Dairy Vitamin Addition

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1. Background

Addition of Vitamin A, Vitamin C and Vitamin D to fluid milk is a legal requirement under Health Canada's Food and Drugs Act (see Appendix 1, Table 1). Vitamin D is added to all forms of milk while Vitamin A is added only to skim and partly (partially) skimmed milks. Evaporated and powdered milks which are sold at retail in Canada have similar requirements for vitamin addition. In addition, Vitamin C is required to be added to evaporated milks. Section B.08.027 of the Food and Drug Regulations (FDR) exempts certain dairy products which are used in or sold for the manufacture of other food from the vitamin addition requirements which are specified in the above prescribed food standards

Vitamin A serves several functions in the human body. It is required to maintain vision, a healthy immune system, cell and bone growth, and fertility. Vitamin A occurs naturally only in animal products. It is a fat-soluble vitamin so is concentrated in the fat portions of animals and therefore is quite abundant in milk fat. Vitamin A is removed with the fat during the separation process in skim and partly (partially) skimmed milks, thus making it a requirement to replenish the lost vitamin in the form of a vitamin premix. Whole (homogenized) milk does not go through the separation process and therefore the naturally occurring Vitamin A is maintained and fortification is not required. A deficiency in Vitamin A can commonly lead to dry skin and night blindness. More severe deficiencies can lead to anemia, reduced growth, permanent blindness or liver damage.

Vitamin D functions to increase mineral content of bones, assists in the absorption of calcium and phosphorus and helps to conserve minerals in the kidney. The central source of Vitamin D is sunshine. Ultraviolet (UV) rays act to convert a chemical naturally occurring in the skin (7-dehydrocholesterol) into Vitamin D in the liver and kidneys. The main food sources are from eggs, liver and small fish. The deficiency of Vitamin D can lead to bone disease (Rickets in children and Osteomalacia in adults) therefore the main goal of milk fortification with Vitamin D is to prevent such diseases. Rickets is identified by a bow-legged appearance and/or lumps on the ribs in children due to poor bone formation. A deficiency of Vitamin D leads to low calcium absorption and softening of the bones, resulting in the above described features.

Vitamins A and D both have quite narrow ranges of safety which when exceeded can result in toxicity symptoms. The close regulation of milk fortification with Vitamins A and D is extremely important to ensure that the correct amount of vitamin is used. Too little can result in deficiency symptoms as described above but over-fortification can be toxic and in severe cases, can result in death. In Vitamin A toxicity, death is most often due to liver failure and death due to Vitamin D toxicity is most often because of kidney failure.

Vitamin C was originally added to evaporated milk to supplement the diets of people who often lived in isolated communities and did not have access to fresh fruit and vegetables. Vitamin C, a water-soluble vitamin, is important in forming collagen, a protein that gives structure to bones, cartilage, muscle, and blood vessels. Vitamin C also helps maintain capillaries, bones, and teeth and aids in the absorption of iron. Water-soluble vitamins taken in excess are excreted in the urine and are not usually associated with toxicity. Toxic consequences of over fortification with Vitamin C may include gastrointestinal effects, diarrhea and flatulence.

2. Objective of Activity

To ensure that fluid, evaporated and dry milks offered for retail sale in Canada are in compliance with the mandatory requirements of the Food and Drugs Act and Regulations with respect to vitamin addition.

3. Scope

This activity when performed by Canadian Food Inspection Agency (CFIA) inspection staff verifies that mandatory vitamin fortification and/or vitamin addition in the registered establishments complies with the requirements of the Food and Drugs Act and Regulations. Inspections include milk products with Vitamin A, C and D additions. This activity is not conducted in establishments that are HACCP recognized. Verification of the addition of calcium containing modified milk ingredients for the purpose of increasing the calcium content of dairy products is covered in Dairy Ingredient Verification.

4. Required Equipment/References

Food and Drugs Act and Regulations (FDA/R)
Calculator
Vitamin Addition Worksheet
Dairy Inspection Report (CFIA/ACIA 950)
Dairy Establishment Inspection Manual (DEIM)

5. Inspection Procedures

The vitamin addition process will be inspected to ensure the establishment complies with the following criteria. This information is recorded on the worksheet (see Appendix 2).

