EXPERIMENT STATION WORK RELATING TO PURE MILK, 



297 



cleaned in the ordinary way and another pail of the same kind was 

 sterilized with steam for half an hour. Milk was then milked into 

 the two j)ails under conditions as nearly identical as possiblr. The 

 milk in the sterilized pail was fovmd to contain IGo bacteria per 

 cubic centimeter, while the milk in the pail cleaned in the ordinary 

 way contained 4,*2Gr> per cubic centimeter. The milk in the sterilized 

 pail remained sweet five and one-half hours longer than the milk in 

 the other pail. 



Data upon the value of washing powders for disinfecting dairy 

 utensils were reported by Doane," and a very recent bulletin by Erf 

 and Melick ^ contains, in addition to practical suggestions on the care 

 of dairy utensils, the results of a number of experiments in cleaning 

 separators. Some of the conclusions are here quoted : 



A cream seir.irator should bo thoroughly washed every time after using. A 

 brush should be u.sed on every part aud piece, using 5 per cent solution of Itorax 

 or other good washing powder. Rinse in hot water or steam if possible. They 

 should then be left to dry while hot. Wiping with an ordinary clean cloth 

 contaminates utensils with innumerable bacteria. 



The bacterial contamination in milk is increased from three to five times by 

 running it through a separator bowl which has been used aud only flushed 

 and left standing several hours. If only flushed while using, for several days, 

 the contamination increa.ses several times more, and such milk would be likely 

 to be detrimental if fed to calves. 



The destruction of bacteria in milk by means t)f heat has been dis- 

 cussed in station bulletins of a more or less popular nature by Rus- 

 sell,*^ Smith,'' Marshall,'^ Emery,^ Nelson,^ and others. In some of 

 these bulletins new forms of pasteurizing apparatus have been de- 

 scribed and tests of their efficiency reported, Farrington and Rus- 

 sell ^ and Harding and Rogers * have reported tests of pasteurizers 

 under practical conditions. Aside from the effects of pasteurization 

 in reducing the bacterial content of milk, the influence of heat upon 

 the composition and properties of milk has received some attention 

 by station workers, and along this line the investigations at the Wis- 

 consin Station ■' are the most prominent. These have included studies 

 of the effects of pasteurization upon the viscosity of milk and upon 

 the proteids and fat globules. 



The principal argument offered for the pasteurization of pui)lic 

 milk supplies has been the destruction of pathogenic bacteria, espe- 

 cially the tubercle bacillus. An low a temperature as is possible to 



o Maryland Sta. Bui. 79, 

 6 Kansas Sta. Bui. 1.31. 

 <• Wisconsin Sta. Bui. 44. 

 'I.Michigan Sta. Bui. 1.34. 

 f Michigan Sta. Buls. 147. 



r 



/ North Carolina Sta, Bui, 148. 



ffNew Jersey Stas. Bui. I.n2. 



* Wisconsin Sta. Bui. (J9. 



* New York State Sta. Bui. 172. 



y Wisconsin Sta. Hpts. 1,S0.">. pi). 98, HU ; 

 189G, p. 73; 1899, p. 129. 



