Specifications and methods of analysis of raw materials for recombining milk are assembled in this chapter.
5.1.1 Scope
This method specifies a routine method for the determination of the titratable acidity of all types of dried milk.
5.1.2 Definition
The titratable acidity of dried milk is defined as the number of millilitres of a 0.1 N sodium hydroxide solution required to titrate a quantity of the reconstituted sample corresponding to 10 g of fat free dry milk solids to the colour change point of phenolphthalein according to the procedure prescribed.
5.1.3 Principle of method
The test sample is reconstituted in water and titrated with a 0.1 N sodium hydroxide solution using phenolphthalein as indicator and cobaltous sulphate as a reference colour solution.
The amount of sodium hydroxide solution required is determined by the natural buffering substances of the milk constituents, by developed or added acid or alkaline substances.
5.1.4 Reagents
All reagents should be of analytical reagent quality.
Solution of sodium hydroxide standardized to 0.1 N ± 0.0002.
Distilled or deionized water, free from carbon dioxide by boiling for 10 min. before use.
Phenolphthalein indicator solution. Dissolve 2 g phenolphthalein in 70% (v/v) ethyl alcohol and make up to 100 ml. The ethyl alcohol should be neutralized if required.
Reference colour solution. Dissolve 3 g cobaltous sulphate (CoSo4. 7H2O) in distilled water and make up to 100 ml.
5.1.5 Apparatus and glassware
Balance, 0.01 g or better sensitivity.
Burette, graduated to 0.1 ml and with an accuracy of 0.05 ml.
Pipettes of 2 ml capacity.
Graduated cylinders of 50 ml capacity.
Conical flasks with ground glass stoppers, 100 ml or 150 ml capacity.
5.1.6 Procedure
Preparation of the sample
Transfer the sample to a clean, dry container (provided with an air-tight lid) of a capacity about twice the volume of the sample. Close the container immediately and thoroughly mix the contents by repeatedly shaking and inverting the container. During these operations, exposure of the sample to the atmosphere should be avoided as far as possible, to minimize absorption of water.
Determination
Weight 
g ± 0.01 g quantities of the sample into each of two conical flasks (5.5).
a = the fat free dry milk solids content of the sample.
Add 50 ml of water (4.2) of about 20°C to each of the conical flasks.
Reconstitute thoroughly by vigorous agitation and allow to stand for about 20 min.
Add to one of the conical flasks 2 ml of the reference colour solution to obtain a colour standard, mix by slight swirling.
If a series of determinations of similar powders is to be carried out, this colour standard may be used throughout. The colour standard, however, should not be used for more than 2 h.
Add 2 ml of the phenolphthalein indicator solution to the second conical flask, mix slight swirling.
Titrate the content of the conical flask by adding the sodium hydroxide solution, while swirling until a faint pink colour similar to the colour standard persists for about 5 sec. The titration time should not exceed 45 sec. Record the number of millilitres of sodium hydroxide solution used to the nearest 0.05 ml.
5.1.7 Calculation
Titratable acidity = 2 × V
where
V= the number of millilitres of 0.1 N sodium hydroxide solution used under last para.
of 5.1.6 above.
Results should be reported to one decimal place.
5.1.8 Repeatability of results
The difference between results of duplicate determination (results obtained simultaneously or in rapid succession by the same analyst) should not exceed 0.4.
5.1.9 Check
Check from time to time if the titration has been carried out in such a way that this method gives on the average the same results as the reference method.
5.1.10 Test report
The test report shall show the method used and the result obtained. It shall also mention any operating conditions not specified in this standard, or regarded as optional, as well as any circumstances that may have influenced the result. The test report shall include all details required for the complete identification of the sample.
5.2.1 Scope
This standard specifies a reference method for the determination of water soluble and insoluble volatile fatty acid values (Reichert and Polenske values) of milk fat.
5.2.2 Definitions
The soluble volatile fatty acid value (Reichert or Reichert-Meissl-Wollny- value) is the number of millilitres of aqueous 0.1 N alkali solution required to neutralize the water soluble volatile fatty acids obtained from 5 grammes of fat under the specific conditions of the method.
The insoluble volatile fatty acid value (Polenske value) is the number of millilitres of acqueous 0.1 N alkali solution required to neutralize the water insoluble volatile fatty acids obtained from 5 grammes of fat under the specific conditions of the method.
5.2.3 Principle
After saponification of the fat with sodium hydroxide solution in glycerol, the soap solution is diluted with water and acidified with sulphuric acid. The volatile fatty acids are distilled and the insoluble fatty acids are separated from the soluble acids by filtration. The aqueous solution of the soluble acids and the ethanolic solution of the insoluble acids are then titrated separately with a standardized alkali solution.
The method is empirical for it determines only a part of these acids. Consequently, the specifications for procedure and apparatus must be followed rigorously in order to obtain accurate and reproducible results.
5.2.4 Reagents
Glycerol (d = 1.26; 98 % w/w);
Aqueous sodium hydroxide solution (44 % w/w), stored in a bottle protected from carbon dioxide. Use the clear portion free from carbonate deposit.
Distilled water freed from carbon dioxide by boiling for 15 minutes.
Sulphuric acid solution (1 N).
Aqueous sodium or potassium hydroxide solution (0.1 N) accurately standardized.
Phenolphthalein indicator solution (1 % in 95–96 % ethanol).
Ethanol (95–96 % v/v). neutral to phenolphthalein.
All reagents shall be of analytical grade. Water used should be distilled water or water of at least equal purity.
5.2.5 Apparatus and auxiliaries
(Ordinary laboratory tools are not mentioned).
Flat-bottomed flask of borosilicate glass and of 300 ml capacity.
Connector still-head.
Condenser.
Receiver, consisting of a measuring flask with circular graduation marks at 100 and 110 ml.
Sheet of asbestos, diameter 120 mm, thickness 6 mm, with a central circular hole 40 to 50 mm in diameter, to support the flask during heating.
Pumice stone pieces, passing a 2 mm circular mesh sieve and retained on a 1.4 mm circular mesh sieve according to draft ISO Recommendation No. 805.
Note: Rubber, neoprene or silicone stoppers or standard ground glass joints 24/40 may be used for connections.
5.2.6 Sampling
See International Standard FIL-IDF 2: “Standard Methods for Sampling Milk and Milk Products” (latest edition).
