Device (Timing Pump, Metering Pump)

Application:

To all booster pumps used for HTST (In product-to-heat transfer medium-to-product type regeneration, the heat transfer medium pump is considered as the booster pump). To all feed and heat transfer medium pumps used in HHST and aseptic processing systems.

Frequency:

Upon installation and at least once every 6 months thereafter and after any change in the pumps or switch circuits.

Criteria:

The booster/heat transfer medium/feed pump shall be wired so they cannot operate if the Flow Control Device is not in operation.

Apparatus:

  1. Pneumatic testing device as shown in Figure 4.
  2. Sanitary pressure gauge.
  3. Suitable means of heating the water bath.

Method:

Determine if the booster/heat transfer medium/feed pump stops when the Flow Control Device is off.

Procedure:

  1. Connect pasteurization pressure sensor to the tee of the testing device with the other end of the tee capped.
  2. Turn on the air supply to provide an adequate pressure differential.
  3. Place the Safety Thermal Limit Recorder probe in the hot water bath, which is above the cut-in temperature.
  4. Cap the Safety Thermal Limit Recorder probe and pasteurized sensor port.
  5. Turn on the Flow Control Device. At this time, the booster/heat transfer medium/feed pump should start to run.
  6. Turn off the Flow Control Device. The booster/heat transfer medium /feed pump must stop.
  7. Ensure that the pressure differential remains adequate and the Flow Diversion Device remains in forward flow position. Record the test results.

Corrective Action:

If the booster/heat transfer medium/feed pump fails to stop when the Flow Control Device has been turned off, have the plant maintenance personnel determine and correct the cause.

E. Meter Based Timing Systems

Test 25: High Flow Alarm

Application:

To all HTST pasteurizers, HHST and aseptic processing systems using a Meter Based Timing System to replace a positive displacement Flow Control Device.

Frequency:

  1. Upon installation and at least once every 6 months thereafter.
  2. Whenever seal on the flow alarm is broken.

Criteria:

When flow rate equals or exceeds the value at which the holding time was measured, the Flow Diversion Device shall assume the diverted position, even though temperature of the milk in the holding tube is above pasteurization temperature.

Apparatus:

None.

Method:

Adjust the set point of the flow alarm so that the flow is diverted when the flow rate equals or exceeds the value at which holding time was measured.

Procedure:

  1. Operate the HTST, HHST pasteurizer or the aseptic processing equipment in forward flow, below the high flow alarm, using water above pasteurization temperature.
  2. Adjust set point on the alarm slowly downward until the frequency pen on the Flow Recorder indicates that an alarm condition has occurred.
  3. Observe that the Flow Diversion Device moved to the diverted position while water passing through the system remained above pasteurization temperature. Verify that the frequency pen on the Flow Recorder records the duration of the high flow condition.
  4. Record the set point of the flow alarm, the occurrence of flow diversion, and the temperature of water in the holding tube.

Corrective Action:

If the Flow Diversion Device does not move to the diverted position, when the frequency pen of the recorder indicates a diversion, a modification or repair of the control wiring is required.

Test 26: Loss of Signal Alarm

Application:

To all HTST pasteurizers, HHST and aseptic processing systems using a Magnetic Flow Meter System to replace a positive displacement Flow Control Device.

Frequency:

  1. Upon installation and at least once every 6 months thereafter.
  2. Whenever seal on the Flow Alarm is broken.
  3. Whenever alteration is made affecting the holding time, the velocity of the flow or the capacity of the holding tube.
  4. Whenever a check of the system indicates a speed-up.

Criteria:

Forward flow occurs only when flow rates are below the Flow Alarm set point and above (5% of the maximum) the Loss of Signal Alarm set point.

Apparatus:

None.

Method:

By observing the actions of the frequency pen on the Flow Recorder and the position of the Flow Diversion Device.

Procedure:

  1. Operate the HTST, HHST pasteurizer or aseptic processing system with the Flow Diversion Device in the forward flow position, at a flow rate below the Flow Alarm set point and above (5% of the maximum) the Loss of Signal Alarm set point, using water.
  2. Disrupt power to the magnetic flow meter or decrease the flow through the flow meter below the Low Flow Alarm set point.
  3. Observe that the frequency pen of the Flow Recorder records an alarm condition for the duration of the loss of signal or low flow condition, and that the Flow Diversion Device moves to the diverted flow position for the duration of this condition.
  4. Record the results.

Corrective Action:

If the valve does not divert or the pens do not move, adjustment of low flow alarm or modification or repair of control wiring is required.

Test 27: Flow Cut-in and Cut-out

Application:

To all HTST pasteurizers, HHST and aseptic processing systems using a Magnetic Flow Meter System to replace a positive displacement Flow Control Device.

Frequency:

  1. Upon installation and at least once every 6 months thereafter.
  2. Whenever seal on the flow alarm is broken.
  3. Whenever any alteration is made affecting the holding time, the velocity of the flow or the capacity of the holding tube.
  4. Whenever a check of the capacity indicates a speed-up.

