DKSICCATION 173 



cally, and are usually called prciu rratircfi. Among those 

 most commonly employed have been boric acid and bor- 

 ates, benzoic acid and its salts, salicylic acid, and formalin. 

 Boric acid is used in butter, especially in that made in New 

 Zealand and Australia to be shipped to the English mar- 

 kets. Benzoic acid is used in catsups and ciders, while 

 salicylic acid is contained in the canning powders that have 

 been widely sold in the past. Formalin has often been 

 used in milk. One part of formalin to ten thousand parts 

 of milk will have a marked inhibiting effect on bacterial 

 growth. The use of such chemicals in foods is prohibited 

 by law in most States, and by the national government in 

 its control of the interstate commerce in foods. The use 

 of benzoates is allowed in certain foods, but the amount 

 used must be stated on the label. 



As to the effect of such preservatives on health, different 

 views are held by various authorities. The prohibition of 

 their use is a wise one, since the foods in which they would 

 be used can be preserved by other means concerning which 

 there is no question as to their effect on the health of con- 

 sumers. 



Certain chemicals sometimes added to foods unite with 

 definite decomposition products, thus masking the effect of 

 the changes produced. If sodium bicarbonate is added to 

 milk, it combines with the lactic acid, and thus reduces the 

 acidity of the product. Sulphites are used with meats, 

 particularly chopped meats, to impart a bright red color 

 to the same and to neutralize the odors produced in putre- 

 factive changes. Potassium nitrate is used in corned beef. 

 Some of the nitrate is reduced to nitrite, which is an active 

 agent. It also imparts a bright red color to the meat. The 

 use of this latter substance is not regarded as dangerous. 

 Generally speaking, such chemicals can be used in suffi- 



