THE MILK SITUATION IN THE DISTRICT OF COLUMBIA. 89 



to the time of their manufacture, at a temperature not in excess of 

 50 F. There would appear to be no reason for a similar specifica- 

 tion concerning buttermilk. 



FREEZING OF MILK. 



The committee has examined with interest a report by United 

 States Consul T. H. Norton (Appendix AK) of an address" by Prof. 

 Hempel on the " Treatment of Milk " before the seventy -ninth an- 

 nual meeting of the German Association of Scientists and Physicians, 

 held at Dresden, Saxony, in September, 1907, discussing the feasi- 

 bility of transporting and delivering milk in a frozen condition. Ex- 

 haustive experiments have shown conclusively, Consul Norton states, 

 that pure milk when frozen preserves its original properties un- 

 changed for weeks. Frozen specimens, kept for over a month in the 

 refrigerating room, showed on thawing absolutely no alteration in 

 taste, while the fact of a considerable diminution in the number of 

 bacteria present was clearly established. Important also, he con- 

 tinues, was the circumstance that while frozen the cream remained 

 evenly diffused throughout the solidified mass, which is not the case 

 when milk is kept at a low temperature in a liquid state. To attain 

 good results, he adds further, it is essential that pure, fresh milk, as 

 soon as collected from the animal, be rapidly cooled to the freezing 

 point. Dirty and contaminated milk, as well as milk in which the 

 lactic fermentation has begun, after being frozen, curdles upon melt- 

 ing. He offers the suggestion that fresh milk could be irozen in 

 the proper containers by submerging them in brine chilled far below 

 the melting point of ice, and that, when the milk has not only been 

 frozen, but cooled still further to the temperature of the surround- 

 ing liquid, the flasks or other containers could be removed, inclosed in 

 felt protectors, and conveyed to the consumer. Frozen milk prepared 

 under such conditions will, he contends, remain in a solid state for 

 a day or more before the temperature of the entire mass can rise to 

 the melting point. He further remarks that refrigerator cars would 

 obviously be unnecessary for the transportation of milk in this form, 

 unless unusually long distances are to be traversed. The compara- 

 tively small cost of freezing and chilling the milk supply of a city 

 would, he asserts, be more than offset by economy in transportation, 

 by the utilization of remote and inexpensive pasturage, and by the 

 removal of one of the gravest causes of infant mortality. 



There is considerable diversity of opinion as to the effect produced 

 by freezing on the qualities of 'milk. Of 24 expressions of opinion 

 on the subject, the committee finds 3 proponents of the belief that 

 freezing has no effect whatsoever, while 5 of the authorities consulted 

 maintain that the prejudicial effect is slight, if appreciable at all. 

 Surg. Gen. Stokes claims that freezing has little or no influence, 

 while Surg. Gen. Torney says that the effect is not injurious unless 

 the freezing be long continued, when it would probably diminish the 

 germicidal power of the milk. According to Dr. Melvin freezing 

 has the effect of separating the butter fat and causing the fat glob- 

 ules to collect into granules. Dr. Duncan, bacteriologist and chief 

 inspector of the health department of Birmingham, Ala., contends 

 that it changes the character of milk slightly, and that it is not 

 always possible to insure a good quality of milk after melting. This 



