184 BACTERIA IN AIR, SOIL, WATER AND MILK 



spores of putrefactive bacteria, which are of little danger if 

 the milk be kept on the ice or used shortly. Some persons 

 object to the use of this heating because the food value of 

 the milk is reduced by making certain chemical constituents 

 harder to digest. The casein curds- of milk become tougher 

 after boiling. There seems to be no proof for the statement 

 made in certain quarters that Pasteurization causes the 

 elaboration of poisonous substances in milk. Indeed, some 

 pediatrists are now using boiled cows' milk for certain intes- 

 tinal disorders of children. If properly carried out, Pas- 

 teurization does more good than harm, and has proved its 

 value by the reduction of the death-rate from infantile diar- 

 rhea in summer time. The greatest objection anyone can 

 raise to Pasteurization is that it gives a false sense of security. 

 It cannot be too strongly emphasized that any natural anti- 

 bacterial power possessed by the raw milk or the restraining 

 influence of lactic acid bacilli on putrefactive bacteria is 

 destroyed by Pasteurization and that rigid precautions 

 should be observed that the heated milk is not allowed to 

 remain at a temperature permitting the growth of bacteria. 

 If kept below 60 F. and used within twenty-four hours the 

 consumer is probably safe at all times. 



Spoiling of Milk. In the summer conditions for the spoil- 

 ing of milk are more favorable than in winter, since the tem- 

 perature is unfavorable for its preservation, and more dust 

 and flies introduce bacteria. Bottles in which milk is served 

 should be washed when empty, with cold water first, and then 

 boiled or well scalded. If a small quantity of milk remain 

 in the bottom, putrefactive and fermentative bacteria grow 

 and dry on the bottle, making it harder to clean subsequently. 

 Milk bottles should be considered as possible carriers of dis- 

 ease and the user should assume his part of the responsibility 

 by cleaning them out and not leave it entirely to the milkman. 

 The author knows of one instance where a milk bottle was 

 used as a spittoon. 



