Alcohol Test in Milk

Alcohol test is done to check the stability of milk.

1.Take 5 ml of milk in a petri dish.

2.Slowly add 5 ml 68% ethanol in the milk.

3.Check if there is any curdling or precipitates.

Acidity in Milk

1.Take 10 ml of milk.
2.Add 3-4 drops of 1% Phenolphthalein indicator.
3.Titrate with 0.1 N NaOH.
4.Note down the titre value at the end point i.e. light pink colour.

Acidity(% Lactic Acid)=  9*Titre Volume*Normality/Volume of Milk Sample

Estimation of Fat in Milk using Gerber Method

Gerber Method is most widely used method for the estimation of fat in Milk.The procedure is as follows:-
1. Take a clean and dry Butyrometer and pour 10 ml 90% Sulphuric Acid.
2.Now slowly add 10.75 ml of milk using pipette.
3.Now add 1 ml of Amyl Alcohol and seal the butyrometer with rubber stopper.
4.Put the butyrometer in the centrifuge and centrifuge at 2000 rpm for 5 minutes.
5.After 5 minutes, Fat being ligher,makes the upper layer. Note down the reading of fat on graduated Butyrometer.This is the total %age of fat in milk.

Estimation of fat in Paneer and SMP can also be done using same method. For Paneer sample amount should be lesser(3-5 gms).Use calculation as follows:-

        %age Fat =Reading*11.21/sample Weight
               
                                     

Calibration of TDS/Conductivity Meter

1.Preparation of Calibration solution-
   Prepare 1000 ppmn solution of NaCl (Sodium Chloride or Table Salt).For this take 1000 mg or 1 gm Nacl in a 1000 ml volumetric flask and dissolve in small quantity of water.Make up to the mark.Also make a dilution of 500 ppm NaCl by taking 50:50 Distilled Water and 1000 ppm NaCl.One can also use KCl(Potassium Chloride) in place of NaCl.

2.Dip the electrode of TDS meter into 1000 ppm and 500 ppm NaCl solution.If meter is showing the different results then set the value to the known concentration i.e. 1000 ppm or 500 ppm.

3.Now take the reading of the sample.