METHODS OF REDUCING THE GERM CONTENT 529 



4. After pasteurization the milk should be cooled to 50 F. 

 or below, and kept cool until delivered. 



5. Automatic devices for recording the exact temperature of 

 the milk during pasteurization should be installed with each 

 machine. These devices should be kept locked and remain inac- 

 cessible to any one but the deputy of the health department. 

 Both the temperature and the period of holding should be recorded, 

 and it is advantageous to have a temperature recorder both be- 

 fore the milk enters and after it leaves the holding system. 



6; The efficiency of pasteurization should be controlled by 

 bacterial enumeration. As previously stated, definite percentage 

 standards are of little value, since in a milk of high bacterial con- 

 tent a higher percentage is destroyed than in one containing few 

 bacteria. Comparative counts of bacteria before and after pas- 

 teurization will, however, aid in proper control of the process. 



7. After pasteurization milk should receive as much care as 

 raw milk. 



8. Consumers are entitled to know they are receiving pas- 

 teurized milk and the day when it was pasteurized. The fact 

 that the milk has been pasteurized and the date of pasteurization 

 should be indicated on the bottles. 



Evidence that pasteurized milk is beneficial to public health 

 is difficult to gather. Introduction of pasteurization is a slow 

 and gradual process and one that is not easily controlled, because 

 milk is assembled from many sources. However, a few indica- 

 tions of benefits derived are available. Thus Jordan states that 

 typhoid fever is more prevalent in cities of the United States than 

 in European cities, even when American cities have good water- 

 supplies. He ascribes this to the common custom in Europe of 

 heating milk before its consumption. Rosenau, Lumsden, and 

 Kastle, after investigating the causes of typhoid fever in Washing- 

 ton, D. C., found that the lowest percentage of cases was among 

 customers of the only dealer who pasteurized the milk and steril- 

 ized the bottles. Straus states that before distribution of pas- 

 teurized milk for infant feeding in New York City, the death-rate 

 among children below five years was 96.2 per 1000 per annum and 

 136.4 per 1000 in June, July, and August. After distribution of 

 pasteurized milk the death-rate fell to 55 per 1000 per annum and 

 62.7 during the summer. It is probable, however, that the good 

 results were not wholly due to pasteurization. Important acces- 

 sory factors here were the limited quantity given each baby and 

 the instructions tendered the mothers as to the care of the baby. 



Pasteurization of milk is of immense importance in the hand- 

 ling of skimmed milk from creameries and whey from cheese fac- 

 tories. These by-products frequently contain tubercle bacilli and 



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