5.2.7 Procedure
Preparation of the sample
See para. 7.1 of International Standard FIL-IDF 32: 1965 (Detection of Vegetable Fat in Milk Fat by the phytosteryl acetate test).
Determination of soluble volatile fatty acid value
Weigh 5.00 ± 0.01 g of the fat into the flask. Add 20 g (16 ml) of glycerol and 2 ml of the sodium hydroxide solution (44 %).
Note: For supplying the sodium hydroxide solution, use a burette protected from the entry of carbon dioxide and clean the burette jet by rejecting the first few drops from the tap.
Heat the flask over a naked flame, avoiding overheating and shaking continuously until the liquid no longer foams and becomes clear.
Allow the flask to cool to about 90°C, add 90 ml of recently boiled distilled water of about the same temperature and mix. The liquid should remain clear. Add 0.6 to 0.7 g of the pumice and then 50 ml sulphuric acid solution (1 N).
Connect the flask immediately to the distillation apparatus and warm it gently until the free fatty acids form a clear surface layer.
Start heating and regulate the flame so as to collect in the measuring flask 110 ml of distillate in 19–21 min., taking the moment when the first drop forms in the condenser as the beginning of the distillation period. Regulate the water flowing in the condenser so as to maintain the temperature of the water leaving the condenser at 20 ± 1°C.
Note: If the temperature of the cooling water exceeds 20°C as in tropical and sub-tropical areas, and if no special arrangements can be made, the measuring flask should stay in the waterbath (see third para. of this Note) at 20± 1°C for about 1 hour.
When exactly 110 ml of distillate have been collected, remove the burner immediately and substitute a small beaker for the measuring flask.
Mix the contents of the measuring flask by gentle shaking and immerse the flask in a waterbath at 20 ± 1°C for 10 to 15 minutes, the 110 ml mark on the flask being 1 cm below the level of the water in the waterbath and the flask being turned from time to time.
Stopper the flask and mix by inverting it 4 to 5 times without shaking.
Filter the 110 ml of distillate through a dry medium speed filter paper (diameter 80–90 mm) which fits snugly into the funnel. The filtrate should be clear.
Note: The filter should be of such a size that 15 ml poured into it will fill it completely.
Pipette 100 ml of the filtrate into a conical flask of 300 ml, add 0.5 ml of phenolphthalein indicator solution and titrate with the standardized aqueous alkali solution (0.1 N) to a pink colour persistent for 1/2 to 1 minute.
Blank test
Conduct a blank test without fat and instead of saponifying over a naked flame, heat over a boiling waterbath for 15 minutes.
Note: Not more than 0.5 ml of the standardized alkali solution should be required for the titration. Otherwise, new reagent solutions should be prepared.
Determination of insoluble volatile fatty acid value
Rinse the filter with three successive 15 ml portions of distilled water at a temperature of 20 ± 1°C, each having previously passed through the condenser, the small beaker and the measuring flask.
Place the funnel and filter in the neck of a dry clean conical flask of 200 ml capacity.
Dissolve the insoluble fatty acids by repeating the washing procedure using now 15 ml portions of ethanol (95–96 %).
Titrate the combined ethanolic washings with the standardized aqueous alkali solution (0.1 N), using 0.5 ml of phenolphthalein indicator solution, to a pink colour persistent for 1/2 to 1 min.
5.2.8 Calculation
Soluble volatile fatty acid value (Reichert value)
Reichert value = 11.t. (v1 - b)
where
v1 = number of millilitres standardized alkali solution (0.1 N) required for the
sample in 5.2.7
b = number of millilitres standardized alkali solution (0.1 N) required for the
blank test in 5.2.7
t = exact normality of the standardized alkali solution (0.1 N).
Report the result rounded to the first decimal place.
Insoluble volatile fatty acid value (Polenske value)
Polenske value = 10.t.v2 where v2 = number of ml standardized alkali solution (0.1 N) required for the sample in 5.2.7 t = exact normality of the standardized alkali solution (0.1 N).
Report the result rounded to the first decimal place.
5.2.9 Repeatability of results
The difference between results of duplicate determinations (results obtained simultaneously or in rapid succession by the same analyst) should not exeed 0.5 for the Reichert value and 0.3 for the Polenske value.
5.3.1 Scope and field of application
Scope
This standard describes a method for the determination of the peroxide value of anhydrous milk fat1
Field of application
The method is suitable for anhydrous milk fat having a peroxide value which does not exceed 1.0.
5.3.2 Definition
The peroxide value means the number of milligram-equivalents of oxygen per kilogram of anhydrous milk fat, determined by the procedure described.
5.3.3 Principle of the method
Solution of a weighed amount of the sample in a mixture of chloroform and methanol and addition of some iron (II) chloride and ammonium thiocyanate. After a fixed reaction time, photometric determination of the amount of red iron (III) complex.
5.3.4 Reagents
All reagents shall be of analytical reagent quality. Water used shall be distilled water or water of at least equivalent purity.
Mixture of 70 volume parts of chloroform (trichloromethane) and 30 volume parts of anhydrous methanol.
Iron (II) chloride solution
This solution shall be prepared in indirected, dimmed light. Dissolve approximately 0.4 g barium chloride (BaCl2.2H2O) in about 50 ml of water.
Dissolve approximately 0.5 g iron (II) sulphate (FeSO4.7H2O) in about 50 ml of water.
Slowly pour the barium chloride solution, with constant stirring, into the iron (II) sulphate solution and add about 2 ml of approximately 10 N hydrochloric acid.
Allow the precipitate of barium sulphate to settle or centrifuge the mixture until the upper liquid layer is clear. Decant the clear solution into a brown bottle. Do not store the solution for more than 1 week.
Note: The iron (II) chloride solution can also be prepared by dissolving approx. 0.35 g iron (II) chloride FeC12.4H2O in about 100 ml of water and adding 2 ml of approx. 10 N hydrochloric acid.
Ammonium thiocyanate solution
Dissolve approximately 30 g ammonium thiocyanate (NH4SCN) in water and dilute to 100 ml. If the solution is not colourless, remove the colour by extracting the solution. several times with small amounts (e.g. 5 ml portions) of iso-amyl alcohol (3-methylbutanol-l).
Standard solution of iron (III) chloride (10 microgrammes of Fe per ml)
Dissolve 0.500 g iron powder in about 50 ml of 10 N hydrochloric acid and add 1 to 2 ml of about 30 % (m/m) hydrogen peroxide solution.