Criteria:

Forward flow occurs only when flow rates are below the Flow Alarm set point and above the Loss of Signal Alarm set point.

Apparatus:

None.

Method:

By observing the Recorder readings along the action of the frequency pen on the Flow Recorder.

Procedure:

  1. Operate pasteurizer in forward flow, at a flow rate below the Flow Alarm set point and above Loss of Signal Alarm set point, using water above pasteurization temperature.
  2. Using the Flow Controller, increase flow rate slowly until the frequency pen on the Flow Recorder indicates an alarm condition (flow cut-out point). The Flow Diversion Device will also assume the diverted position.
  3. Observe the reading of flow rate from the Recorder, the instant flow cut-out occurs, as indicated by the frequency pen of the Flow Recorder.
  4. With the pasteurizer operating on water above the pasteurization temperature, with the Flow Diversion Device diverted because of excessive flow rate, slowly decrease flow rate until the frequency pen on the Flow Recorder indicates the start of a forward flow movement (flow cut-in point). Because of the time delay relay described in Test 28, the Flow Diversion Device will not move immediately to the forward flow position.
  5. Observe the reading from the Recorder, the instant flow cut-in occurs, as indicated by the frequency pen of the Flow Recorder.
  6. Record results.

Corrective Action:

If the cut-in or cut-out point occurs at a flow rate equal to or greater than the value at which holding time was measured, adjust the Flow Alarm to a lower set point and repeat the test.

Test 28: Time Delay Relay (Flow Recorder)

Application:

To all HTST pasteurizers using Magnetic Flow Meter System to replace a positive displacement Flow Control Device.

Frequency:

  1. Upon installation and at least once every 6 months thereafter.
  2. Whenever seal on the flow alarm is broken.
  3. Whenever any alteration is made affecting the holding time, the velocity of the flow or the capacity of the holding tube.
  4. Whenever a check of the capacity indicates a speed-up.

Criteria:

Following a flow cut-out, as described in the test for flow cut-in and cut-out (Test 27), forward flow shall not occur until all the product in the holding tube has been held at or above pasteurization temperature for at least the minimum holding time of the product with the longest required holding time (e.g. 15 seconds or 25 seconds for depending on the products).

Apparatus:

Stopwatch.

Method:

Set time delay equal to or greater than the minimum holding time.

Procedure:

  1. Operate pasteurizer in forward flow, at a flow rate below the Flow Alarm set point and above the Loss of Signal Alarm set point, using water above pasteurization temperature.
  2. Using the Flow Controller, increase flow rate slowly until the frequency pen on the Flow Recorder indicates an alarm condition, and the Flow Diversion Device moves to the diverted position. There shall be no time delay between the movements of the frequency pen and the Flow Diversion Device.
  3. With the pasteurizer operating on water above the pasteurization temperature, with the Flow Diversion Device diverted because of excessive flow rate, slowly decrease flow rate.
  4. Start the stopwatch the instant the frequency pen on the Flow Recorder indicates the end of the alarm condition.
  5. Stop the stopwatch the instant the Flow Diversion Device starts to move to the forward flow position. Record results.

Corrective Action:

If the time delay is less than the minimum holding time, increase the time setting on the time delay and repeat this test procedure.

Test 29: Thermal Limit Controller For Control-Sequence Logic

Thermal limit controllers used with HHST and aseptic processing systems that have the flow-diver­sion device located downstream from the regenerator and/or cooler shall be tested by one of the following applicable tests at the frequency specified.

Test 29.1: HHST Pasteurization and Aseptic Processing- Indirect Heating

Application:

To all HHST and aseptic processing systems pas­teurizers using indirect heating. When testing aseptic processing systems, the "product divert system" or "product divert valve" or "acceptable control system" may be substituted for the "flow-diversion device" when it is referenced in this test.

Frequency:
  1. Upon installation, and every 6 months thereafter.
  2. Whenever a seal has been broken.
Criteria:

The pasteurizer or aseptic processing equipment shall not operate in forward flow until the product surfaces downstream from the holding tube have been held at or above the required pasteurization temperature for the required time or, in the case of aseptic processing equipment, sterilized. On start-up, surfaces shall be exposed to fluid at pas­teurization or in the case of aseptic processing equipment, sterilization temperature for at least pas­teurization or sterilization time. If the product tempera­ture falls below the pasteurization or sterilization standard in the holding tube, forward flow shall not be re-achieved until the product surfaces downstream from the holding tube have been re-held at or above the required pasteurization temperature for the required time, or is the case of aseptic processing equipment, re-sterilized.

Apparatus:
  1. Constant tempera­ture water, oil or other suitable media bath.
  2. Test lamp from the pneumatic testing device as shown in figure 4.
Method:

The control-sequence logic of the thermal limit controller is determined by monitoring the electric signal from the thermal limit controller during a series of immersions and remov­als of the two sensing elements from a bath heated above the cut-in temperature.

