Introduction

• Milk is one of the best available complete food for human beings having a pH value of about 7 is one of the best available food, has high nutritive value.
• The average chemical composition of cow milk based on the analysis of a large no. of milk sample is as follows:

Water:                                                              87.0%

Lactose (Milk sugar):                                       5.0%

Casein (Milk protein):                                      2.5%

Lipid:                                                               4.0%

Albumin & other proteins:                               0.5%

Vit. A, D, E, & Sterols:                                      0.05%

Miscellaneous:                                                 0.95%

• There are various sources through which milk is contaminated. Milk is free of any microbes in udder of healthy cow but after milked the milk gets contaminated through various ways:

I.  Utensils

ii. Air borne micro-organisms settling into the milk

iii. Water

iv. Flank of cow, hands etc.

• Good quality milk contains low count of micro-organisms whereas poor quality contains large population of micro-organism.
• So, in order to get good quality milk, hygienic conditions are essential.
• The microorganisms present in the milk may be categorized into 3 groups:-

1. The normal micro flora of most of the milk samples.
2. Some spoilage microorganisms which gain entry into the milk through various sources.
3. Some pathogenic microorganisms (to both man and animal) that may be present in unhealthy cow.