Remove the excess of hydrogen peroxide by boiling for 5 minutes. Cool to room temperature and dilute with water to 500 ml. Transfer, by means of a pipette 1 ml of this solution to a measuring flask and dilute with the mixture of chloroform and methanol (4.1) to 100 ml.
Hydrochloric acid solution, approximately O.2 N
Dilute 2 ml of about 10 N hydrochloric acid with water to 100 ml.
5.3.5 Apparatus
Analytical balance, sensitivity 1 mg.
Burettes of 10 ml capacity, with scale divisions at each 0.02 ml.
Pipettes with scale, of 1 ml capacity, provided with graduation marks at each 0.05 ml.
Photometer, suitable for measuring at a wavelength of 500 mm, with appropriate cuvettes of at least 20 ml capacity and a light-path of at least 1.5 cm.
5.3.6 Sampling
See FIL-IDF Standard 50: “Standard methods for sampling milk and milk products”.
5.3.7 Procedure
Precautions
In order to eliminate lipid oxidation, the following precautions shall be followed:
Exposure of the sample of anhydrous milk fat to light shall be avoided.
Take care that the procedure described in the first four paras. under “Determination” below, with inclusion of a reaction time of 5 minutes, is completed within 10 minutes.
Carry out the test in indirect light, subdued as much as is practicable.
Determination
Weigh in a photometer cuvette, about 0.3 g of anhydrous milk fat to the nearest 1 mg. Add from a burette (5.3.5) 9.6 ml of the mixture of chloroform and methanol (5.3.4) and dissolve the fat in this mixture.
Note: for batchwise determination, it may be advantageous to carry out the analysis in test tubes with ground glass stoppers.
Add from a graduated pipette (5.3.5) 0.05 ml of the ammonium thiocyanate solution and mix.
Measure the extinction (Efat blank) at 500 mm against the mixture of chloroform and methanol.
Add from agraduated pipette (5.3.5) 0.05 ml iron (II) chloride solution and mix. Wait 5 minutes. Then measure the extinction (Esample) against the mixture of chloroform and methanol.
Carry out a blank test according to first, second and fourth (Note excluded) paras. above, without fat (extinction observed = Ereagent blank).
Reference curve
Transfer from a burette to four cuvettes 0.5 ml, 1 ml, 1.5 ml and 2 ml respectively of the standard iron solution (5.3.4) in order to obtain a series with 5, 10, 15 and 20μg of iron (III) ion. Add from burettes conforming to 5.3.5 to these four cuvettes 9.4 ml, 8.9 ml. 8.4 ml and 7.9 ml respectively of the mixture of chloroform and methanol. Add from a graduated pipette (5.3.5) to each of these four cuvettes 0.05 ml of ammonium thiocyanate solution and from another graduated pipette 0.05 ml of about 0.2 N hydrochloric acid solution and mix.
Wait for 5 minutes. Then measure the extinctions against the mixture of chloroform and methanol.
Plot the extinctions of the members of the series against the added amounts of iron (III) ion, expressed as μ g Fe(III).
Construct the best fitting straight line through the points.
5.3.8 Expression of results
Method of calculation
Esample = extinction obtained under 5.3.7 on examination of the sample.
Efat blank = extinction obtained under 5.3.7.
Ereagent blank = extinction obtained under 5.3.7.
Calculate from the difference of extinction:
Esample - (Ereagent blank + Efat blank) by means of the reference curve, or by means of the factor calculated from the reference curve, the content (a) of iron (III) in μ g.
The peroxide value of the fat, expressed as milligramme equivalents per kilogramme is
where
a = the content of iron (III) in μ g found
m = mass of test portion in grammes.
Express the result to the nearest 0.01 unit of peroxide value.
Repeatability
The difference between the results of two determinations, carried out simultaneously or in rapid succession by the same analyst, using the same apparatus, should not exceed 0.05 unit of peroxide value.
5.3.9 Test report
The test report shall show the method used and the result obtained. It shall also mention any operating conditions not specified in this standard, or regarded as optional, as well as any circumstances that may have influenced the result. The test report shall include all details required for the complete identification of the sample.
Explanatory note: This standard is largely derived from a Nevetherlands draft standard. Contrary to the Australian standard, the extinction is measured at a wavelength of 500 nm (instead of at 505 nm) where the absorption of the red iron (III) complex appeared to be maximum when using a spectrophotometer with calibrated wavelength scale.
5.4.1 Definition of the total Nitrogen content
The total nitrogen content of milk means the nitrogen content expressed in percent by weight obtained by the Kjeldahl method.
5.4.2 Scope
The standard method is applicable only to normal fresh milk. If the protein content of the milk is calculated on the basis of the total nitrogen content, the factor employed must be given.
5.4.3 Principle of method
A weighed quantity of milk is digested with sulphuric acid in the presence of mercuric oxide as a catalyst in order to convert the nitrogen of the organic compounds into ammoniacal nitrogen. The ammonia is released by the addition of sodium hydroxide, distilled and absorbed in boric acid. The ammonia is then titrated.
5.4.4 Reagents
Potassium suphate.
Mercuric oxide, red.
Sulphuric acid, concentrated (density 1.84 at 20°C).
Sodium hydroxide solution, 500 g sodium hydroxide and 12 g sodium sulphide (Na2S, 9H2O) dissolved in 1 000 ml of distilled water.
Boric acid solution, 40 g boric acid dissolved in 1 000 ml distilled water.
Hydrochloric acid, 0.1 N.
Indicator, 2 g methyl red and 1 g methylene blue dissolved in 1 000 ml ethanol (96 % v/v).
Sodium tetraborate for the standardization of the hydrochloric acid.
All chemicals and solutions used must be free from nitrogenous substances.
5.4.5 Apparatus and auxiliary agents
Analytical balance, sensitivity 1 mg.
Digestion apparatus to hold the Kjeldahl flask in an inclined position and with a heating device which will not heat the part of the flask above the surface of the liquid contents.
Kjeldahl flask of 500 ml capacity.
Liebig condenser with straight inner tube.
An outlet tube with safety bulb connected to the lower end of the condenser with a rubber tube to give glass to glass contact.
Splash head connected to the Kjeldahl flask and to the Liebig condenser by soft rubber stoppers.
Conical flask of 500 ml capacity.
Graduated cylinder, 25, 50, 100 and 150 ml.
Burette of 50 ml capacity in 1/10 ml.
Substances to facilitate boiling.