Procedure:
  1. Heat a constant temperature water, oil or other suitable media bath a few degrees above the cut-in temperature on the thermal limit controller.
  2. Wire the test lamp in series with the signal from the thermal limit controller to the flow-diversion device. If some processors have time delays built into their control logic in excess of that required for public health reasons, bypass these timers or account for their effect in delaying forward flow.
  3. Immerse the holding tube sensing element in the bath, which is above the cut-in temperature. The test lamp should remain unlit, i.e. diverted flow. Leave the sensing element in the bath.
  4. Immerse the 2nd or more as required sensing element in the bath. The test lamp should light up, i.e. forward flow after a minimum time delay of 1 second for continuous flow pasteurization systems. For aseptic processing systems, no delay is required if the filed process includes a documented sterilization period.
  5. Remove the 2nd or more as required elements from the bath. The test lamp should remain lit, i.e. forward flow.
  6. Remove the holding tube sensing element from the bath. The test lamp should go out immediately, i.e. diverted flow, sterilization timer not timing.
  7. Re-immerse the sensing element of the holding tube in the bath. The test lamp should remain unlit, i.e. diverted flow. Record results.
  8. With all elements in the bath observe the sterilization timer. Start the watch when the test lamps light (cut-in temperature) turns on.
  9. Record the time. Compare the results to the Scheduled Process to verify that the time meets that specified by the Process Authority.
  10. Stop the watch when the sterilization timer has elapsed.
  11. Record this time.
Corrective Action:

If the control-sequence logic of the thermal limit con­troller does not follow the pattern set out in the procedures section, the instrument shall be rewired to conform to this logic.

Test 29.2: HHST Pasteurization and Aseptic Processing - Direct Heating

Application:

To all HHST pasteurizers and aseptic processing systems using direct contact heating. When testing aseptic processing systems, the "product divert system" or "product divert valve" or "acceptable control system" may be substituted for the "flow-diversion device" when it is referenced in this test.

Frequency:
  1. Upon installation, and every 6 months thereafter.
  2. Whenever a seal has been broken.
Criteria:

The pasteurizer or aseptic processing equipment shall not operate in forward flow until the product surfaces downstream from the holding tube have been held at or above the required pasteurization temperature for the required time or, in the case of aseptic processing equipment, sterilized. On start-up, surfaces shall be exposed to fluid at pas­teurization or in the case of aseptic processing equipment, sterilization temperature for at least pas­teurization or sterilization time. If the product tempera­ture falls below the pasteurization or sterilization standard in the holding tube, forward flow shall not be re-achieved until the product surfaces downstream from the holding tube have been re-held at or above the required pasteurization temperature for the required time, or is the case of aseptic processing equipment, re-sterilized.

Apparatus:
  1. Constant tempera­ture water, oil or other suitable media bath.
  2. Test lamp from the pneumatic testing device as shown in figure 4.
Method:

The control-sequence logic of the thermal limit controller is determined by monitoring the electric signal from the thermal limit controller during a series of immersions and remov­als of the three sensing elements from a bath heated above the cut-in temperature.

Procedure:
  1. Heat a water, oil or other suitable media bath to a constant temperature, a few degrees above the cut-in temperature on the ther­mal limit controller.
  2. Wire the test lamp in series with the signal from the thermal limit controller to the flow-diversion device. If some processors have time delays built into their control logic in excess of that required for public health reasons, bypass these timers or account for their effect in delaying forward flow. The pressure switches which must be closed to achieve forward flow must also be bypassed before performing this test.
  3. Immerse the sensing ele­ment from the flow-diversion device in the bath which is above the cut-in tempera­ture. The test lamp should remain un­lit, i.e. diverted flow. Remove this sensing element from the bath.
  4. Immerse the sensing ele­ment from the vacuum chamber in the bath. The test lamp should remain un­lit, i.e. diverted flow. Remove the sensing element from the bath.
  5. Immerse two sensing ele­ments, from the vacuum chamber and flow-diver­sion device in the bath. The test lamp should remain unlit, i.e. diverted flow. Leave the two sensing elements in the bath.
  6. Immerse the sensing ele­ment from the holding tube in the bath. The test lamp should light up, i.e. forward flow after a minimum time delay of 1 second for continuous flow pasteurization systems. For aseptic processing systems, no delay is required if the filed process includes a documented sterilization period.
  7. Remove one sensing ele­ment, the flow-diversion device, from the bath. The test lamp should remain lit, i.e. forward flow.
  8. Remove another sensing ele­ment, the vacuum chamber from the bath. The test lamp should remain lit, i.e. forward flow.
  9. Remove the last sensing ele­ment, the holding tube from the bath. The test lamp should go out immediately, i.e. diverted flow.
  10. Re-immerse the sensing ele­ment, holding tube in the bath. The test lamp should remain unlit, i.e. di­verted flow.
  11. Record results.
  12. Re-seal regulatory controls as necessary.
Corrective Action:

If the control-sequence logic of the thermal limit con­troller does not follow the pattern set out in the procedures section, the instrument shall be rewired to conform to this logic.

