THE PASTEURIZATION OF MILK 505 



and that no fermentative, putrefactive, or similar processes can 

 occur in it. It has been shown how bacterial culture media are 

 sterilized so that they may be used for the development of pure 

 cultures. Organic material in general and certain foodstuffs, par- 

 ticularly meat and milk, are excellent soils for the development of a 

 host of microorganisms. Their growth may so change foodstuffs that 

 they become unfit for food both on account of features repulsive to 

 our senses and because they may actually contain dangerous poisons. 

 It has been long known that low temperatures largely prevent putre- 

 factive processes, and it had also been observed that high temperatures 

 may be used for the same purpose. The Japanese have, for a long 

 time been in the habit of heating their rice wine or sake in spring to 

 preserve it during the summer. When Pasteur studied the changes in 

 wine and beer, known as the diseases of wine and beer, due to certain 

 microorganisms which develop subsequent to the alcoholic fermenta- 

 tion of the yeast cells, or saccharomyces, he tried to devise a means 

 of checking such undesirable growth. As he had finally successfully 

 shattered the old ideas of spontaneous generation, and demonstrated 

 the requirements of reliable, absolute sterilization, the latter pro- 

 cedure at once suggested itself. It was, however, soon found that 

 sterilization could not be employed to protect wine or beer against 

 undesirable microbic multiplication and changes, because it destroyed 

 certain valuable properties in these beverages and was too expensive 

 on account of the excessive breakage of closed filled bottles exposed 

 for a considerable time to the action of the temperature of boiling 

 water or steam. Pasteur then devised methods of using temperatures 

 considerably below the boiling point for certain periods of time, 

 which while not producing absolute sterilization, killed most micro- 

 organisms and produced conditions under which articles of food 

 acquired more stable keeping qualities. This process is now generally 

 known as pasteurization. After medical bacteriology had become 

 firmly established by the work of Robert Koch the dangers which 

 might lurk in infected milk were not only clearly recognized, but 

 were for a time much overestimated, and an agitation for the general 

 sterilization of milk resulted. At one period a great quantity of the 

 cow's milk fed particularly to infants and children, but also to adults, 

 was sterilized by being boiled, often for a considerable time. While 

 this procedure yielded a milk of very excellent keeping qualities, it 

 was soon found to have its disadvantages in that it developed certain 

 features disagreeable to the taste, which after a time made it decidedly 

 distasteful and even repulsive to some people; but still more important 

 were the facts that it became less easily digestible and assimilable, 

 and that it, when fed exclusively to infants and very young children, 

 produced rickets and scurvy, with anemia and other metabolic and 

 developmental disturbances. The use of fully sterilized milk has today 

 been almost entirely abandoned in the feeding of infants, children, 

 convalescents, or invalids, and instead pasteurized milk is advocated 

 by many. 



