Types of bacteria found in milk and milk products are:
The acid producing bacteria: These bacteria are responsible for conversion of lactose to lactic acid. Bacteria included in this group are: Streptococcus lactis, Streptococcus cremoris, Lactoba-cillus acidophilus, Lactobacillus bulgaricus.
Aroma producing bacteria: These bacteria are responsible for the production of desirable aroma and flavor in milk product. By utilizing citric acid and lactic acid they produce volatile acid such as acetic acid as well as diacetyl and other compound, which gives flavor and aroma.
Eg.Streptococcus citrovorus : Streptococcus paracit-rovorus, Streptococcus diacetilactic.
Gas producing bacteria: These are undesirable type of bacteria that ferment lactose and produce acid and gas i.e, lactic acid and carbon dioxide. Eg. Coli, Aerobacter acrogens
Peptonizing type of bacteria: These bacteria show tendency to break down the casein by a proteolysis or peptonization, which gives off flavor and unpleasant Odors in milk.
Eg. Bacillus subtilis, Bacillus mesentericus, Bacillus mycoides, Bacillus noves
Ropiness type of bacteria: These organism form gum like substances. Eg. Alligenes viscosus, Alcaligenes viscolactis bacteria found in milk.