DIET AND NUTRITION 



Vitamin C is most abundant in fresh vegetable foods, 

 but the livers of well-fed animals contain a store of it. 

 Pasteurization of milk destroys practically all of it; and 

 as pasteurization of milk has increased in cities, infantile 

 scurvy has likewise increased. This is not a sound argument 

 against pasteurization, since it is now a general practice 

 to give infants some suitable fruit or vegetable juice which 

 will supply what has been destroyed in the heat treatment 

 of the milk. 



Citrous fruits and tomatoes are outstanding as rich 

 sources of this vitamin. Ordinary canned tomatoes are little 

 inferior to the fresh article, but bottled sterilized orange and 

 lemon juice have generally been found to be without value 

 in this respect. Raw potatoes, raw cabbage, lettuce, turnips, 

 etc., are excellent sources of the anti-scorbutic vitamin. 



The readiness with which vitamin C is destroyed on 

 heating milk and the absence of the vitamin from foods 

 cooked in the ordinary way led, a few years ago, to the 

 unwarranted assumption that canned fruits and vegetables 

 would be worthless as anti-scorbutic foods. That this was 

 an error was pointed out by Kohman and Eddy, who 

 showed that modern canning processes tend to preserve 

 much of the vitamin C content of the foods. The destruction 

 in ordinary cooking results from heating the food while it 

 still contains, dissolved in its juices, about 5 per cent by 

 volume of oxygen, and from continued heating in contact 

 with air. If this oxygen is removed by immersing the food 

 for a few hours in water before processing, the subsequent 

 heat treatment does not destroy the vitamin. Modern can- 

 ning methods involve subjecting the foods to diminished 

 pressure and to removal of the air by steam. This system 

 of cooking is responsible for the preservation of the anti- 

 scorbutic quality of most canned foods. 



[373] 



