126 Dairy Bacteriology. 



factories becomes a serious menace when fed to young 

 stock. To prevent distribution in this manner, compul- 

 sory legislation requires that the skim-milk shall be 

 pasteurized at a temperature of 176 F., in order to 

 destroy the bacilli. Storch has recently devised a test 

 that can be easily applied to milk to determine whether 

 such treatment has been carried out. It rests upon the 

 following principle: Milk contains a, certain substance, 

 (presumably an enzyme, 1 ) that decomposes hydrogen 

 peroxid. If milk is heated to 80 C. (176 F.,) or above, 

 this reaction ceases. When potassium iodid and starch 

 are added to unheated milk and the same treated with di- 

 lute hydrogen peroxid, the fluid assumes a blue color due 

 to the action of released iodin upon the starch. 



A striking illustration of the danger that may come 

 from a skim-milk-supply that is infected with disease bac- 

 teria is seen in the Welply epidemic of typhoid fever in 

 England in 1893, where twenty- three cases of this disease 

 developed in the families of patrons of a single factory, 

 the milk- supply of which became infected and was spread 

 by means of the skim -milk. 



Foot and mouth disease of cattle is often disseminated 

 in the same way. During the last decade, this disease 

 has been very severe in certain parts of Europe. The 

 virus of the disease can, however, be destroyed by the 

 use of heat. The regulation of the Prussian govern- 

 ment require milk of all diseased animals to be heated to 

 212 F. or to 194 F. for fifteen minutes. 



1 Storch believes it to be the unorganized ferment discovered in milk 

 by Babcock and Russell, 14th Wis. Expt. Stat., p. 77, 1897. 