Test 30: Setting of Control Switches for Product Pressure in the Holding Tube

Application:

To all HHST pasteurizers and aseptic processing systems which are capable of operating with product in forward flow mode, with less than 518 Kpa (75 psig) pressure in the holding tube. When testing aseptic processing systems, the "product divert system" or "product divert valve" or "acceptable control system" may be substituted for the "flow-diversion device" when it is referenced in this test.

Frequency:

  1. Upon installation and at least once every 6 months thereafter.
  2. Whenever the pressure switch seal is broken.
  3. When­ever the operating temperature is changed.

Criteria:

The pasteurizer or aseptic processor shall not operate in forward flow unless the product pressure in the holding tube is at least 69 Kpa (10 psi) above the boiling pressure of the product.

Apparatus:

  1. Sanitary pressure gauge.
  2. Test lamp from the pneumatic testing device as shown in figure 4.

Method:

The pressure switch is checked and adjusted so as to prevent forward flow unless the product pressure in the holding tube is at least 69 Kpa (10 psi) above the boiling pressure of the product.

Procedure:

  1. From Figure 1-5, deter­mine the pressure switch setting necessary for the operating temperature (not the diversion temperature) being used in the process.
  2. Install the sanitary pressure gauge of known accuracy and the pressure switch sensing element on the pneumatic testing device.
  3. Remove the seal and cover to expose the adjustment mechan­ism on the pressure switch.
  4. Place the test lamp in series with the pressure switch contacts or use some other method to monitor the cut-in signal.
  5. Apply air pres­sure to the sensing element, and deter­mine the pressure gauge reading at the cut-in point of the switch which will light the test lamp. If the switch is short cir­cuited, the lamp will be lit before air pressure is applied.
  6. Determine that the cut-in pressure on the switch is equivalent to or greater than the required pressure from the figure below.
  7. Record results.
  8. Where adjustment is necessary, refer to manufacturer's instruc­tion.
  9. After adjustment, repeat the above proced­ure.
  10. When the results are satisfactory, seal the pressure switch setting.
  11. For each operating temper­ature on HHST pasteurizers using direct contact heating, the product pressure switch setting is determined from the figure below.

Note: The pressure setting shall be adjusted upward by the difference between local normal atmospheric pressure and at sea level.

Table 40 – Pressure Switch Settings
Figure - Pressure Switch Settings. Description follows.
Description of image - Pressure Switch Settings

This chart shows the operating temperatures of different pressure switch settings at sea level.

At temperatures of 191°Fahrenheit (F) to 210°Fahrenheit the pressure switch setting is 10 pounds per square inch gauge (PSIG) at sea level.

  • At 220°F the pressure switch setting is 13 PSIG at sea level.
  • At 230°F the pressure switch setting is 16 PSIG at sea level.
  • At 240°F the pressure switch setting is 20 PSIG at sea level.
  • At 250°F the pressure switch setting is 25 PSIG at sea level.
  • At 260°F the pressure switch setting is 31 PSIG at sea level.
  • At 270°F the pressure switch setting is 37 PSIG at sea level.
  • At 280°F the pressure switch setting is 45 PSIG at sea level.
  • At 290°F the pressure switch setting is 53 PSIG at sea level.
  • At 300°F the pressure switch setting is 62 PSIG at sea level.

Test 31: Setting of Control Switches for Differential Pressure across the Injector

Application:

To all HHST pas­teurizers and aseptic processing systems using direct contact heating. When testing aseptic processing systems, the "product divert system" or "product divert valve" or "acceptable control system" may be substituted for the "flow-diversion device" when it is referenced in this test.

Frequency:

  1. Upon installation and at least once every 6 months thereafter.
  2. Whenever the differential pressure controller seal is broken.

Criteria:

The pasteurizer or aseptic processor shall not operate in forward flow unless the product pressure drop across the injector is at least 69 Kpa (10 psi).

Apparatus:

  1. Sanitary pressure gauge.
  2. Test lamp from the pneumatic testing device as shown in figure 4.

Method:

Check the differential pressure switch and adjust it so as to prevent forward flow unless the differen­tial pressure across the injector is at least 69 Kpa (10 psi).

Procedure:

A. Calibration of the Injector Differential Pressure Controller Probes:
  1. Loosen the connection at both pressure sensors and allow for any liquid to drain through the loose connections. Both pointers, or digital displays, shall be within 3.5 Kpa (0.5 psi) of 0 Kpa (0 psi). If not, adjust the pointer(s), or digital display(s), to read 0 Kpa (0 psi).
  2. Remove both sensors and mount them in a tee, or connect them to a pneumatic testing device. Record any difference in the zero (0 Kpa (0 psi)) readings that may have occurred because of this change in elevation.
  3. Attach the tee and both sensors to a pneumatic testing device and adjust the air pressure to the normal operating pressure used at the injector. The pointer or digital display reading separation is to be within 6.9 Kpa (1 psi) of that observed before the pressure was applied. If this is not the case, the instrument requires adjustment or repair.
  4. When the results are satisfactory, record the test results and proceed as directed below.
B. Setting of the Injector Differential Pressure Controller Switch:
  1. Disconnect the sanitary pressure sensing element that is normally located after the steam injector from the pneumatic testing device and cap the resulting opening. Leave the pressure sensing element, which is installed prior to the steam injection, on the pneumatic testing device.
  2. Leave the other pressure sensing element open to the atmosphere, but at the same height as the sensing element connected to the pneumatic testing device.
  3. Wire the test lamp in series with the differential controller micro-switch or use the method provided by the instrument manufacturer to monitor the cut-in signal.
  4. Apply air pressure to the sensing element and determine, from the test lamp, the pressure gauge reading at the cut-in point of the differential pressure switch.
  5. The differential pressure cut-in on the controller shall be at least 69 Kpa (10 psi). Adjust if necessary. Refer to the manufacturer's instructions.
  6. After adjustment, repeat the test.
  7. Once results are satisfactory, seal the instrument and record the results.