For digestion: Pieces of hard porcelain or glass beads.
For distillation: Freshly calcined pieces of pumice.
5.4.6 Sampling
See International Standard FIL-IDF 2: 1958: “Methods of sampling milk and milk products”.
5.4.7 Procedure
Preparation of the sample
Prior to analysis bring the sample to 20 ± 2°C and mix carefully. If the fat cannot be evenly dispersed, heat the sample slowly to 40°C, mix gently and cool to 20± 2°C.
Determination
Place successively in the Kjeldahl flask a few glass beads or small pieces of porcelain, about 10 g potassium sulphate, 0.5 g mercuric oxide and about 5 g of milk weighed to an accuracy of 1 mg.
Add 20 ml of sulphuric acid and mix the contents of the flask.
Heat the Kjeldahl flask carefully on the digestion apparatus until the foaming stops and the contents have become liquid.
Continue the digestion with more vigorous heating until the contents of the Kjeldahl flask are completely clear and colourless. During heating mix the contents from time to time.
Allow the liquid to boil vigorously for 1 1/2 hours after it has become clear. Avoid local overheating.
Allow the contents of the flask to cool to room temperature, add about 150 ml distilled water and a few pieces of pumice, mix and allow to cool again.
Measure 50 ml of the boric acid solution into the conical flask, add 4 drops of the indicator and mix.
Place the conical flask under the condenser so that the tip of the outlet tube is below the surface of the boric acid solution. Measure 80 ml of the sodium hydroxide solution into the Kjeldahl flask, holding the flask in an inclined position so that the hydroxide solution runs down the side and does not mix with the contents.
Connect the Kjeldahl flask with the condenser by means of the splash head. Mix the contents of the Kjeldahl flask by swirling. Heat to boiling. Avoid frothing. Continue the distillation until the contents of the flask start bumping. Regulate the heating so that the distillation takes at least 20 minutes. Cool the distillate well and do not let the solution of boric acid become warm.
Shortly before the end of the distillation, lower the conical flask so that the tip of the outlet tube is no longer immersed in the boric acid solution.
Stop heating and remove the outlet tube, rinsing its outer and inner walls with a little distilled water. Titrate the distillate with 0.1 N hydrochloric acid.
Blank test
Carry out a blank test as described under “Determination” above, using 5 ml of distilled water in place of milk.
5.4.8 Expression of results
Method of calculation
Calculate the total nitrogen content by means of the formula:
Total nitrogen content % = 
N = normality of the hydrochloric acid.
V1 = number of ml of hydrochloric acid used in the determination
V0= number of ml of hydrochloric acid used in the blank test
P = weight (in grammes) of milk taken for analysis.
Accuracy of the determination
The maximum deviation between duplicate determinations should not exceed 0.005 % of nitrogen.
5.5.1 Definition of the fat content
The fat content means the total content of fat and fatty substances, expressed in percent by weight, that is obtained when determining the fat content of normal dried milk by the Röse-Gottlieb method.
5.5.2 Analysis
Apparatus and auxiliary agents
Analytical balance, sensitivity 0.1 mg.
Drying oven maintaining constant temperature up to 110°C or vacuum drying oven.
Erlenmeyer or flat-bottomed flasks holding 150 to 250 ml, with ground glass identification marks.
Substance to facilitate boiling, free of fat, e.g. ground pumice.
Suitable extraction tubes or flasks, with airtight corks or ground glass stoppers.
Reagents
Ammonia solution 25% (density 0.91 at 15°C), clear, colourless.
Ethyl alcohol, 96 volume % (± 1 vol. %). Instead of pure alcohol, ethyl alcohol leaving no residue and denaturated with methyl alcohol or with light petroleum, may be used.
Ethyl ether, boiling range 34 to 35°C, peroxide-free.
Light petroleum, boiling range 40 to 60°C.
The reagents used shall leave no residue after evaporation.
In order to control the reagents, a blank test corresponding exactly to the procedure, yet without dried milk, is to be carried out. A small quantity of pure fat is introduced into the receiving flask before it is dried and weighed. The blank estimation must be taken into account in the final calculation of the analysis, but the value should not exceed an almost negligible quantity.
Preparation of the sample
The absorption of moisture must be carefully avoided during the preparation for analysis. Mix the dried milk by transferring the sample in a dry flask of twice the volume, with stopper. Mix the contents carefully by shaking and turning upside down repeatedly. Open quickly and close immediately.
Procedure
Weigh exactly about 1 g of dried whole milk, resp. 1.5 g of dried skimmed milk, into the extraction apparatus.
Add 10 ml of water, shake and, if necessary, gently heat in a water bath, until the milk powder is completely dispersed.
Add 1.5 ml of ammonia solution, heat in a water bath at 60 to 70°C during 15 minutes, and shake occasionally.
Cool, add 10 ml of ethyl alcohol, and mix the contents.
Add 25 ml of ethyl ether, close the extraction apparatus, then mix the contents by shaking and inverting repeatedly for one minute.
Add 25 ml of light petroleum, close the extraction apparatus and mix the contents by shaking and turning upside down repeatedly.
Let the extraction apparatus stand for at least two hours or centrifuge (for not less than 5 minutes at 500 to 600 r.p.m.) until the light petroleum-ether layer is perfectly clear and has entirely separated from the aqueous layer.
Transfer the light petroleum-ether layer as completely as possible by decanting or by means of a pressure siphon (taking care, however, that no part of the aqueous phase is carried over) into an Erlenmeyer or flat-bottomed flask containing a substance which facilitates boiling and which has already been dried and weighed. Then rinse the stopper of the extraction apparatus and the pressure siphon with a few millilitres of light petroleum.
Repeat the extraction a second and third time, using each time 25 ml of ethyl ether and 25 ml of petroleum spirit, as indicated in the fifth and sixth paras. above, and transferring each time the upper layer into the same flask after clarification by centrifuging or allowing to stand.
Carefully distil the solvents from the flask.
After evaporation of the solvents, dry the fat for one hour either in a vacuum drying oven at 70 to 75°C (pressure less than 50 mm Hg) or in a drying oven under normal pressure at 102 to 105°C. The flask is dried in a lying position.
Let the flask cool and weigh it after it has reached room temperature.
Continue the drying process to constant weight (vacuum drying) or to a slight increase of weight (drying under normal pressure). In the latter case, take the last value found before the increase of weight occurs, as a basis for the calculation.
