Milk Products What is your comment on the

Milk Products

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Milk products include: v Cream v Butter v Ghee v Cheese v Concentrated milk v Milk powder v Ice cream v Fermented milk

1 - Cream �Definition: Cream is that portion of milk, rich in milk fat that rises to the top of milk while it is standing. Or Cream is that portion which could be separated from milk by means of centrifuges called separator. Or Concentration of fat globules of milk, which has been separated by skimming or otherwise.

Sampling: Sample should be Representative {for bulk of cream being examined} Taken from dairy & retail premises Mixed by dipper, stirring, or agitation

ü All equipment must be ---clean, dry, for physical examination. ---and sterile for microbiological examination. ü Bulk: - cream is properly mixed. - take about 250 -500 gm & put them in a dry clean, wide mouth bottle/jar. - bottles/jars are corked tightly , labeled. - then either examined directly kept at refrigerator. or

�Bottles & Cartons(packages): - one or more bottle / cartons obtained as random sample. - examined in the same day (avoid enzymatic deterioration)

Preparation of sample: v In case of Thick cream : warmed in water bath at 40°C for 10 minutes with thoroughly mixed till be homogenized without separation of fat. v In case of light cream : thoroughly mixed only.

Examination �Physical examination: examined for flavor, color, consistency. �Chemical examination: Determine fat% lactose content. Ash content. Lactose content. protein content. T. S & moisture content. adulteration of cream.

�A)- Determination of fat content: a. Gerber method : using cream or milk butyrometer. a 1)Gerber method using cream butyrometer: -in cream butyrometer add: * 10 ml Gerber H 2 so 4. * 1 ml amyl alcohol. * 5 gm cream sample + 6 ml worm D. W. - mixing thoroughly. - complete as milk. Cream Butyrometer 0 -70%

a 2) Gerber method using milk butyrometer: -in milk butyrometer add: * 10 ml Gerber H 2 so 4. * 1 ml amyl alcohol. * 1 gm cream sample + 10 ml worm D. W. - mixing thoroughly. - complete as milk. - record reading ( R). �Calculation fat% = (R X 10. 92)+ 0. 46 Wt of cream used

b. Rose Gottlieb method: - 1 gm cream sample + 10 ml worm D. W. - complete as in milk. c. Soxhlet method: - in case of thick cream using 5 gm of sample. • B) Protein content: • C) lactose content: • D) Ash content: • E) T. S & moisture: by Kjeldahl’s method. (2. 2%) as milk. (3. 15%) by muffle furnace. (0. 46) as milk * 2 gm cream sample are placed on previously weighed dish + 2 ml of D. W. * make evaporation till dryness---- complete as milk

�F) detection of cream adulteration: cream is adulterated either by addition of Thickeners Coloring matter preservatives A) Thickeners: * Definition: It is a substance added to increase viscosity of cream. *examples: using of gelatin – starch – agar or foreign fat as coconut oil or hydrogenated oil.

� Gelatin ** procedure: -In a beaker (clean, dry, sterile) add: . 10 gm cream. 20 ml worm D. W. 10 ml acid mercuric nitrate solution. - vigorously shaking. - left for 5 min then filtered. ** Result: filtrate clear filtrate turbid -ve +ve ** For confirmation: - take equal amounts of filtrate & picric acid saturated solution (test tube) - shaking - appearance of yellow color or PPt +ve for gelatin.

�Starch: ** procedure: -In a beaker (clean, dry, sterile) add: . 1 gm cream. 5 ml worm D. W - mixing - transfer to boiling water bath for 5 min. - cooling - add Iodine solution ( drop by drop ). ** Result: developing of blue color +ve for starch.

� Agar agar ** procedure: -In a beaker (clean, dry, sterile) add: . 50 gm cream. 100 ml worm D. W. 10 ml calcium chloride (cacl 2) 10%. - shaking. - filtrate. - dissolve the curd in alcohol. - evaporate alcohol. ** Result: gelatinous mixture +ve for Agar agar.

�Foreign fat Soxhlet method make extraction of fat by Rose Gottleib method - physical & chemical &and specific tests are carried out as in fat & oil.

� B)Detection of coloring matter : as: - Aniline Annatto Tar derevatives Carotine( plant origin) Poisonous Not poisonous Dissolve in acetic acid Not dissolve in acetic acid *procedure: In a beaker (clean, dry) add: . 5 gm cream. 5 ml worm D. W. 1 ml glacial acetic acid ( for coagulation of protein) - shake properly & then transfered to water bath at 70°C with continous agitation till PPT of all protein ( formation of curd). - cooling - filtration to separate curd from filtration. *Result: - filtrate has yellow color * curd has yellow color * +ve (aniline is added) +ve ( annatto or carotine is added)

�To be sure : - in flask( 50 ml ether +curd) >>dissolving to fat. - shaking of flask & left overnight till formation of two layers. - decante ether extract to an evaporating dish. - after evaporation of ether , add few drops of Na. OH to thr residue. - residue is poured over a moist filter paper. *Result: formation of straw color small spots >>> annatto is added. �To be sure: Drying to filter paper & then add drops of stannus chloride solution pink color annatto Yellow color carotine

�Sanitary test : ** procedure: -In a beaker (clean, dry) add: . 5 gm cream. 5 ml worm D. W. 1 ml Ph. Ph solution. - mixing - titration against Na. OH N/9 till reaching end point ( appearacce of faint pink color ) - record reading (R ). **calculation: Acidity % = R/10 (( must be not more than 0. 15% )) Acidity degree = R X 10 **Legal requirement : 0. 14 -0. 20 %