Note: this test is to assure at least a 10 psi pressure loss of product at exit end of the steam injector. This assures complete condensation of the steam within the injector.

F. Other

Test 32: Leak-Protector Valve on Batch Pasteurizer Outlet Valves

Application:

All batch pasteurizer outlet valves.

Frequency:

Upon installation and at least once every 6 months thereafter.

Criteria:

No leakage of milk or milk product past the outlet valve seat in any closed position.

Apparatus:

None.

Method:

  1. Fill the batch (vat) to the level of normal operation with milk, milk product or water so that pressure is exerted against the closed outlet valve.
  2. Observe if there is any leaking milk, milk product or water past the outlet valve seat into the valve outlet when pressure is exerted against the upstream face of the valve.
  3. Turn the outlet valve to the just-closed position and examine for any leakage into the valve outlet.
  4. Record the findings.

Corrective Action:

If leakage past the outlet valve seat should occur in any closed position, the outlet valve plug should be re-ground, gaskets replaced, or any other necessary steps shall be taken to prevent leakage.

G. Appendices

Appendix 18 - 1: Testing Apparatus Specifications

1. Test Thermometer

Type:
Mercury-actuated; readily cleanable; plain front enamelled back; length 305 millimetres (12 inches); immersion point to be etched on stem; mercury to stand in contraction chamber at 0°C (32°F).
Scale Range:
At least 7°C (12°F) below and 7°C (12°F) above the pasteurization temperature at which the operating thermometer is used, with extensions of scale on either side permitted; protected against damage at 149°C (300°F).
Temperature Represented by Smallest Scale Division:
0.1°C (0.2°F).
Number of degrees per 25 mL (Inch) of Scale:
Not more than 4 degrees Celsius or not more than 6 degrees Fahrenheit.
Accuracy:
Within 0.1°C (0.2°F), plus or minus, throughout specified scale range. The accuracy shall be checked against a thermometer which has been tested by the National Bureau of Standards.
Bulb:
Corning normal or equally suitable thermometric glass.
Case:
Suitable to provide protection during transit and periods when not in use.

2. Digital Test Thermometer

Type:
Hand-held; high accuracy digital thermometer; and battery or AC line powered. Calibration is protected from unauthorized changes.
Range:
−18°C to 149°C (0°F to 300°F); Temperature represented by smallest scale division, 0.01°C or °F and digital display.
Accuracy:
System accuracy shall meet that specified by the manufacturer of the thermometer. The thermometer shall be fit for purpose and its accuracy shall be checked against a thermometer, which has been tested by the National Bureau of Standards. A certificate of calibration shall be maintained with the unit.
Self-Diagnostic Circuitry:
Circuitry shall provide constant monitoring of all sensing, input and conditioning circuits. The diagnostic circuitry should be capable of identifying the probe and its calibration information. Without a correct connection of the probe, the display shall alert the operator and no temperature will be displayed.
Electromagnetic Compatibility:
Shall be documented for these devices for their intended use and available to the Regulatory Agency. Units to be used in the "field" shall have been tested for heavy industrial standards, as specified in the European Electromagnetic Compatibility Directive.
Immersion:
Minimum immersion point shall be marked on the probe. During control tests, the probes shall be immersed to equal depths in a water or oil bath or other suitable media.
Case:
Suitable to provide protection during transit and periods when not in use.

3. General Purpose Thermometer

Type:
Pocket type; mercury-actuated.
Magnification of Mercury Column:
To apparent width of not less than 1.6 millimetres (0.0625 of an inch).
Scale Range:
C (30°F) to 100°C (212°F), with extension on either side permitted. Protected against damage at 105°C (220°F).
Temperature Represented by Smallest Scale Division:
C (2°F).
Number of Degrees per Inch of Scale:
Not more than 29 degrees Celsius or not more than 52 degrees Fahrenheit.
Accuracy:
Within 1°C (2°F), plus or minus, throughout the specified scale range. Checked periodically against a known accurate thermometer.
Case:
Metal, provided with a fountain pen clip.
Bulb:
Corning normal or equally suitable thermometric glass.

4. Electrical Conductivity Measuring Devices

Type:
Wheatstone bridge, Galvanometer, Milliammeter, manual or automatic.
Conductivity:
Capable of detecting change produced by the addition of 10 ppm of sodium chloride, in water of 100 ppm of hardness.
Electrodes:
Standard.
Automatic Instruments:
Electric clock, time divisions not less than 0.2 of a second.

