Milk readily absorbs odors, flavors and impurities; it is one of the best of soils for the growth and multiplication of certain disease germs. Bacteria are introduced from dust arising from the cow's body, from the clothing or hands of the milker, from the milk vessels, or from the water in which these have been washed. The bacteria of typhoid fever, diphtheria and tuberculosis may be transmitted in this way. Once admitted to the milk, they begin to multiply: warmth is favorable to their growth, hence it is desirable to cool milk soon after it is drawn and to keep it at as low a temperature as possible. The souring of milk in a thunderstorm is due, not to the storm, but to the warm sultry weather preceding, which is favorable to the growth of bacteria. If kept thoroughly chilled milk is not affected by storms. Besides being kept cool, milk that is delivered in bottles and stored in refrigerators with other food should be tightly sealed. If the bottles are to be opened several times and the caps cannot be replaced, close the neck of the bottle with cotton. Since most disease germs are destroyed by heat, at the temperature of boiling water, milk may be made free from all living organisms - such milk is said to be sterile.

Scalding Milk

The digestibility of albumen in milk, as in all other substances, is diminished when it is heated to the boiling point; on this account in cookery milk is scalded rather than boiled. This is done best in a double-boiler. The milk is scalded, when small bubbles appear on the surface next to the vessel. The temperature is about 160° Fahr. If put directly over the fire and left, milk is liable to boil over. Milk contains so much solid matter that, in boiling, the bubbles below are of such consistency that they hold up those above, or bubbles are piled up on bubbles until the dish overflows.