If considered necessary, the fat can be taken up again with light petroleum in order to control the result of the analysis.
Accuracy of the method
Fat % ± 0.10 %.
5.6.1 Scope
This reference method specifies the determination of the acid value of butterfat.
5.6.2 Definition
The acid value of butterfat is the number of milligrammes of potassium hydroxide required to neutralize one gramme of the fat.
5.6.3 Principle of method
The fat, after separation by melting the butter, is dissolved in a mixture of ethanol and diethyl ether and titrated with dilute alkali solution.
5.6.4 Reagents
Reagents should be of analytical reagent quality.
Alcoholic potassium hydroxide solution, approx. 0.1 N, standardized. Use absolute methanol or ethanol.
Mixture of equal volume of ethanol 95–96% (v/v) - or of ethanol denatured with methanol - and diethyl ether, neutral to the indicator used in the following para.
Neutral solution of phenolphthalein 1 % (m/v) in ethanol 95–96% (v/v), or in ethanol denatured with methanol.
5.6.5 Apparatus
Analytical balance.
Conical flasks of 300 ml capacity.
Calibrated burette, graduated to 0.1 ml.
5.6.6 Sampling
See methods of sampling milk and milk products in latest edition of FIL-IDF Standard 2.
5.6.7 Procedure
Preparation of the sample
To separate the fat, melt the sample and let it stand at 50–60°C for 2–3 hours, decant and filter through a dry paper filter. Refilter if not clear. Use the well-mixed, melted and clarified fat.
Determination
Weigh into the conical flask 5–10 g of the fat (prepared as above in “Preparation of the sample”) to the nearest milligramme.
Add 50–100 ml of the ethanol/ether mixture (5.6.4) and dissolve the fat.
Add 0.1 ml of phenolphthalein solution (5.6.4).
Titrate with the alkali solution to a pale pink colour persistent for at least 10 seconds.
5.6.8 Expression of results
Calculation
Acid value = 
where:
v = number of ml of alkali solution used in fourth para. under “Determination” above
t = normality of the alkali solution
a = mass, in grammes, of test portion.
Repeatability of results
The difference between results of duplicate determinations (results obtained simultaneously or in rapid succession by the same analyst) should not exceed 0.1 mg potassium hydroxide for one gramme of fat.
5.7.1 Apparatus and glassware
Analytical balance, sensitivity 0.1 mg.
Erlenmeyer flask with ground glass stopper, capacity 300–500 ml.
Burettes, graduated to 0.1 ml, inspected and approved.
5.7.2 Reagents
Wijs' Reagent.
Carbon tetrachloride (CCl4), inert to Wijs' solution.
Potassium iodide solution, 10%, free from iodine and iodates.
Sodium thiosulphate solution, 0.1 N.
Starch solution
Preparation of the Wijs' reagent and of the starch solution.
Wijs' reagent: Dissolve approximately 9 g of iodine trichloride in 1 000 ml of a mixture of 700 ml concentrated acetic acid (99–100%) and 300 ml of carbon tetrachloride, both free from oxidizable matter.
Determine the halogen concentration in the following way: run 5 ml of the solution from a burette into a flask, add 5 ml of the 10% potassium iodide solution and 30 ml of water, and titrate with 0.1 N sodium thiosulphate using a starch solution as indicator. Add the starch solution shortly before the end of the titration.
After the determination of the halogen content of the iodine trichloride solution add 10 g of iodine powder and swirl until enough of the iodine has dissolved that the halogen content, determined as above, has increased to considerably more than 1.5 times the original value. Filter or decant the clear solution and dilute it with a mixture of acetic acid and carbon tetrachloride, so that 5 ml of the solution are equivalent to 10 ml of the 0.1 N sodium thiosulphate solution. Keep the solution in the dark in a tightly closed stoppered bottle of brown glass.
Starch solution: mix 5 g of soluble starch and 10 mg of mercuric iodide in 30 ml water, add this mixture to 1 000 ml of boiling water and leave boiling for 3 minutes.
5.7.3 Preparation of the sample
To obtain a sample of the butterfat, melt the butter at 50 to 60°C, leave standing in the dark for some time, decant and filter through a dry filter. For the determination of the iodine value use the melted, clear, filtered and well-mixed butterfat.
5.7.4 Procedure
Weigh accurately 0.4 to 0.45 g of the clear butterfat in a clean dried Erlenmeyer flask.
Dissolve the fat in 15 ml carbon tetrachloride and add by means of a burette exactly 25 ml of the Wijs' reagent.
Close the flask with its stopper, mix carefully and leave it standing for 1 hour in the dark.
Add 20 ml potassium iodide solution and approximately 150 ml of distilled water, and mix.
Titrate with 0.1 N sodium thiosulphate solution (use as indicator 2 ml of starch solution), swirling the liquid constantly. Add the starch solution shortly before the end of the titration.
Carry out a blank test, using the same quantities of the reagents.
Calculate the iodine value by means of the following formula:
Iodine value = 
where:
a = number of ml of 0.1 N sodium thiosulphate used in the blank test.
b = number of ml of 0.1 N sodium thiosulphate used in the titration with the butter-fat present.
p = weight of butterfat taken for the analysis.
5.7.5 Accuracy of the method
The results of duplicate determinations should not differ by more than 0.4.
5.8.1 Definition of acidity
The acidity of butterfat is expressed in “degree of acidity”. The “degree of acidity” of butterfat is the number of millilitres of 1-normal alkali required to neutralize the free fatty acids in 100 g of butterfat prepared as under 5.8.2, below, “Preparation of the sample”.
5.8.2 Analysis
Apparatus
Analytical balance, sensitivity 0.1 mg.
Erlenmeyer flasks of 300 ml capacity.
Burette calibrated to 0.1 ml.
Reagents
Neutralized mixture of alcohol and ether (equal parts of ethyl alcohol 95% and ethyl ether, neutralized to phenolphthalein).
0.1 normal solution of NaOH or KOH.
Alcoholic solution of phenolphthalein, 1 %.
Preparation of the sample
To extract the butterfat, melt the butter at 50 to 60°C, let it stand some time in the dark, decant and filter through a dry filter. For the determination of the acidity, use the well-mixed, melted and clarified butterfat.
Procedure
Weigh into the Erlenmeyer flask 5 to 10 g to the nearest mg of the butterfat prepared according to “Preparation of the sample” above.
Add 50 ml or more of the ether-alcohol mixture to dissolve the butterfat.