Definitions

Vitamin Premix
is a vitamin preparation supplied to a commercial processor, to be used in the fortification of fluid milk, instant milk powder and evaporated milk products as supplied or as a part of a vitamin solution. Vitamin premixes are available as liquid concentrates, powders or beads
Vitamin Solution
is a blend of a vitamin premix and a suitable diluent

5.1 Raw Materials

a) The establishment must have written specifications for vitamin premixes (includes liquid concentrates, powders and beadlets) which specify the supplier, potency, form and stability.

b) Footnote 1The establishment must ensure that the vitamin premix meets the established specifications either through a certificate of analysis from the supplier or sampling and analysis by the establishment. If the vitamin premixes are a combination of vitamin A and D in a milk powder carrier, the establishment must be sure (guarantee or micro analysis i.e. SPC/AAC, Coliforms, Salmonella) that the carrier powder is not contaminating the finished product.

c) Vitamin premixes must be stored according to the manufacturer's specifications. Once opened, these premixes are used before the expiry date to prevent loss of potency. Vitamin D is light sensitive and therefore loses potency if stored in clear containers exposed to light.

5.2 Preparation of Vitamin Solutions

a) Footnote 1The theoretical calculation for preparing vitamin solutions by the establishment should aim for finished product vitamin target levels, mid-range of regulatory requirements, (see Appendix 1, Table 2) and also allow for seasonal variations, processing variables such as rework which may contain previously added vitamins, and the shelf-life of the product. Some examples of theoretical calculations can also be found in Appendix 1.

b) Written instructions for preparing vitamin solutions based on the theoretical calculations, should be posted in the preparation area.

c) The persons responsible for preparing the vitamin solution should be trained and knowledgeable in such procedures.

d) In order to assure accuracy of measurement, the establishment uses appropriate measuring devices (graduated cylinders or syringes) and of sufficient sensitivity for the dilution being performed. e.g. a 1000 ml graduated cylinder would not be used to measure 10 ml of vitamin premix.

e) Footnote 1Dry vitamin mixes must be prepared according to the supplier's direction and maintained in solution throughout the production. Constant agitation (e.g. with a magnetic stir bar and plate) may be required to prevent settling.

f) Footnote 1Vitamin solutions must be prepared just prior to use and, when not in use, must be stored in such a manner as to minimize loss of vitamin potency, preferably in insulated vessels; 4°C. Storage time must be kept to a minimum, no longer than 24 hours. Left-over solution at the end of the day must be discarded and not reused.

g) Containers of vitamin premix and vitamin solutions must be properly identified as to their contents and use. The use of laminated tags or such is recommended over markers. Containers and equipment used for dilution should be cleaned and sanitized daily, or more frequently, if necessary.

5.3 Vitamin Addition

Vitamin addition can be accomplished at different points in the processing system. These range from addition to the batch pasteurizer, to the high temperature short time (HTST) pasteurizer balance tank, by a batch method to a blender of finished powder prior to final packaging or on a continuous flow method, to finished powder prior to final sifting.

5.3.1 Continuous Flow Method

a) Footnote 1To avoid changing pump settings, vitamin solutions may be prepared in concentrations that will allow the use of a single feed rate for all products. If, however, the pump is of a variable speed type, then provisions should exist for either locking the setting or for regularly recorded checks to ensure that unauthorized adjustments are not made. A change in the pump speed (flow rate) alters the calculations for the amount of vitamin required and would result in an inaccurate amount of vitamin being added.

