ADULTERATIONS OF MILK 225 



SO that permanent effects are realized only when these substances 

 are taken continuously. Tunnicliffe and Rosenheim go so far as 

 to assert that children increased in weight when the food contained 

 borax and boric acid. 



Boric acid in a concentration of 1 : 2000 is sufficient to preserve 

 milk in good condition for twenty-four hours. 



Salicylic add and benzoic acid are used only in rare instances. 

 Their effect on the system has not been definitely determined, as 

 opinions on the subject are divided. Hydrogen peroxid has been 

 recommended for preserving milk, and the "Buddeizing" of milk 

 as proposed by Budde has been shown to be very effective in 

 destroying micro-organisms. Buddeized milk is milk to which 

 hydrogen peroxid has been added at a temperature of 52° C. 

 The process has never become popular because there are several 

 serious drawbacks to the product. Excess of hydrogen peroxid 

 imparts a bitter taste to the milk and, furthermore, commercial 

 preparations of hydrogen peroxid deteriorate and, therefore, are 

 not reliable. They may also contain poisonous substances, such 

 as arsenic, barium salts, etc. 



The use of fluorids and potassium bichromate is so exceptional 

 that consideration of these substances as preservatives is hardly 

 profitable. Fluorids are poisonous, and potassium bichromate, 

 while not a violent poison, is by no means harmless. 



In summarizing the knowledge concerning the physiologic 

 efi'ect of preservatives in milk, it may be said that in minimal 

 quantities most of the preservatives used in milk are probably 

 not harmful when taken occasionally. When taken continuously 

 they may not be entirely safe, but since the quantity added is an 

 uncertain factor their use should be discouraged. Moreover, 

 there is no excuse for their use, since pasteurization furnishes the 

 means of removal of possible dangers in milk. Preservatives can 

 only be designed to disguise imperfect milk or altered milk, and 

 their presence is, therefore, not defensible in the light of present 

 knowledge. 



Detection of Formaldehyd. — 1. Hehner's Sulphuric Acid Test. 

 — Place 5 c.c. of the milk in a test-tube and pour about 3 c.c. of 

 commercial concentrated sulphuric acid slowly down the side of 

 the tube, so the liquids do not mix. At the junction of the liquids 

 a violet zone appears in the presence of formaldehyd. If pure 

 sulphuric acid is used a few crystals of ferrous sulphate should 

 be added to the acid, as iron is a necessary ingredient for this 

 test. 



When milk containing formaldehyd is tested by the Babcock 

 method for fat, a violet ring will form at the junction of the acid 

 and milk. 



