CHEESE 109 



Poisonous Metals. — ^Lead chromate has been 

 found in the rind of cheese, and finely divided 

 lead in a number of Canadian cheeses. In 

 England zinc sulfate has been employed under 

 the name of cheese spice to prevent the heading 

 and cracking. Arsenic has also been found; it 

 may be detected by Reinsch's test. Lead, zinc, 

 and chromium may be detected by ashing a 

 portion of the sample in a porcelain crucible and 

 applying the usual tests. 