Add 1 ml of phenolphthalein solution.
Titrate with 0.1 normal alkali to a pale pink colour.
Calculate the degree of acidity from the following formula:
Degree of acidity = 
p = the weight of butterfat in g.
n = the quantity of alkali used, expressed as ml 1-normal solution.
Acuracy of the method
The maximum deviation between duplicate determinations should not exceed 0.2 degree of acidity.
5.9.1 Scope and field of application
This standard specifies a reference method for the determination of the titratable acidity of all types of dried milk.
5.9.2 Reference
FIL-IDF Standard 50: 1969 - Standard methods for sampling milk and milk products.
FIL-IDF Standard 9A: 1969 - Determination of the fat content of dried milk (Reference method).
FIL-IDF Standard 26: 1964 - Determination of the water content of dried milk.
5.9.3 Definition
Titratable acidity of dried milk: The number of millilitres of a 0.1 N sodium hydroxide solution required to titrate a quantity of the reconstituted product corresponding to 10 g of solids-non-fat to the pH of 8.3.
5.9.4 Principle
Reconstitution of the product in water and titration with a 0.1 N sodium hydroxide solution to the pH of 8.3.
The amount of sodium hydroxide solution required is a function of the amount of natural buffering substances present in the product, and of developed or added acid or alkaline substances.
5.9.5 Reagents
All reagents shall be of analytical quality. Water shall be distilled or deionized water, free from carbon dioxide by boiling for 10 min before use.
Sodium hydroxide, 0.1 ± 0.0002 N standard volumetric solution.
Protect this solution against penetration of carbon dioxide.
Nitrogen.
5.9.6 Apparatus and glassware
Balance, 0.01 g or better sensitivity.
pH meter, with a glass electrode and a suitable reference electrode, calibrated using buffers with pH of about 6 and 9, known to within 0.01 pH unit.
Magnetic stirrer.
Burette, graduated in 0.1 ml and with an accuracy of 0.05 ml.
Measuring cylinder of 50 ml capacity.
Conical flask, 100 ml or 150 ml capacity, with ground glass stopper.
The neck must accommodate the two electrodes, the burette tip and the nitrogen line.
5.9.7 Sampling
See FIL-IDF Standard 50: 1969 - Standard methods for sampling milk and milk products.
5.9.8 Procudure
Preparation of the test sample
Transfer the sample to a clean, dry container (provided with an air-tight lid) of a capacity about twice the volume of the sample. Close the container immediately and thoroughly mix the contents by repeatedly shaking and inverting the container. During these operations, exposure of the sample to the atmosphere should be avoided as far as possible, to minimize absorption of water.
Determination
Weigh 
± 0.01 g of the test sample (see above “Preparation of the test sample”)
into the conical flask (see “Apparatus and glassware” above), a being the solids-non-fat\
content of the sample, expressed as a percentage.
Note: The solids-non-fat content of the sample may be calculated by subtracting the fat content (determined in accordance with FIL-IDF Standard 9A) and the moisture content (determined in accordance with FIL-IDF Standard 26) from 100.
Reconstitute the test portion (see above) with 50 ml of water at about 20°C, agitating vigorously, and allow to stand for about 20 min.
Titrate the contents of the conical flask by adding the sodium hydroxide solution (see 5.9.5) from the burette (5.9.6) until the pH has reached 8.3, measured with the pH meter (5.9.6); during the titration, the solution should be stirred using the magnetic stirrer (5.9.6), and absorption of carbon dioxide from the air should be avoided by flushing the conical flask with nitrogen. The titration should be completed within 1 min.
Record the volume, in millilitres, of sodium hydroxide solution used, to the nearest 0.05 ml.
5.9.9 Expression of results
Method of calculation and formula
The titratable acidity is equal to 2 × V
where V is the volume, in millilitres, of the sodium hydroxide solution used for the titration (5.9.8).
Express the result to one decimal place.
Repeatability
The difference between the results of two determinations carried out simultanously or in rapid succession by the same analyst shall not exceed 0.4.
5.9.10 Test report
The test report shall show the method used and the result obtained. It shall also mention any operating conditions not specified in this standard, or regarded as optional, as well as any circumstances that may have influenced the result. The test report shall include all details required for the complete identification of the sample.
5.10.1 Scope
This reference method specifies the determination of the fat content of whole milk powder, partly skimmed milk powder and skimmed milk powder.
5.10.2 Definition
The fat content of milk powder is defined as the percentage by mass of substance as determined by the procedure described.
5.10.3 Principle of method
The fat content is gravimetrically determined by extraction of the fat from an ammoniacal alcoholic solution of milk powder with diethyl ether and light petroleum, evaporation of the solvents and weighing of the residues, according to the principle of Röse-Gottlieb.
5.10.4 Reagents
All reagents should be of analytical reagent quality and leave no residue greater than that permitted for the blank test. If necessary, reagents may be redistilled in the presence of about 1 g of butterfat for 100 ml of solvent. Water used should be distilled water or water of at least equal purity.
Ammonia solution, approx. 25% (m/v) NH3 (ρ 20°C approx. 0.91 g/ml), or a stronger solution of known concentration.
Ethanol, 96 ± 2 % (v/v) or, if not available, ethanol denatured with methanol, ethyl methyl ketone, benzene or light petroleum.
Diethyl ether, peroxide-free.
Note 1: to test for peroxides, add to 10 ml of the ether in a small glass stoppered cylinder, previously rinsed with the ether, 1 ml freshly prepared 10 % potassium iodide solution. Shake and let stand for 1 minute. No yellow colour should be observed in either layer.
Note 2: diethyl ether may be maintained free from peroxides by adding wet zinc foil that has been completely immersed in dilute acidified copper sulphate solution for 1 minute and subsequently washed with water. Use per litre approximately 80 cm2 zinc foil; cut in strips long enough to reach at least halfway up the container.
Light petroleum (petroleum ether) with any boiling range between 30 and 60°C.
Mixed solvent, prepared shortly before use by mixing equal volumes of diethyl ether (see above) and light petroleum (see above) (where mixed solvent is specified, the diethyl ether or the light petroleum may be used instead).
5.10.5 Apparatus
Analytical balance.
Suitable extraction tubes or flasks, provided with ground glass stoppers, bark corks, or other closures unaffected by solvents used. Treat good quality bark corks by extracting successively with diethyl ether and light petroleum. Then keep for at least 20 minutes in water at 60°C or above and cool in the water so that they are saturated when used.
