Studies on Internal Corrosion of Cans (V)

Abstract

It is known that corrosion of inner tin-plate surface of can is greatly accelerated under (oxygen) atmosphere. The present study deals with the attitude of tin-dissolving in canned acid products after opening.Canned drinks and fruits were opened and allowed to stand either at room temperature or in a refrigerator. The products were then subjected to the analysis of tin after appropriate storage periods.(1) Tin-dissolving proceeds rapidly after opening of the canned products in uncoated cans regardless of the storage temperature. After storage for 3-6 hrs. tin content in orange drink, pineapple drink and mandarin orange in syrup was approximately 2 times than when opened. Tin content reached this level 24-48 hrs. after opening canned nectars, peaches or cherries in syrup in which corrosion is believed to proceed slower (Table 1 and 2).(2) When the canned foods are kept under the same (oxygen) atmosphere, the extent of the corrosion at the product level edge was found to be significantly different depending on the contents.(3) Caution must be paid on the storage after opening canned products contained in uncoated cans, especially those in uncoated smaller cans.(4) No appreciable increase of tin content is observed in canned products contained in enameled cans.