Definition : Addition or removal of legally prohibited substances from the milk with the view to
increase quantity and reduce the quality to make extra profit.
Common adulterants :
1. Addition of water
2. Removal of fat.
3. Addition of starch
4. Addition of milk powder
5. Addition of carbonate and bicarbonate.
The practice of adulteration of milk is a reality. It is paradoxical that human instinct for
greed so far as to touch the precious food meant to protect the health of vulnerable groups of
infants, children and the elderly. Some of the known adulterants are water, salt, sugar, wheat,
starch, washing soda, formalin, urea, hydrogen peroxide etc. Some are used for increasing
volume and SNF content of milk while others as preservatives to extend shelf life.
Detection of adulterants
Detection of water : water is a most common adulterant and its presence can be detected
by testing the freezing point of milk. The official method of AOAC assumes a freezing point
for normal milk of –0.550oC
0.55-xt
Percentage added water = –––––––– x 100 where x is freezing point depression.
0.55
A tolerance of 3% is allowed which is equivalent to specifying a minimum freezing point
depression for authentic milk of 0.5335oC. The presence of water can also be checked by the use
of lactometer.
