536 MILK 



proprietary foods, 19 per cent, to sterilized milk, 10 per cent, 

 to condensed milk, 3.5 per cent, to breast milk, and 4.5 per cent, 

 to pasteurized milk. These figures speak for themselves. 



It is said that pasteurization encourages filthy production, 

 and that the day is deferred when clean, raw milk — termed by 

 Nathan Straus an "elusive ideal" — will be the common market 

 milk. It is said by some that the producer will consider care and 

 cleanty habits superfluous if he knows his milk is to be pasteurized 

 anyhow. Perhaps this objection would not be wholly without 

 foundation if it were proposed to pasteurize any kind of milk. 

 Attention has been called to the necessity of dairy inspection 

 which should ehminate milk from producers whose score is less 

 than 55 on the government score card. If efl[icient inspection is 

 carried out in conjunction with pasteurization this objection 

 cannot hold. 



"Life" in milk is destroyed, according to some objectors, 

 "life" in milk is obviously a loose term, and usually refers to the 

 presence of enzyms in milk, whether these are native enzyms or of 

 bacterial origin. Whether milk enzyms are of use in aiding diges- 

 tion of milk has never been determined, but admitting the pos- 

 sibility, enzyms in cow's milk were not intended by nature for 

 babies. If it can be shown that they are of benefit for calves, 

 no proof is implied that they are of benefit to human beings. 

 Besides, heating milk to 60° C. for thirty minutes does not destroy 

 enzyms; most of them are not affected and only a few are weak- 

 ened. These are reductases and catalases and have no concern in 

 digestive processes. 



The effect of the temperature and holding period of pasteur- 

 ization on enzjons and some of the most important pathogenic 

 bacteria has been graphically illustrated by North in the chart 

 (Fig. 218). 



The statement is sometimes made that vitamins are destroyed 

 by pasteurization. Vitamins seem to be essential for reproduc- 

 tion and development, but scientists are still ignorant of their 

 nature. They are widely distributed, especially in some foods, 

 such as milk and eggs, and also in the leaves of plants. Two 

 types of vitamins are recognized. One of these types is fat- 

 soluble and is present in some fats, notably butter-fat and the fat 

 from the yolks of eggs. It is contained also in other substances, 

 as in alfalfa leaves for example. The other type is water-soluble. 

 According to Hart and Steenbock, the water-soluble vitamin is 

 present in milk, eggs, grain, the leafy portions of plants, and in a 

 very limited degree in polished rice. It can be obtained by ex- 

 tracting these substances with water. Both vitamins are neces- 

 sary for normal growth, but experiments made by Hart and 



