COPPER IN CANNED VEGETABLES. 



1017 



vessels would secure a deeper and more attractive green appearance for 

 the cooked product. It did not take the observing cook long to discover 

 that this improvement in appearance was due to the copper or zinc 

 present in the copper or brass vessels. The same effect was found to 

 be produced when these vegetables were cooked in ordinary vessels 

 with the use of small quantities of copper or zinc salts. Upon the whole, 

 copper salts were found more convenient for this purpose, and hence at 

 the present day an immense industry has grown up in the greening of 

 canned vegetables by the use of copper and zinc, especially of the former. 

 By consulting the analytical data which follow, it will be found that a 

 large part of such canned goods exposed for sale in this country has 

 been greened by the addition of copper, and in some cases of zinc. For 

 instance, the amount of copper found in peas of French origin was uni- 

 formly much greater than that found in American canned peas. Of 

 forty-three samples of American canned peas examined 32.56 per cent 

 were found to contain no copper, while 67.44 per cent were colored with 

 copper. Of thirty-six samples of French peas all were colored with 

 copper, except one, which was colored with zinc. In regard to the quan- 

 tity of copper found the folio wing comparison will be of interest: 



The literature on this subject, it will be found, has been carefully 

 collated in the pages which follow, and, as in the case of added pre- 

 servatives, it is difficult to come to a definite conclusion in the matter. 

 Almost the same statements may be made in regard to the use of 

 greening materials as have been made in respect of added preserva- 

 tives. 



The occasional use of a small quantity of a copper or zinc salt, it 

 must be allowed, can be practiced without practical injury to health. 

 On the other hand, the continual and regular consumption of even the 

 small quantities of these materials present in canned vegetables must 

 be regarded as at least prejudicial to health. Therefore it is con- 

 cluded that the public health will be sufficiently conserved provided 

 each can of vegetables which has been greened artificially in this way 

 shall bear plainly marked upon the label the nature of the greening 

 material and the amount thereof employed. The responsibility of the 

 use of these vegetables will then be thrown upon the consumer and he 

 can exercise his own judgment in regard to the matter. 