5. Stopwatch

Type:
Open face, indicating fractional seconds.
Accuracy:
Accurate to 0.2 of a second.
Hands:
Sweep hand (if applicable), one complete turn every 60 seconds or less.
Scale:
Divisions of not over 0.2 of a second.
Crown:
Depression of crown or push button starts, stops and resets to zero.

Appendix 18 - 2: Test Procedures Form

Critical Process Equipment and Controls Tests and Calibrations

Name and Address of the Dairy

Registration # space

Provincial # space

HTST unit # space Date

Dairy Specialist/Technician Name and Address

Example of completed form for Booster Pump Test
Task Requirements Test # Results Date Signature
  • 1.11.04.03
  • 1.14.04.03
    (H&S 2)
    Interwiring
  • Only operates when FCD is energized.
  • Only operates with proper pressure differential.
  • Only operates when FDD is in forward flow.
  • 24
  • 23
  • 14 & 22
Example of completed form for Feed Pump
Task Requirements Test # Results Date Signature
  • 1.14.04.03
  • 1.17.04.03
    (H&S 2)
    Interwiring
  • Only operates when FCD is energized.
  • Only operates with proper pressure differential.
24
Example of completed form for Regeneration
Task Requirements Test # Results Date Signature
  • 1.11.05.01
  • 1.14.05.01
  • 1.17.05.01
    (H&S 2)
    General Conditions
No pinholes in heat transfer plates. 19
  • 1.11.05.03
  • 1.14.05.02
  • 1.17.05.02
    (H&S 2)
    Pressure Differentials
Pressure on raw side must always be lower by 14 Kpa (2 psi) than pasteurized side

Raw side regen. inlet (1) space

Past. side regen. outlet (1) space

Raw side regen. inlet (2) space

Past. side regen. outlet (2) space

Example of completed form for Heating /Cooling Sections
Task Requirements Test # Results Date Signature
  • 1.11.07.01
  • 1.11.07.03
  • 1.14.07.01
  • 1.14.14.01
  • 1.17.07.01
  • 1.17.14.01
    (H&S 2)
    General Conditions
No pinholes in heat transfer plates. 19
  • 1.11.07.02
  • 1.14.14.02
  • 1.17.14.02
    (H&S 3, 2)
    Pressure Differentials
Pressure on medium side must always be lower by 14 Kpa (2 psi) than product side

Medium side inlet (1) space

Product side outlet (1) space

Medium side inlet (2) space

Product side outlet (2) space

Make space

Model space

Serial

Example of completed form for Flow Control Device (FCD)
Task Requirements Test # Results Date Signature
1.11.06.02
(H&S 1)
Set and Sealed
Variable speed device; maximum legal flow rate sealed. Salt test at maximum flow rate. 8 and 9 (Procedure under review)
  • 1.14.06.02
  • 1.17.06.02
    (H&S 1) Set and Sealed
Set at a flow rate to achieve the holding time specified in the scheduled process
  • 1.11.06.03
  • 1.14.06.03
  • 1.17.06.03
    (H&S 2)
    Fail Safe (Operation) Capability
Only operate when FDD is in safe forward flow or fully diverted position. (HTST and HHST only) 12 or 13
  • 1.11.06.03
  • 1.14.06.03
  • 1.17.06.03
    (H&S 2)
    Fail Safe (Operation) Capability
Time delay relay if present - not more than 1 sec. (HTST only) Time delay relay space sec.
  • 1.11.06.03
  • 1.14.06.03
  • 1.17.06.03
    (HS 2)
    Fail Safe (Operation) Capability
Meter Based Timing System: High flow alarm - divert flow occurs when flow rate > than the value at which holding time was measured. 25 High flow alarm set point space
  • 1.11.06.03
  • 1.14.06.03
  • 1.17.06.03
    (H&S 2)
    Fail Safe (Operation) Capability
Meter Based Timing System: Low flow/signal loss alarm - divert flow occurs upon low flow alarm or signal loss. 26 Low flow alarm set point space
  • 1.11.06.03
  • 1.14.06.03
  • 1.17.06.03
    (H&S 2)
    Fail Safe (Operation) Capability
Meter Based Timing System: Flow cut-in and cut-out - forward flow occurs only when flow rates < flow alarm set point and > loss of signal alarm set point. 27

Flow cut-in space

Flow cut-out space

  • 1.11.06.03
  • 1.14.06.03
  • 1.17.06.03
    (H&S 2)
    Fail Safe (Operation) Capability
Alarm pen tracks flow pen
Example of completed form for Holding
Task Requirements Test # Results Date Signature
1.11.08.04
(H&S 2)
Holding Verification and Records
Evidence of holding time in both forward and divert flow. Test results converted to all products processed. 8 and 9
(Procedure under review)

Holding time-FWD space

Holding time-DIV space

Flow measurement-water space

Flow measurement-product:

