The principle of cold storage is founded on this fact. A whole chapter could be written on the care of milk. The average man of the present day who can afford ice promptly places his daily supply in the ice box as soon as it is received. The intelligent milk dealer knows that it is good business as well as good sanitation to keep his product as cold as possible until delivered. He knows that if this product is not produced in clean dairies that the chances are that it will be far on the road to turning sour by the time he receives it and that the householder will not pay him for sour milk when he ordered sweet.
Milk is an animal product and as such is quickly invaded by bacterial life.
These-tiny organisms increase by the billion in milk which is not cooled properly after milking. They produce acid very rapidly when the temperature is favorable and the result is sour milk. Fortunately for us, milk does not often contain the former varieties. There is, however, a chance that it may and for this reason bacteriologists insist that milk shall contain as few bacteria as is humanly possible. Therefore there are two good reasons for demanding what is known as a low bacterial count in milk.