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Preventive control recommendations for manufacturing fermented and dried meat products

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Introduction

The purpose of this document is to provide information on measures for controlling the risk of pathogens in fermented and dried meat products.

Control of Clostridium botulinum in fermented meat products

In order to minimize the danger of outgrowth of Clostridium botulinum spores and development of the botulinal toxin in  fermented meat products, nitrite/nitrate are added at a minimum level of 100 ppm along with a minimum of 2.5% of salt.

Control of Staphylococcus aureus in fermented meat products

Background

Certain strains of the bacteria Staphylococcus aureus are capable of producing a highly heat stable toxin that causes illness in humans. Above a critical temperature of 15.6°C, Staphylococcus aureus multiplication and toxin production can take place. Once a pH of 5.3 is reached, Staphylococcus aureus multiplication and toxin production are stopped.

Degree-hours are the product of:

Degree-hours are calculated for each temperature used in the process. The limitation of the number of degree-hours depends upon the highest temperature in the fermentation process prior to the time that a pH of 5.3 or less is attained.

The operator is encouraged to measure temperatures at the surface of the product. Where this is not possible, the operator should utilize fermentation room temperatures. The degree hour calculations are based on fermentation room temperatures. Temperature and humidity should be uniform throughout the fermentation room.

A process can be judged as acceptable provided the product consistently reaches a pH of 5.3 using:

Fermentation done at a constant temperature (Constant Temperature Process)

When fermentation is done at a constant temperature, operators can either use the following table or the calculation method (see examples below) for determining degree-hours limits and maximum time for fermentation at a given room temperature.

Table 1 Fermentation done at a constant temperature (Constant Temperature Process)
Degree-hours limit for the corresponding temperature Fermentation room temperature (°C) Maximum allowed hours to achieve a pH of 5.3
665 20 150.0
665 22 103.4
665 24 78.9
665 26 63.8
665 28 53.6
665 30 46.2
665 32 40.5
555 33 31.8
555 34 30.1
555 35 28.6
555 36 27.2
555 37 25.9
500 38 22.3
500 40 20.5
500 42 18.9
500 44 17.6
500 46 16.4
500 48 15.4
500 50 14.5

How to use the calculation method for constant temperature processes

Example 1

Fermentation room temperature is a constant 26°C. It takes 55 hours for the pH to reach 5.3.

Degrees above 15.6°C: 26°C - 15.6°C = 10.4°C
Hours to reach pH of 5.3:55
Degree-hours calculation: (10.4°C) × (55) = 572 degree-hours

The corresponding degree-hours limit (less than 33°C) is 665 degree-hours.

Conclusion: Example 1 meets the guideline because its degree-hours are less than the limit.

Example 2

Fermentation room temperature is a constant 35°C. It takes 40 hours for the pH to reach 5.3.

Degrees above 15.6°C: 35°C - 15.6°C = 19.4°C
Hours to reach pH of 5.3: 40
Degree-hours calculation: (19.4°C) × (40) = 776 degree-hours

The corresponding degree-hours limit (between 33 and 37°C) is 555 degree-hours.

Conclusion: Example 2 does not meet the guideline because its degree-hours exceed the limit. Hold the product and refer to Disposition of lots which have not met degree-hours limits below.

Fermentation done at different temperatures (Variable Temperature Process)

When the fermentation takes place at various temperatures, each temperature step in the process is analyzed for the number of degree-hours it contributes. The degree-hours limit for the entire fermentation process is based on the highest temperature reached during fermentation.

Example 1

It takes 35 hours for product to reach a pH of 5.3 or less. Fermentation room temperature is 24°C for the first 10 hours, 30°C for second 10 hours and 35°C for the final 15 hours.

Step 1

Degrees above 15.6°C: 24°C - 15.6°C = 8.4°C
Hours to reach pH of 5.3: 10
Degree-hours calculation: (8.4°C) × (10) = 84 degree-hours

Step 2

Degrees above 15.6°C: 30°C - 15.6°C = 14.4°C
Hours to reach pH of 5.3: 10
Degree-hours calculation: (14.4°C) × (10) = 144 degree-hours

Step 3

Degrees above 15.6°C: 35°C - 15.6°C = 19.4°C
Hours to reach pH of 5.3: 15
Degree-hours calculation: (19.4°C) × (15) = 291 degree-hours

Degree-hours calculation for the entire fermentation process = 84 + 144 + 291 = 519

The highest temperature reached = 35°C

The corresponding degree-hour limit = 555 (between 33°C and 37°C)

Conclusion: Example 1 meets the guideline because its degree-hours are less than the limit.

