EXPERIMENT STATION WORK RELATING TO PURE MILK. 295 



oiisly. After twelve hours the teats were disinfected and the milk 

 drawn and examined bacteriolooically. The experiment was repeated 

 each day for five days. Negative results were obtained in every case. 



AVhile these experiments with one cow failed to show that bacteria 

 may pass from the drinkin<>; water to the milk or that typhoid bacilli 

 may enter the udder throu<^h the teats, they do not necessarily assure 

 negative results with all cows, and so shouUl not encourage the use 

 of polluted water. The results indicate, according to the author, 

 that nature has provided some means of preventing germs from 

 entering milk, which should be supplemented by providing the 

 purest water obtainable and by fencing off stagnant water ponds. 



The nuiin bacterial contaminations of milk occur, therefore, after 

 the milk leaves the udder, the largest amount being doubtless at the 

 time of milking, and investigations along this line have been previ- 

 ously referred to. Conn and his associates at the Connecticut Storrs 

 Station have studied the sources of bacteria in milk, described and 

 classified numerous sjjecies found in milk, devised methods of bac- 

 teriological analysis, and reported extended studies of the growth 

 and behavior of bacteria in milk. 



Some of the results reached at this station are embodied in a 

 recent bulletin," Avhich emphasizes not only the importance of pre- 

 venting bacterial contamination by cleanliness at every stage, but 

 the value of low temperatures in preserving milk. The following is 

 quoted from this bulletin on account of the caution there raised 

 against the use of old milk : 



Although the temperature of 50° F. is to he emphatically recommended to 

 the dairyman for the purpose of keeping his milk sweet and in proi)er condition 

 for market, he must especially I)e on his guard against the feeling that milk 

 which is several days old is [iroper for market, even though it is still sweet and 

 has not curdled. Quite the reverse is the case. Old milk is never wholesome, 

 even though it has heen kept at a temperature of 50° and still remains sweet 

 .^nd uncurdled. This very considerai)ly modifies some of our previous ideas 

 concerning milk, for it has heen generally helieved that so long as the milk 

 remains sweet it is in good condition for use. Quite the contrary is the case, 

 if it has heen kept at a temperature of 50° or in this vicinity. It is not unlikely 

 that it is this fact that leads to some of the cases of ice-cream poisoning, so 

 connnon in snnuner. The cream is ki'i)t at a low temperature for several days 

 until a considerahle quantity has accunudated or a demand has come for ice 

 cream, and when made into ice cream it is filled with hacteria in great numhers 

 and of a suspicious character. 



Several abnornuil fermentations of milk have been reported in 

 station pui)lications. The presence of gas and taint-producing bac- 

 teria has been observed at the AVisconsin,'' New York,*^ Iowa,'' and 



a roimecticut Storrs Rta. Rnl. 20. 



6 Wisconsin Sta. I?ul. (I'J, lliS ; Upt. l.S'.)5, pp. 127, Mil. 



cNew York Cornell Sta. Bui. 158; New York State Sta. lUil. ia3. 



rf Iowa Sta. Bui. 34. 



