Introduction:
- Dairy microbiology may be defined as the branch of microbiology, which deals with the activities of the microorganisms in the milk and milk products.
- It includes the study of the morphology, classification and the chemical activities of microorganisms in the milk and milk products.
Sources of microorganisms in milk
The potential sources of bacteria are great because of their universal and natural presence in hays, feed, atmosphere and the soil. The different sources of contamination of milk are as follows:
- The udder of the cow: –
- The interior of the udder always contains microorganisms.
- The interior of the teats of the udder is warm, contains the last drop of milk following through it and hence serves the most ideal place for the growth of bacteria.
- The skin of the cow: –
- The coat of the cow presents an abundant surface for absorbing foreign materials.
- Commonly such adhering debris consist of soil, faeces, and dirt from the stable and so most of the bacteria that may come from this source are gas producers and putrefactive type.
- The faeces contains an enormous quantity of bacteria and so even a very small amount of dry faeces falling in milk would be enough to increase the number of bacteria in milk to great extent.
- Milking utensils: –
- There are two types of possibilities of contamination from this source.
a) The contamination may arise from the unsterilized milk utensils in which the type of bacteria may be lactic acid organisms.
b) It may be arise from the water with which the utensil was washed.
- Feed: –
- Since bacteria are found on vegetation and in the soil, they are abundant in the most of the cattle feeds.
- Air of the stable: –
- The air of the barn is usually heavily contaminated during mixing of dry feeds and during the process of cleaning the floor of the barn.
- Generally the air contains very little quantity of microorganisms.
6 Milers: –
- Bilker’s hands, cloths, health, habits and milking methods are responsible from milker source of contamination.