Example 2

It takes 38 hours for product to reach a pH of 5.3 or less. Fermentation room temperature is 24°C for the first 10 hours, 30°C for the second 10 hours and 37°C for the final 18 hours.

Step 1

Degrees above 15.6°C: 24°C - 15.6°C = 8.4°C
Hours to reach pH of 5.3: 10
Degree-hours calculation: (8.4°C) × (10) = 84 degree-hours

Step 2

Degrees above 15.6°C: 30°C - 15.6°C = 14.4°C
Hours to reach pH of 5.3: 10
Degree-hours calculation: (14.4°C) × (10) = 144 degree-hours

Step 3

Degrees above 15.6°C: 37°C - 15.6°C = 21.4°C
Hours to reach pH of 5.3: 18
Degree-hours calculation: (21.4°C) × (18) = 385.2 degree-hours

Degree-hours calculation for the entire fermentation process = 84 + 144 + 385.2 = 613.2

The highest temperature reached = 37°C

The corresponding degree-hour limit = 555 (between 33°C and 37°C)

Conclusion: Example 2 does not meet the guidelines because its degree-hours exceed the limit; hold the product and refer Disposition of lots which have not met degree-hours limits below.

Disposition of lots which have not met degree-hours limits

When an operator is conducting a product risk assessment because they intend to distribute a product for which the degree-hours limit has been exceeded, consideration should be given to the following:

E. coli and Salmonella control options in fermented sausages

In order to suitably control these hazards and prevent incidents of food borne disease, facilities who manufacture fermented sausages can use one of the five following options for the control of verotoxinogenic E. coli including E. coli O157:H7 and Salmonella when they:

Facilities which do not use beef and do not obtain meat ingredients from facilities which handle beef are not currently required to use one of the five options for the control of E. coli O157:H7 in dry/semi-dry fermented sausages. However, they must validate through a microbiological testing program that their process will not result in the presence of E. coli O157:H7 or Salmonella in the finished product.

Option 1

Include as part of the manufacture of the sausage, one of the following heat processes which are recognized as controlling E. coli O157:H7.

Note: Under this option, it is not required to test for E. coli O157:H7.

Table 2 Heat processes recognized as controlling Escherichia coli O157:H7
Minimum internal temperature maintained during the entire process Minimum processing time in minutes after the minimum temperature has been reached
130°F (54.4°C) 121
131°F (55°C) 97
132°F (55.6°C) 77
133°F (56.1°C) 62
134°F (56.7°C) 47
135°F (57.2°C) 37
136°F (57.8°C) 32
137°F (58.4°C) 24
138°F (58.9°C) 19
139°F (59.5°C) 15
140°F (60°C) 12
141°F (60.6°C) 10
142°F (61.1°C) 8
143°F (61.7°C) 6
144°F (62.2°C) 5
145°F (62.8°C) 4

Option 2

Use a manufacturing process (combination of fermentation, heating, holding and/or drying) which has already been scientifically validated to achieve a 5 log10 (5D) reduction of E. coli O157:H7.

Manufacturing processes used to make fermented sausages are only considered effective against E. coli O157:H7 if it is shown that they achieve a 5 log10 (5D) reduction or greater of E. coli O157:H7. The manufacturing process used is evaluated in a scientific manner consistent with the challenge study recommendations (refer to Option 5) of this section.

Under this option, testing each lot for E. coli O157:H7 or Salmonella is not needed. The operator will implement a microbiological testing program for E. coli 0157 and Salmonella as a verification procedure for their process.

The following processes have been scientifically validated as achieving a 5 log10 (5D) or greater reduction of E. coli O157:H7.

Table 3 How to achieve a 5 log10 (5D) or greater reduction of Escherichia coli O157:H7
Fermentation chamber temperature pH at the end of fermentation process Casing diameter Subsequent process (dry, hold or cook) Reference
70°F (21°C) > 5.0 < 55 mm heat (1 hr @ 110°F and 6 hrs @ 125°F)

Table Note 1

90°F (32°C) < 4.6 < 55 mm hold @ 90°F for > 6 days

Table Note 1

90°F (32°C) < 4.6 < 55 mm heat (1 hr @ 110°F then 6 hrs @ 125°F)

Table Note 1

90°F (32°C) < 4.6 56 to 105 mm heat (1 hr @100°F, 1 hr @ 110°F, 1 hr @ 120°F, then 7 hrs @ 125°F)

Table Note 1

90°F (32°C) > 5.0 56 to 105 mm heat (1 hr @100°F, 1 hr @ 110°F, 1 hr @ 120°F, then 7 hrs @ 125°F)

Table Note 1

96°F (36°C) < 5.0 < 55 mm heat (1 hr @ 128°F internal product temperature) and dry (at 55°F and 65% relative humidity to a moisture protein ratio of < 1.6:1)

Table Note 2

110°F (43°C) < 4.6 < 55 mm hold @ 110°F for > 4 days

Table Note 1

110°F (43°C) < 4.6 56 to 105 mm hold @ 110°F for > 4 days

Table Note 1

110°F (43°C) > 5.0 56 to 105 mm hold @ 110°F for > 7 days

Table Note 1

Table Notes

Table note 1

Nicholson, R., et al, Dry fermented sausage and Escherichia coli O157:H7. National Cattlemen's Beef Association, Research Report Number 11-316, Chicago, Illinois, 1996.