A positive displacement type pump must be used. Otherwise negative pressures at the point of injection can create problems. A small vacuum can result in relatively large volumes of vitamin concentrates being drawn into a milk system in a very short time period. There are two types of positive placement pumps available. One is a piston type positive displacement metering pump without valves. It is equipped with a micrometer, which allows accurate and reproducible amounts of vitamins to be added based on the rate of product flow through the system. The other type of positive displacement pump is a peristaltic pump which offers precise control. This is because the volume can be controlled by the size of the tubing used and pump speed.

b) The establishment should prepare a suitable excess of vitamin solution to prevent the possibility of running out of solution before the end of the production run. The amount of vitamin solution not used should be measured, recorded and taken into consideration in calculating the levels of enrichment in item 4.1. In most cases a 10% excess is suitable.

c) The vitamin solution should be added after separation, where applicable, but before pasteurization. During separation, any fat soluble vitamins would be removed with the fat therefore if added before separation, would be wasted and not reach the finished product (in the cases of skim and partly (partially) skimmed milks). For manufacturers who purchase water soluble vitamin solutions these could be added before separation as these would not be removed with the fat. The vitamin solutions are not sterile, therefore must be added prior to pasteurization. The best point of injection is ahead of the homogenizer, which in most cases is the point of low pressure. This allows the homogenization process to distribute vitamin(s) throughout the milk.

d) Footnote 1The vitamin pump should be installed:

  • with the injector site located at a point in the production line where minimal pressure fluctuation occurs;
  • with a line (food-grade tubing), from the pump to processing line, of minimal length and of transparent material to be able to observe the flow bubbles etc. which might prevent the flow of vitamins into the product; and,
  • in such a manner that the pump operates only when the pasteurizing unit is in forward flow and does not function when the system is in divert. The two must be inter-wired such that when the pasteurizer switches to divert, the solution pump shuts off and when the pasteurizer switches back into forward flow, the solution pump comes on again.

e) The vitamin pump and pipelines are clean and in good condition. Inspector can assess this by reviewing the establishment's sanitation and maintenance records for the equipment. During the annual indepth inspection the inspector will verify condition of equipment in the dismantled state and rate under tasks DEIM 1.25.0.2107 (Pumps) and 1.25.0.2108 (Pipelines and Valves).

f) Footnote 1The vitamin delivery system must be checked at start up and after changeovers for leaks, air locks and correct feed rate setting by the person responsible. Records of these checks and any corrective actions must be maintained.

g) Footnote 1The level of vitamin solution in the vitamin solution reservoir must be checked and recorded at least hourly, to ensure the amount of vitamin solution is being used at a consistent rate and will not run out before the end of production run. Any further addition of vitamin solution to the reservoir must be recorded. Any problems such as leaks, air locks etc. should be noted on the record with the time and the action taken to resolve it.

h) The establishment must have a written contingency plan which can be implemented in the event that the vitamin pump or other parts of the vitamin delivery system fail. Production does not continue without the effective vitamin fortification.

5.3.2 Batch Method

a) Vitamin addition should take place after separation but before pasteurization for the afore mentioned reasons.

b) Footnote 1After addition of vitamin solution, the milk should be agitated sufficiently to ensure homogeneity. The batch procedure requires accurate measurement of the volume of milk to be fortified and accurate measurement of the vitamin concentration.

5.3.3 Continuous Flow Method - Dry Powdered Premix added to Finished Powder

a) Footnote 1Prior to start up the volumetric feeder is calibrated to consistently deliver the desired amount of vitamin premix. Provisions should exist for either locking the setting or for regularly recorded checks to ensure that unauthorized adjustments are not made. A change in the flow rate alters the calculations for the amount of vitamin required and would result in an inaccurate amount of vitamin being added.

b) Footnote 1The amount of vitamin premix added to hopper at start up and during production is recorded. Product left in the hopper at the end of production should be weighed out. Values will be used to determine the calculated value.

c) Footnote 1The level of vitamin premix in the hopper is checked on a regular basis (hourly) to ensure hopper does not run out of vitamin premix or a low level alarm installed. A record of these checks must be kept. Unusual occurrences and action taken are also documented.

d) Vitamin premix added prior to final sifting. Vitamins are added to milk powders in this fashion (post drying) as the heat of evaporation and drying destroy the vitamins. A mix step is necessary to ensure homogeneity.

e) The operator must ensure that the volumetric feeder operates only when the system is in forward flow.

f) The establishment must have a written contingency plan which can be implemented in the event that the vitamin delivery system fails. Production must not continue without the effective vitamin fortification.