Thin-walled, flat-bottomed flasks of 150–250 ml capacity.
Drying oven, well ventilated and thermostatically controlled (adjusted to operate at 102 ± 2°C) or vacuum drying oven (temperature 70–75°C, pressure less than 50 mm Hg).
Material to facilitate boiling, fat-free, non-porous, non-friable in use, e.g. glass beads or pieces of silicon carbide (the use of this material is optional: see “Determination” below).
Waterbath at 60–70°C.
5.10.6 Sampling
See methods of sampling milk and milk products in latest edition of FIL-IDF Standard 2.
5.10.7 Procedure
Preparation of the sample
Transfer the milk powder to a clean, dry container (provided with an air-tight lid) of a capacity about twice the volume of the powder. Close the container immediately and thoroughly mix the milk powder by repeatedly shaking and inverting the container. During the preparation of the sample, exposure of the milk powder to the atmosphere should be avoided as far as possible to minimize absorption of moisture.
Blank test
At the same time as the determination of the fat content of the sample, perform a blank determination on 10 ml of distilled water using the same type of extraction apparatus the same reagents in the same amounts and the same procedure as described hereafter under “Determination”, excluding second para. If blank determination exceeds 0.5 mg, the reagents should be checked and the impure reagent or reagents should be purified or replaced.
Determination
Dry the flask (5.10.5) (if desired, with some material (5.10.5) to promote gentle boiling during the subsequent removal of the solvents) in the oven for 0.5 to 1 hour. Allow the flask to cool to the temperature of the balance room and weigh the cooled flask to the nearest 0.1 mg.
Weigh to the nearest 1 mg directly in, or by difference into, the extraction apparatus (5.10.5) about 1 g of whole milk powder or about 1.5 g of partly skimmed or skimmed milk powder. Add 10 ml water and shake until the milk powder is completely dispersed.
Add 1.5 ml ammonia (25%) or an equivalent volume of a stronger solution and heat in a waterbath for 15 minutes at 60–70°C, shaking occasionally. Cool, for example, in running water.
Add 10 ml ethanol and mix the liquids gently but thoroughly in the unclosed apparatus.
Add 25 ml diethyl ether, close the apparatus and shake vigorously and invert repeatedly for 1 minute. Cool, if necessary, in running water.
Remove the stopper carefully and add 25 ml light petroleum using the first few millilitres to rinse the stopper and inside of the neck of the apparatus, allowing the rinsings to run into the apparatus. Close by replacing the stopper and shake and invert repeatedly for 30 seconds. Do not shake too vigorously if centrifuging is not to be used in the following paragraph.
Allow the apparatus to stand until the upper liquid layer has become clear and is distinctly separated from the aqueous layer. Alternatively perform the separation by the use of a suitable centrifuge.
Note: when using a centrifuge not provided with a three-phase motor, sparks may occur and care is therefore necessary to avoid explosion or fire due to the occurrence of ether vapours, e.g. by a broken tube.
Remove the stopper, rinsing it and the inside of the neck of the apparatus with a few millilitres mixed solvent and allow the rinsings to run into the apparatus. Carefully transfer as much as possible of the supernatant layer by decantation or by means of a siphon into the flask (First para. of “Determination”).
Note: if the transfer is not made by means of a siphon, it may be necessary to add a little water to raise the interface between the two layers in order to facilitate the decantation.
Rinse the outside and the inside of the neck of the apparatus or the tip and the lower part of the siphon with a few millilitres mixed solvent. Allow the rinsings from the outside of the apparatus to run into the flask and the rinsings from the inside of the neck and from the siphon to run into the extraction apparatus.
Make a second extraction by repeating the procedure described in paras. 5 to 9 above 1 inclusive but using only 15 ml diethyl ether and 15 ml light petroleum.
Make a third extraction by repeating the procedure of para. 10 above but omitting the final rinsing (para. 9 above).
Note: it is not mandatory to carry out this third extraction in the case of skimmed milk powder.
Carefully evaporate or distil off as much solvent (including the ethanol) as possible. If the flask is of small capacity, some of the solvent will need to be removed in the above manner after each extraction.
1 numbering of paras. excludes “notes”.
When there is no longer any solvent odour, heat the flask, placed on its side, for one hour in the oven.
Allow the flask to cool to the temperature of the balance room as before (first para. of “Determination”), and weigh to the nearest 0.1 mg.
Repeat the procedure described in the two paras. above for heating periods of 30–60 minutes until the mass no longer decreases.
Add 15–25 ml light petroleum in order to verify that the extracted matter is wholly soluble. Warm gently and swirl the solvent until all the fat is dissolved.
When the extracted matter is wholly soluble in the light petroleum, the mass of fat is the difference between the weighings under paras. 1 and 15 above.
If not, or in case of doubt and always in case of a dispute, completely extract the fat from the flask by repeated washing with warm light petroleum, allowing the undissolved material to settle before each decantation. Rinse the outside of the neck of the flask three tlmes. Heat the flask, placed on lts side, for one hour in the oven, allow to cool to the temperature of the balance room as before (first para. above) and weigh to the nearest 0.1 mg. The mass of fat is the difference between the mass determined in para. 15 above and this final mass.
5.10.8 Expression of results
Calculation
The mass, in grammes, of fat extracted is:
(M1 - M2) - (B1 - B2)
and the fat content of the sample, in percentage by mass, is:
where:
M1 = mass, in grammes, of flask M with fat after stage in para. 15 of 5.10.7.
M2 = mass, in grammes, of flask M after stage in first para. of 5.10.7 or, in the case
of undissolved material, stage in para. 18 of 5.10.7.
B1 = mass, in grammes, of flask B of the blank after stage in para. 15 of 5.10.7.
B2 = mass, in grammes, of flask B after stage in first para. of 5.10.7 or, in the case
of undissolved material, stage in para. 18 of 5.10.7.
S = mass, in grammes, of sample used.
Repeatability of results
The difference between results of duplicate determinations (results obtained simultaneously or in rapid succession by the same analyst) should not exceed O.2 g fat for 100 g of the product.
Compositional Standard
5.11.1 General definition
Anhydrous milk fat, anhydrous butteroil or anhydrous butterfat, butteroil or butterfat, are products exclusively obtained from milk, cream or butter by means of processes which result in almost the total removal of moisture and solids-non-fat contents.
