MILK AND ITS PRODUCTS 201 



Typhoid fever, scarlet fever, diphtheria, foot and mouth 

 disease, cowpox, anthrax, and glandular tuberculosis are 

 some of the forms of diseases that are known to be occasioned 

 by the use of infected milk. 



Milk is so liable to become a source of danger as a food 

 that all well-governed cities have placed the milk supply 

 under government inspection. In many cases this control 

 is so efficient that milk obtained in the city is safer and better 

 than that obtained in the country. To pass the inspection 

 the farmer is compelled to deliver a purer and higher grade 

 of milk for city markets. The New York Board of Health 

 have ruled that milk containing more than 88.5 per cent 

 of water or less than 3 per cent of fat or less than 11.5 

 per cent of solids cannot be offered for sale legally in that city. 

 The Boston Board of Health prohibits the sale of milk con- 

 taining more than 500,000 bacteria per cubic centimeter or 

 which is delivered at a temperature higher than 50 F. 



149. Preservatives. Milk becomes infected a short time 

 after production. If the use of the milk as a food is delayed, 

 bacteria increase to inconceivable numbers. At the temper- 

 ature of the human body (98.6 F. or 36 C.) one bacterium 

 in milk will multiply to 75,000 in twenty-four hours. If the 

 temperature is reduced to 50 F. bacteria will increase very 

 slowly, if at all. All bacteria are not dangerous; some 

 species are friendly, aiding in the processes of digestion and 

 assimilation. There are three ways of controlling the num- 

 ber of bacteria: First, by preventing as far as possible 

 infection, by healthy cows, cleanly methods of production 

 and handling and control of temperature; second, by treat- 

 ing the milk by sterilization or pasteurization and then guard- 

 ing against further infection ; third, by adding to the milk 

 some preservative which is germicidal. The last of these 

 methods is to be condemned. Some preservatives are 

 harmful, and all serve to preserve the milk by producing con- 

 ditions that are not conducive to easy digestion. Formalin, 

 which is a 40 per cent solution of formaldehyde (HCHO), 