5.3.4 Batch Method - Dry Powdered Premix added to Finished Powder

a) Footnote 1The amount of vitamin premix added to the blender containing a premeasured amount of milk powder, is calculated and recorded. The amount of premix added depends on the size of the batch.

b) Footnote 1After the addition of vitamin premix, the milk powder should be agitated sufficiently to ensure homogeneity. The batch procedure requires accurate measurement of the amount of milk powder to be fortified and accurate measurement of the vitamin concentration.

5.4 Finished Product Evaluation: Quality Control

In order to verify the quantity of vitamin(s) in the finished product, the establishment must maintain records and perform laboratory analysis as outlined below.

a) Footnote 1Records - After the production of each product, records must be made of:

  • name of product, production code and/or best before date of the product
  • the total amount of vitamin solution prepared
  • the amount of vitamin solution used
  • the amount of product produced
  • the calculated amount of vitamin in the product based on the vitamin solution consumption (See Appendix 1 for examples)
  • re-work (e.g. for chocolate milk production)
  • a record should be kept to track amount of rework and amount of fresh milk used. The re-work will have already had vitamin added whereas the fresh will require fortification.

b) Footnote 1Analysis - Vitamin analysis should be performed by an accredited laboratory. All enriched products must be sampled and analyzed at least monthlyFootnote 2 and more frequently if deviations are encountered. It is recommended that establishments draw three samples, one from the beginning, middle and end of the production run.

c) Footnote 1Review - On a daily basis, the establishment should compare calculated values and theoretical values to ensure correlation (see examples in Appendix 1). Significant differences, whether inside or outside legal requirements, should be investigated and corrective action documented. The calculated values should also be compared with the lab analysis. A considerable range can be expected between these two values due to several factors (storage temperature of samples, method differences and errors etc.) It is recommended to look for trends between the two values rather than equivalent values.

5.5 Sampling

Since lab analyses are expensive, the laboratories usually request several samples at the same time (typically within a two-week period) to cut down on these costs. Sampling by CFIA, is usually done annually except in the situations where there is a history of non-compliance.

For the monitoring program, each specimen consists of three subsamples, minimum one litre in size. If one-litres were not packaged at the plant, take three 1.33 L pouches. Five subsamples are required for compliance or legal sampling. The subsamples should represent the entire lot so inspectors should make every effort to obtain samples from the beginning, middle and end of the production end and identify the subsamples as such. Lab results will be reported in a manner which will allow the inspector to evaluate the vitamin addition capability at the beginning, middle and end of the production run. Be sure to backfill the crates if sampling from the cooler so orders are sent out intact with no missing units.

When sampling, it is best to take most recent production. Target any product that would be most adversely affected by the process. As an example, this would mean taking skim milk for Vitamin A analysis, as it would have the least naturally occurring vitamin and therefore would give the best indication of the efficiency of the fortification system. For Vitamin D, it is best to take homogenized (whole) milk. Specimens should be well identified and packaged. Wrap individual containers in a double plastic bag, milk can still be analyzed if it has leaked so long as it remains contained in its plastic bag. For milk in cardboard cartons, wrap in paper towels prior to placing in plastic bags to absorb any condensation. Pack well with newspaper and cooler packs in a styrofoam container; do not freeze.

6. Overall Vitamin Inspection Assessment

An inspection will be considered non-satisfactory if an establishment receives one non-satisfactory rating in any of the inspection tasks identified with a footnoteFootnote 1. These tasks are considered to have a potential impact on the vitamin levels in finished product and therefore require 100% compliance. The overall vitamin addition assessment is to be noted on the CFIA/ACIA 950.

6.1 Satisfactory Inspections

Even if the vitamin inspection is assessed as satisfactory the outstanding issues will still need to be noted on the CFIA/ACIA 0950 form with agreed upon corrective action dates for all non-satisfactory tasks. The plant is required to submit corrective action dates even though the inspection may be considered satisfactory. The follow-up to the correction would then be done on a subsequent inspection. If the inspector so chooses he or she may want to request the establishment to respond in a letter outlining their intended plan of action which should be received no later than 3 weeks from the inspection date.

6.2 Non-Satisfactory Inspections

Actions to be taken for non-satisfactory inspections will be based on the severity of the findings and/or level of responsibility taken by the plant. The impact of the deficiency must be evaluated to determine if human health and safety has been compromised over the long or short term.

