1028 BACTERIA IN AIR, SOIL, WATER, AND MILK 



its consumption. Though fresh milk possesses slight bactericidal 

 powers, 1 these are by no means sufficient to be of practical im- 

 portance in the inhibition of bacterial growth. Kept at or about 

 freezing-point, the bacterial contents of milk do not appreciably 

 increase. At higher temperatures, however, a rapid propagation of 

 bacteria takes place which, especially during the summer months, 

 speedily leads to enormous numbers. In a case reported by Park, 2 

 where milk, containing at the first examination 30,000 microorgan- 

 isms per cubic centimeter, was kept at 30 C. (86 F.) for twenty- 

 four hours, the count at the end of this time yielded fourteen 

 billions of bacteria for the same quantity. 



It is of much importance, therefore, that the cleanliness of dairies, 

 of cattle, and in the handling of milk should be reinforced by the 

 utmost care in chilling and icing during shipment and before sale. 



Because of its great importance, especially for the health of the 

 children in large cities during the summer months, the milk question 

 has, of recent years, received much attention from health officers. 

 In the city of New York, the question has been made the subject 

 of many careful studies by Park 3 and his associates. Commissions, 

 working in Chicago, 4 Boston, 5 and other large towns, have placed 

 the sale of milk under more or less exact bacteriological supervision. 

 Park has determined that the milk, as sold in New York stores 

 during the cold weather, not infrequently averages seven hundred 

 and fifty thousand bacteria per cubic centimeter; during the hot 

 summer months, the bacterial contents of similar milk not infre- 

 quently average one million and more, for the same quantity. 6 In 

 consequence of these and other researches, large dairies have intro- 

 duced bacteriological precautions into their method of milk produc- 

 tion. They have attempted the reduction of the bacterial contents 

 of milk by scrupulous cleanliness of the barns and of the udders 

 and teats of the cow, by the elimination of diseased cattle, by 

 sterilization of the vessels in which the milk is received, and of the 

 hands of the milker; also by the immediate filtering and cooling 

 of the milk and the packing of the milk cans in ice, where they 



1 Eosenau and McCoy, Jour. Med. Ees., 18, 1908. 



*Park, W. H., "Pathogenic Bacteria," New York, 1905, p. 463. 



3 Park, Jour, of Hygiene, 1, 1901. 



4 Jordan and Hcinemann, Rep. of the Civic Federation of Chicago, 1904. 



5 Sedgwick and Batchelder, Bost. Med. and Surg. Jour., 126, 1892. 

 *Escherich, Fort. d. Medizin, 16 and 17, 1885. 



