428 MILK 



Bacillus coli does. There are, however, other spore-bearing bac- 

 teria in milk which grow both aerobically and anaerobically, and 

 if spores of these are present in large numbers the characteristic 

 reaction of Bacillus sporogenes may not appear. 



SAMPLING MILK FOR BACTERIOLOGIC EXAMINATION 



A representative sample of milk for bacteriologic examination 

 is of the utmost importance, because many types of bacteria 

 thrive in milk and the flora changes rapidly numerically and in 

 kind. Samples should be taken from well-mixed milk only, and 

 if possible plated immediately, or smears made for the micro- 

 scopic count. If transportation is necessary, the samples should 

 be kept cool. Conn has stated that if a sample of milk is kept in 

 ice water the bacterial count after twenty hours is but slightly dif- 

 ferent from the one made of the fresh sample. 



Samples can be taken in bottles or test-tubes and can be kept 

 cool in one of the many devices obtainable for the purpose. 



Care should be taken that the cream is thoroughly mixed with 

 the milk before sampling. As explained in a previous chapter, 

 cream is liable to become stiff when cold and mixes readily only if 

 warmed. The importance of this is evident considering the fact 

 that bacteria rise with the cream by adhering to the fat globules. 



BIBLIOGRAPHY 



American Public Health Association: Standard Methods for the Bacterial 

 Examination of Milk, 1916. 



Ayers: Jour, of the Amer. Pub. Health Assoc., 1911, vol. 1, p. 891. United 

 States Dept. of Agri., B. A. I., 28th Annual Report, 1911. 



Ayers and Clemmens: United States Dept. of Agri., Bull. 739, B. A. I., De- 

 cember, 30, 1918. 



Ayers and Johnson: United States Dept. of Agri., B. A. I., Bull. 161, March, 

 1913. Jour. Agri. Research, 1915, vol. 3, p. 401. 



Barthel: ReVue" Gen. du Lait, 1906, vol. 5, Nos. 10, et suiv. 



Breed: Cent. f. Bakt., Abt. 2, 1911, vol. 30, p. 337. 



Breed and Brew: New York Agri. Exper. Sta., 1916, Tech. Bull. 49. New 

 York Agri. Exper. Sta., Bull. 443, December, 1917. 



Breed and Stocking: Jour, of Dairy Science, 1917, vol. 1, p. 19. 



Brew: New York Agri. Exper. Sta., Bull. 373, February, 1914. 



Brew and Dotterer: New York Agri. Exper. Sta., Bull. 439, November, 1917. 



Conn: United States Public Health Reports, August, 1915, Reprint, 295. 



Freas: Amer. Jour, of Pub. Health, 1905, vol. 5, p. 1035. 



Frost: Jour. Amer. Med. Assoc., 1916, vol. 66, p. 889. Jour. Infect. Dis- 

 eases, 1916, vol. 19, p. 273. Proceedings of the Ninth Annual Conven- 

 tion of the International Milk Dealers' Association, held in Springfield, 

 Mass., 1916, pp. 63, 78. Jour, of Bacteriology, 1917, vol. 2, p. 567. 



Heinemann and Glenn: Jour. Infect. Diseases, 1908, vol. 5, p. 412. 



Hunter: Jour, of Bact., 1917, vol. 2, p. 635. 



Johnson and Levine: Jour, of Bact., 1917, vol. 2, p. 379. 



Jordan, E. O.: Jour. Amer. Med. Assoc., 1917, vol. 68, p. 1080. 



Prescott: Proceedings of the Sixth Annual Convention of the International 

 Milk Dealers' Association, held in Chicago, 111., 1913, p. 36. 