For the following scenarios, it is important that the inspector inform the appropriate Program Specialist in order to jointly determine the action to be taken:

a) Critical health and safety implications

This could be due to the non-satisfactory evaluation of tasks such as the preparation of vitamin solutions and/or errors in the vitamin addition method resulting in overages of vitamin levels in the finished product. Immediate action must be taken to isolate affected product manufactured during the occurrence of the problem. Any affected product still remaining in the establishment should be detained as per Detention and Release Procedures. Product suspected of containing excessive amounts of Vitamin A and D will have to undergo laboratory analysis in order to determine the safety of the product. If the product has been distributed, the inspector should immediately contact the appropriate Program Specialist with the relevant details to determine if a product recall is necessary as per the recall protocol.

In addition to controlling the affected product, the establishment must also take the appropriate measures (e.g. training,reviewing written procedures) to prevent the problem from re-occurring.

The establishment is to provide a response letter outlining their intended plan of action (how and when the noted deficiencies will be corrected) and the measures taken to prevent the problem from re-occurring, which is to be received no later than 3 weeks from the inspection date.

b) Non-critical health and safety infractions

This is indicated by a non-satisfactory evaluation of a task or procedure that does not result in repetitive underages or overages of vitamin(s) in the finished product. Any inspection task rated as Non-Satisfactory must be corrected within appropriate time frames.

The establishment is to provide a response letter outlining their intended plan of action (how and when the noted deficiencies will be corrected) and the measures taken to prevent the problem from re-occurring, which is to be received no later than 3 weeks from the inspection date.

c) Non-satisfactory laboratory results (Dairy Sampling Procedures)

Values outside legal requirements should be investigated during a follow-up visit by the inspector. During this visit the inspector should review the calculated values and the lab analysis for the lot in question as well as lots produced around the same time. The inspector should also review the handling and storage of the vitamin premix and review the finished product laboratory analysis results carried out by the establishment. Any product suspected of containing an overage of Vitamin A and/or D which may still be at the establishment should be detained. If the product has been distributed, the inspector should immediately contact the appropriate Program Specialist with the relevant details to determine if a product recall is necessary as per the recall protocol. Additional samples should be taken to assist in the investigation.

The establishment is to provide a response letter outlining their intended plan of action (how and when the noted deficiencies will be corrected) and the measures taken to prevent the problem from re-occurring, which is to be received no later than 3 weeks from the inspection date.

Appendices

Appendix 1

Table 1

Mandatory Vitamin Fortification for Dairy Products as per FDR based on Recommended Daily Intake (RDI) [Schedule K]
Common name Standard Vitamin D (IU) Vitamin A (IU) Vitamin C (mg)
Milk (Whole) B.08.003 300-400 N/A N/A
Milk (naming the flavour) B.08.016 300-400 N/A N/A
Milk Powder (Whole/Dry) B.08.013 300-400 N/A N/A
Sterilized Milk B.08.007 300-400 N/A N/A
Skim Milk B.08.004 300-400 1200-1500 N/A
Skim Milk with Added Milk Solids B.08.019 300-400 1200-2500 N/A
Skim Milk (naming the flavour) B.08.017 300-400 1200-2500 N/A
Skim Milk with Added Milk Solids (naming the flavour) B.08.023 300-400 1200-2500 N/A
Partly (Partially) Skimmed Milk B.08.005 300-400 1200-2500 N/A
Partly (Partially) Skimmed Milk (naming the flavour) B.08.018 300-400 1200-2500 N/A
Partly (Partially) Skimmed Milk with Added Milk Solids B.08.020 300-400 1200-2500 N/A
Partly (Partially) Skimmed Milk with Added Milk Solids (naming the flavour) B.08.026 300-400 1200-2500 N/A
Skim Milk Powder (Dry) B.08.014 300-400 1200-2500 N/A
Condensed Milk (Sweetened) B.08.009 optional N/A N/A
Evaporated Milk B.08.010 300-400 N/A 60-75
Evaporated Skim Milk (Concentrated) B.08.011 300-400 1200-2500 60-75
Evaporated Partly Skimmed Milk (Concentrated) B.08.012 300-400 1200-2500 60-75
Various Goat's Milk Products B.08.029 optional optional optional