  1. space
  2. space
  3. space
  4. space
  5. space
  6. space

Calculated hold time:

  1. space
  2. space
  3. space
  4. space
  5. space
  6. space
  • 1.14.08.03
  • 1.17.08.03
    (H&S 2)
    Holding Verification and Records
  • Calculation and verification of holding tube length (indirect and direct heating systems)
    • Holding time is determined by calculation method and is specified in the scheduled process.
    • For direct injections systems extra condensate volume from steam added is included in holding tube calculation.
9.1 Procedure under review
Example of completed form for Flow Diversion Device (FDD)
Task Requirements Test # Results Date Signature
  • 1.11.09.01
  • 1.17.09.01
    (H&S 2)
    General Conditions
Valve seats (no leakage) and spring (capable of diverting system at maximum operating pressure) in good condition. (HTST and HHST systems using a dual stem valve assembly)) 10
  • 1.11.09.01
  • 1.17.09.01
    (H&S 2)
    General Conditions
During manual diversion, booster pump stops, frequency pen records diverted flow position, red indicator light comes on and pressure differential is maintained (HTST only) 14
  • 1.11.09.01
  • 1.17.09.01
    (H&S 2)
    General Conditions
Valve stem moves with ease. (HTST) 11
  • 1.11.09.05
  • 1.17.09.04
    (H&S 1)
    Fail Safe Divert
    Capability
Valve response time from forward flow to divert not exceed 1 sec. (HTST and HHST) 15 Valve response time space
  • 1.11.09.05
  • 1.17.09.04
    (H&S 1)
    Fail Safe Divert Capability
Diverts at sub-legal temperature. (HTST only) 6
  • 1.11.09.05
  • 1.17.09.04
    (H&S 1)
    Fail Safe Divert Capability
Diverts with loss of air or power to solenoids.
  • 1.11.09.05
  • 1.17.09.04
    (H&S 1)
    Fail Safe Divert Capability
Interwired with FCD and flow promoters - FCD, stuffing pumps, and accessory homogenizer without open recirculation line, only operating in safe forward flow or fully divert; Booster pump and separator by-pass valves only operating in safe forward flow position. (HTST and HHST) 13
1.11.09.06
(H&S 2)
Time Delay Relays
Flush time between two valve stems - 1 second minimum 16 Valve flush time space
1.11.09.06
(H&S 2)
Time Delay Relays
Inspect delay - FDD diverts; FCD, booster pump, stuffing pump, accessory homogenizer without open recirculation line all stop; separator by-passed; then FDD moves to FWD position. (HTST and HHST) 17
1.11.09.06
(H&S 2)
Time Delay Relays

CIP delay - FDD diverts; FCD, booster pump, stuffing pump, accessory homogenizer without open recirculation line all stop; separator by-passed, then FDD into CIP mode; or

FDD diverts booster pump stops, separator by-passed, 10 minute delay completed; then pumps and FDD into CIP mode. (HTST and HHST)

18
1.11.09.06
(H&S 2)
Time Delay Relays
Magnetic Flow Meter System: Time delay relay - > legal hold (15 seconds for milk). (HTST only) 28

Make space

Model space

Serial

Example of completed form for Indicating Thermometer
Task Requirements Test # Results Date Signature
1.11.10.04
1.12.03.03
1.12.04.03
1.14.10.04
1.17.10.04
(H&S 1)
Calibration/Records
Temperature accuracy (every 6 months) 1

Test T:

1. space

2. space

3. space

Indic. T:

1. space

2. space

3. space

Adjust.:

1. space

2. space

3. space

1.11.10.04
1.12.03.03
1.12.04.03
1.14.10.04
1.17.10.04
(H&S 1)
Calibration/Records
Thermometric response - 4 seconds under specified conditions. (HTST, APPS and HHST only) 2

1. space

2. space

3. space

Make space

Model space

Serial

Example #1a - Completed form for Safety Thermal Limit Recorder (STLR)
Task Requirements Test# Results Date Signature
  • 1.11.11.01
  • 1.14.11.01
    (H&S 3)
    General Conditions
Flow indicating lights operational.
1.11.11.02
(H&S 2)
Diversion Capabilities
Diversion capabilities of all products run. 6

Cut-in (A) space

Cut-out (A)space

Cut-in (B) space

Cut-out (B)space

Cut-in (C) space

Cut-out (C)space

Cut-in (D) space

Cut-out (D)space

  • 1.11.11.03
  • 1.14.11.04
  • 1.17.11.04
    (H&S 1)
    Cut In/Cut Out
  • Legal cut-in/cut-out temperatures set for all products.
  • System only goes into forward flow when the temperature is at or above pasteurization or sterilization temperature as outlined in the scheduled process. Failure of any safe forward flow condition results in the product divert device to immediately go into the divert flow position. (APPS, HHST)
6.1 & 6.2