Return to table note 1  referrer

Table Note 2

Hinkens, J.C., et al, Validation of Pepperoni Processes for Control of Escherichia coli O157:H7, Journal of Food Protection, Volume 59, Number 12, 1996, pp. 1260-1266.

Return to table note 2  referrer

Option 3

Where the manufacturing process does not correspond to one of the processes set out under options 1, 2 or 4 of this section and has not been assessed in accordance with option 5 of this section, hold and test each production lot pending satisfactory results.

Option 4

This option entails a microbiological testing program of raw meat and batter for E. coli O157:H7 and Salmonella as part of the operator's HACCP-based system and a manufacturing process (fermentation and holding, heating and/or drying) which has been scientifically validated as achieving at least 2 log10 (2D) reduction of E. coli O157:H7.

Manufacturing processes used to make fermented sausages are considered partially effective against E. coli O157:H7 if it is shown that they achieve 2 log10 (2D) reduction to 5 log10 (5D) reduction of E. coli O157:H7. The manufacturing process used is evaluated in a scientific manner consistent with the challenge study recommendations (refer to Option 5). A number of manufacturing processes have been scientifically demonstrated as achieving a 2 log10 (2D) reduction to 5 log10 (5D) reduction. The sampling program must be in accordance with the following requirements:

Table 4 How to achieve a minimum 2 log10 (2D) reduction in Escherichia coli O157:H7
Fermentation chamber temperature pH at the end of fermentation Casing diameter Subsequent process (dry, hold or cook) Reference
70°F (21°C) > 5.0 56 to 105 mm heat(1 hr @ 110°F and 6 hours @ 125°F)

Table Note 3

90°F (32°C) < 4.6 56 to 105 mm hold @ 90°F for 7 days then dry

Table Note 3

90°F (32°C) > 5.0 56 to 105 mm hold @ 90°F for 7  days then dry

Table Note 3

110°F (43°C) > 5.0 < 55 mm hold @ 110°F for 7 days then dry

Table Note 3

110°F (43°C) > 5.0 56 to 105 mm heat (1 hr @ 110°F and 6 hours @ 125°F)

Table Note 3

Table Note

Table note 3

Nicholson, R., et al, Dry fermented sausage and Escherichia coli O157:H7. National Cattlemen's Beef Association, Research Report Number 11-316, Chicago, Illinois, 1996.

Return to table note 3  referrer

Option 5

This option is a validation challenge study to demonstrate that the manufacturing process achieves as 5 log10 (5D) reduction of E. coli O157:H7.

Facilities which elect to use this option to demonstrate that their manufacturing process achieves a 5 log10 (5D) reduction of E. coli O157:H7, may be able to manufacture product according to the requirements of Option 2 (e.g., not be required to test each lot of product for E. coli O157:H7 and Salmonella). Alternatively, if their manufacturing process achieves a 2 log10 (2D) reduction of E. coli O157:H7 they may be able to manufacture product according to the requirements of Option 4 (e.g., HACCP-based system and testing of raw batter).

Challenge Study Protocol

Control of pathogens in dried products

This form of preservation depends on a lowering of the water activity (aw) of the product to inhibit the growth of microorganisms through, for instance, freeze drying or salting. It should be considered that a reduction in water activity neither destroys microorganisms nor toxins; it only retards the growth of microorganisms. Therefore, the operator should have controls in place to assess the incoming product.

Control of E. coli O157 in dried beef products

As dried beef products may pose a hazard associated with E. coli O157:H7, these products must be submitted to a heat treatment before the drying process.

The following methods have been found acceptable for this purpose:

Shelf stable fermented and dried meat products

In accordance with Safe Food for Canadians Regulations 286, fermented and dried products are considered "shelf stable" and do not require refrigeration if:

  1. The pH of the finished product is of 4.6 or less, regardless to its final aw; or
  2. The aw of the finished product is 0.85 or less, regardless of its final pH.

A fermented meat product is also considered shelf stable if the pH is 5.3 or lower at the end of the fermentation period and the end product has an aw of 0.90 or lower.

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