Table 2

Target Fortification Levels for Fluid Milks, Reconstituted Dry Milk, Reconstituted Evaporated Milks
Vitamin Range Target Level
A 140.8 - 293 IU/100 ml 216.9 IU/100 ml
D 35.2 - 46.9 IU/100 ml 41.0 IU/100 ml
C 140.8 - 17.6 mg/100 ml 15.84 mg/100 ml

The appropriate vitamin fortification target level is taken at mid-range for the acceptable level.

Appendix 2

Calculations

Theoretical Values

A) Batch Method:

T = VC/Q

Where,
T = Theoretical Concentration of Vitamin in the Final Product (IU/100 ml)
V = Volume of Vitamin Premix used (ml)
C = Concentration of Vitamin Premix (IU/ml)
Q = Quantity of Milk to be Fortified (ml)Footnote 3

Example:

T = Theoretical Concentration of Vitamin in the Final Product (IU/100 ml)
V = 3.35 ml
C = 205,000 IU/ml (of Vitamin D)
Q = 1800 L (1800 L × 1000 ml/L = 1,800,000 ml)

T = VC/Q
T = [(3.35 ml) × (205,000 IU/ml)] ÷ 1,800,000 ml
T = 686,750 IU ÷ 1,800,000 ml
T = 0.3815 IU/ml of Vitamin D

This needs to be converted to IU/100 ml
Therefore: (0.3815 IU/ml) × (100 ml) = 38.15 IU/100 ml
T = 38.15 IU/100 ml of Vitamin D

B) Continuous Flow Method

T = CP/F

Where,
T = Theoretical Concentration of Vitamin in the Final Product (IU/100ml)
C = Concentration of Vitamin Premix (or concentration of diluted Vitamin solution) (IU/ml)
P = Vitamin Pump Speed (ml/minute)
F = Flow rate of milk (ml/minute)Footnote 4

If the vitamin premix is diluted prior to its addition to the milk, the concentration of this diluted solution must be determined before filling it into the formula. To determine the concentrate use the following:

Concentration of diluted vitamin solution (IU/ml) = [(Concentration of Vitamin Premix (IU/ml)) × (Volume of Vitamin Premix used (ml))] ÷ Volume of diluted Vitamin Solution to be prepared (ml).

Example:

When Vitamin Premix is not diluted

T = Theoretical Concentration of Vitamin in the Final Product (IU/100ml)
C = 95,000 (IU/ml) (of Vitamin A)
P = 7.0 (ml/minute)
F = 292 L/minute (292 L/minute × 1000 ml/L = 292,000 ml/minute)

T = CP/F
T = [(95,000 IU/ml) × (7.0 ml/minute)] ÷ (292 ml/minute)
T = (665,000 IU/minute) ÷ (292,000 ml/minute)
T = 2.277 IU/ml of Vitamin A

This needs to be converted to IU/100 ml.
Therefore:
(2.277 IU/ml) × (100 ml) = 228 IU/100 ml
T = 228 IU/100 ml of Vitamin A

When Vitamin Premix is diluted

First, determine the Concentration of the diluted Vitamin solution:

Concentration of diluted vitamin solution (IU/ml) =
[(Concentration of Vitamin Premix (IU/ml)) × (Volume of Vitamin Premix used (ml))] ÷ Volume of diluted Vitamin Solution to be prepared (ml).

Where,
Concentration of Vitamin Premix [IU/ml] = 205,000 IU/ml (of Vitamin D)
Volume of Vitamin Premix used [ml] = 24 ml
Volume of diluted Vitamin Solution to be prepared [ml] = 500 ml

Concentration of diluted vitamin solution (IU/ml) =
[(Concentration of Vitamin Premix (IU/ml)) × (Volume of Vitamin Premix used (ml))] ÷ Volume of diluted Vitamin Solution to be prepared (ml) =
(205,000 IU/ml × 24 ml) ÷ 500 ml = 9840 IU/ml.