5.11.2 Essential composition and quality requirements
Anydrous milk fat
Definition: Anhydrous milk fat is the product obtained from fresh raw materials (milk, cream or butter) to which raw materials no neutralizing substances have been added.
| Milk fat: | 99.8 % minimum. |
| Moisture: | 0.1 % maximum. |
| Free fatty acids: | 0.3 % maximum (expressed as oleic acid). |
| Copper: | 0.05 p.p.m. maximum. |
| Iron: | 0.2 p.p.m. maximum. |
| Peroxide value (milli-equivalents of oxygen per kg of fat): | |
Note: this value and a method for the determination of this value are under consideration. According to Australian experience, a peroxide value of 0.1 maximum should be acceptable.
T.B.A. (Thiobarbituric acid) value:
Note: this value and a method for the determination of this value are under consideration. According to Australian experience, a T.B.A. value of 0.2 maximum should be acceptable.
| Coliforms: | absent in 1 g. |
| Taste and odour: | clean, bland (samples to be at a temperature of 20 to 25°C). |
| Neutralizing substances: | traces only. |
Note: the recommended physical structure should be in the form of a smooth, fine grain structure.
Anhydrous butteroil or anhydrous butterfat
Definition: Anhydrous butteroil or anhydrous butterfat is the product obtained from butter or cream, all of which can be of variable age.
| Milk fat: | 99.8 % minimum. |
| Moisture: | 0.1 % maximum. |
| Free fatty acids: | 0.3 % maximum (expressed as oleic acid). |
| Copper: | 0.05 p.p.m. maximum |
| Iron: | 0.2 p.p.m. maximum. |
| Peroxide value (milli-equivalents of oxygen per kg of fat): | |
Note: this value and a method for the determination of this value are under consideration. According to Australian experience, a peroxide value of 0.3 maximum should be acceptable.
T.B.A. (Thiobarbituric acid) value:
Note: this value and a method for the determination of this value are under consideration.
| Coliforms: | absent in 1 g. |
| Taste and odour: | not pronounced, unclean or other objectionable taste and odour. |
| Neutralizing substances: | traces only. |
Note: the recommended physical structure should be in the form of a smooth, fine grain structure.
Butteroil or butterfat
Definition: Butteroil or butterfat is the product obtained from butter or cream, all of which can be of variable age.
| Milk fat: | 99.3 % minimum. |
| Moisture: | 0.5 % maximum. |
| Free fatty acids: | 0.3 % maximum (expressed as oleic acid). |
| Copper: | 0.05 p.p.m. maximum. |
| Iron: | 0.2 p.p.m. maximum. |
Peroxide value (milli-equivalents of oxygen per kg of fat):
Note: this value and a method for the determination of this value are under consideration. According to Australian experience, a peroxide value of 1.0 maximum should be acceptable.
T.B.A. (Thiobarbituric acid) value.
Note: this value and a method for the determination of this value are under consideration.
| Coliforms: | absent in 1 g. |
| Taste and odour: | not too pronounced, unclean or other objectionable taste and odour. |
| Neutralizing substances: | traces only. |
Note: the recommended physical structure should be in the form of a smooth, fine grain structure.
5.11.3 Food additives
Permitted food additives:
sodium hydroxide;
sodium carbonate;
sodium bicarbonate;
antioxidants: any combination of propyl, octyl and dodecyl gallates, with butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT) or both. Maximum level for antioxidants: 200 mg/kg but gallates not to exceed 100 mg/kg.
5.11.4 Packaging requirements
The products shall be packed in airtight containers flushed with an inert gas prior to filling; residual head-space shall be flushed with an inert gas prior to sealing the containers.
Unless such containers are used, the products shall be transported and stored at temperatures not exceeding 10°C.
5.11.5 Marking and labelling
The containers, either large for commercial usage or consumer size packs, shall be clearly labelled with the designation of the product, net weight, country of origin, manufacturer's name and date of manufacture in either actual or coded form.
The presence of antioxidants shall be declared on the label and the generic name “antioxidants” may be used.
5.11.6 Methods of sampling and analysis
Sampling: according to FIL-IDF Standard 50.
Determination of fat content: according to FIL-IDF Standard 24.
Determination of moisture: according to FIL-IDF Standard 23.
Determination of free fatty acids: according to FIL-IDF Standard 6A.
Determination of copper: according to Standard.
Determination of iron: according to Standard.
Determination of peroxide value: according to Standard.
Determination of T.B.A. value: according to Standard.
Determination of coliforms: according to Standard.
Determination of foreign fats: according to FIL-IDF Standards 32, 37, 38 and 54.
5.12.1 Definition
Ghee is a product exclusively obtained from milk, cream or butter from various animal species, by means of processes which result in almost the total removal of moisture and solids-non-fat contents, with an especially developed physical structure.
5.12.2 Essential composition and quality requirements
| Milk fat: | 99.6 % minimum. |
| Moisture: | 0.3 % maximum. |
| Free fatty acids: | 0.3 % maximum (expressed as oleic acid). |
| Copper: | 0.05 p.p.m. maximum. |
| Iron: | 0.2 p.p.m. maximum. |
| Peroxide value (milli-equivalents of oxygen per kg of fat). | |
Note: this value and a method for the determination of this value are under consideration. According to Australian experience, a peroxide value of 0.5 maximum should be acceptable.
Physical structure: the product must consist of a mixture of higher softening point fats in crystal form dispersed through lower softening point fats in liquid form.
| Coliforms: | absent in 1 g. |
| Taste and odour: | the product should not have an objectionable taste and odour which does not meet edible requirements. |
| Neutralizing substances: | traces only. |
5.12.3 Food additives
Permitted food additives:
sodium hydroxide;
sodium carbonate;
sodium bicarbonate;
antioxidants: any combination of propyl, octyl and dodecyl gallates, with butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT) or both. Maximum level for antioxidants: 200 mg/kg but gallates not to exceed 100 mg/kg.
5.12.4 Packaging requirements
The product shall be packed in airtight containers flushed with an inert gas prior to filling: residual headspace shall be flushed with an inert gas prior to sealing the containers. Unless such containers are used, the product shall be transported and stored at temperatures not exceeding 10°C.
5.12.5 Marking and labelling
The containers, either large for commercial usage or consumer size packs, shall be clearly labelled with the designation of the product, net weight, country of origin, manufacturer's name and date of manufacture in either actual or coded form; in addition, the source of the milk (cow's, buffalo's, etc.) shall be clearly defined.