Cut-in (A) space

Cut-out (A)space

Cut-in (B) space

Cut-out (B)space

  • 1.11.11.04
    (H & S2)
  • 1.12.05.02
  • 1.14.11.03
  • 1.17.11.03
    (H&S 3) Pens
Frequency pen and temperature pens tracking. 6
  • 1.11.11.05
  • 1.12.05.04
  • 1.14.11.03
  • 1.17.11.03
    (H&S 3) Charts
Proper charts. Chart # space
  • 1.11.11.06
  • 1.12.05.05
  • 1.14.11.05
  • 1.17.11.05
    (H&S 2)
    Accuracy
Time accuracy - equal to true elapsed time. 4

Chart Elapsed Time: space

Stopwatch Elapsed Time: space

  • 1.11.11.06
  • 1.12.05.05
  • 1.14.11.05
  • 1.17.11.05
    (H&S 2)
    Accuracy
Temperature accuracy - + 0.5°C (1°F) in specified scale range. 5

Boiling water to pasteurization T° space

Ice to pasteurization T° space

  • 1.11.11.06
  • 1.12.05.05
  • 1.14.11.05
  • 1.17.11.05
    (H&S 2)
    Accuracy
Thermometric response - 5 seconds under specified conditions. (HTST only) 7 Thermometric response space
  • 1.11.11.06
  • 1.12.05.05
  • 1.14.11.05
  • 1.17.11.05
    (H&S 2)
    Accuracy
Recording thermometer check against indicating thermometer - ≤ indicating thermometer. 3

Recording thermo. reading space

Indicator thermo. reading space

Example #1b of completed form for Safety Thermal Limit Recorder (S.T.L.R.)
Task Requirements Test # Results Date Signature
  • 1.14.11.04
  • 1.17.11.04
    (H&S 1)
    Thermal Limit Controller Sequence Logic
  • 1.14.09.04
  • 1.17.09.04
    (H&S 1)
    Fail Safe Divert Capability
  • Product divert device only moves to forward flow when all parts of the system have been properly sterilized with the minimum times and temperatures for sterilization being met (indirect and direct heating systems).
  • System only goes into forward flow when all product contact surfaces from the holding tube to the FDD have been sanitized or sterilized (HHST).
  • System only goes into forward flow when all product contact surfaces from the holding tube to the product divert device have been sterilized (APPS),
  • System only goes into forward flow when all conditions identified in the scheduled process have been met including that the sensors at the FDD and the holding tube have reached the temperature/time for pasteurization/sterilization as per the scheduled process (Indirect Heating HHST).
  • System only goes into forward flow when all the sensors located at the holding tube or other coldest point as determined by the process authority and at the FDD have reached the temperature/time for pasteurization/sterilization as per the scheduled 9 process (Direct Heating HHST).
29
Example of completed form for Heating Section
Task Requirements Test # Results Date Signature
  • 1.14.07.03
  • 1.17.07.03
    (H&S 2)
    Pressure Limit Recorder Controllers
Product divert device only moves to forward flow when the product pressure in the holding tube is at least 69 Kpa (10 psi) above the boiling pressure of the product. 30 Checked/adjusted
  • 1.14.07.03
  • 1.17.07.03
    (H&S 2)
    Pressure Limit Recorder Controllers
Product divert device only moves to forward flow when the product pressure across the injector is at least 69 Kpa (10 psi) 31 Checked/adjusted
Example #1a - Completed form for Pressure Differential Controllers (PDC)/ Gauges
Task Requirements Test # Results Date Signature
  • 1.11.12.03
  • 1.14.12.04
  • 1.17.12.04
    (H&S 2)
    Accuracy
Pressure Differential Controller - proper operation and pressure accuracy (every 6 months) 20

1st check - checked/adjusted

2nd check - checked/adjusted

  • 1.11.12.03
  • 1.14.12.04
  • 1.17.12.04
    (H&S 2)
    Accuracy
Gauges - pressure accuracy 21 Checked/adjusted
Example #1b - Completed form for Pressure Differential Controllers (PDC)/ Gauges
Task Requirements Test # Results Date Signature
  • 1.14.12.01
  • 1.17.12.01
    (H&S 2)
    General Conditions
Pressure Differential Recorder Controller interwired with product divert valve 20.1
Example of completed form for Homogenizer
Task Requirements Test # Results Date Signature
1.11.15.04
(H&S 2)
Interwiring

Homogenizer of lesser capacity than FCD, installed downstream from FCD - interwired with FCD and equipped with a time delay relay of 1 sec.

13
Example of completed form for Separator
Task Requirements Test # Results Date Signature
1.11.16.03
(H&S 2)
Properly Valved Out
Fail safe valve out to by-pass separator whenever FCD is de-energized. 13
Example of completed form for Stuffing Pump
Task Requirements Test # Results Date Signature
  • 1.11.18.02
  • 1.14.117.02
  • 1.17.17.02
    (H&S 2)
    Proper Installation/Operation
Interwired so that the pump stops when FCD not allowed to operating. 13
Example of completed form for Leak Protector Valve
Task Requirements Test # Results Date Signature
1.12.02.02
Inlet/Outlet Valves and Connections
(H&S = 2)
No leakage of milk, milk product or water past the outlet valve seat in any closed position. 32
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