Then use this value for "C" in the formula T= CP/F

T = Theoretical Concentration of Vitamin in the Final Product (IU/100 ml)
C= 9840 IU/ml
P = 2.6 (ml/minute)
F = 64 L/minute (64 L/minute × 1000 ml/L = 64,000 ml/minute)

T = CP/F
T = (9840 IU/ml × 2.6 ml/minute) ÷ 64,000 ml/minute
T = 25,584 IU/minute ÷ 64,000 ml/minute
T = 0.39975 IU/ml of Vitamin D

This needs to be converted to IU/100 ml.
Therefore: (0.39975 IU/ml) × (100 ml) = 39.975 IU/100 ml
T = 39.975 IU/100 ml of Vitamin D

Calculated Values

CV = C U/Q

Where,
CV = Calculated level of vitamins in final product (IU/ml)
C = Vitamin Premix Concentration (or concentration of diluted Vitamin solution) (IU/ml)
U = Total volume of Vitamin Premix used (or volume of diluted Vitamin solution) (ml)
Q = Total Quantity of fortified finished product (ml)Footnote 5

Examples:

When Vitamin Premix is not diluted

CV = Calculated level of vitamins in final product
C = 50,000 IU/ml (of Vitamin A)
U = 64.8 ml
Q = 1810 L (1810 L × 1000 ml/L = 1,810,000 ml)

CV = C U/Q
CV = [(50,000 IU/ml) × (64.8 ml)] ÷ 1,810,000 ml
CV = 3,240,000 IU/1,810,000 ml
CV = 1.79 IU/ml of Vitamin A

This needs to be converted to IU/100 ml.
Therefore: (1.79 IU/ml) × (100 ml) = 179 IU/100 ml
T = 179 IU/100 ml of Vitamin A

When Vitamin Premix is diluted.

CV = Calculated level of vitamins in final product (IU/100 ml)
C = Vitamin Premix Concentration (IU/ml)
U = Total volume of Vitamin Premix used (ml)
Q = Total Quantity of fortified finished product (ml)Footnote 6

Where,
Concentration of Vitamin Premix [IU/ml] = 205,000 IU/ml (of Vitamin D)
Volume of Vitamin Premix used [ml] = 126.2 ml
Volume of diluted Vitamin Solution to be prepared [ml] = 7.6 ml
7.6 L × 1000 ml/L = 7600 ml

Concentration of diluted vitamin solution (IU/ml) =
[(Concentration of Vitamin Premix (IU/ml)) × (Volume of Vitamin Premix used (ml))] ÷ Volume of diluted Vitamin Solution to be prepared (ml) =
[(205,000 IU/ml) × (126.2 ml)] ÷ 7600 ml =
258,710,000 IU ÷ 7600 ml =
3404.1 IU/ml.

Then use this value for "C" in the formula CV = C U/Q

CV = Calculated level of vitamins in final product (IU/ml)
C = 3404.1 IU/ml
U = 7560 ml
Q = 60,586 L (60.586 L × 1000 ml/L = 60,586,000 ml)

CV = C U/Q
CV = [(3404.1 IU/ml) × (7560 ml)] ÷ 60,586,000 ml
CV = 25,734,996IU/60,586,000 ml
CV = 0.425 IU/ml of Vitamin D

This needs to be converted to IU/100 ml.
Therefore: (0.425 IU/ml) × (100 ml) = 42.5 IU/100 ml
T = 42.5 IU/100 ml of Vitamin D

Sometimes, solutions may be prepared by weighing the premix instead of using a volumetric measure. In order to convert the weight of premix to a volume, you need to know the Specific Gravity (density) of the premix.

Use the formula V = M ÷ SG where

V = Amount of vitamin premix used (ml)
M = Weight of premix used (g)
SG = Specific Gravity (density) of premix (g/ml)

Example Calculation

V = Amount of vitamin premix used (ml)
M = Weight of premix used (3.5 g)
SG = Specific Gravity (density) of premix (1.045 g/ml)

Use the formula V = M ÷ SG (3.5 g ÷ 1.045 g/ml = 3.35 ml of vitamin premix used.)

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