MIGRATION OF MINERAL HYDROCARBONS INTO FOODS .6. PRESS LUBRICANTS USED IN FOOD AND BEVERAGE CANS

Unused food and beverage cans were supplied by manufacturers together with two typical samples of press lubricants used to facilitate stampi ng of can ends. The lubricants were based on mineral hydrocarbon fract ions. The cans were of aluminium two-piece construction (two sizes) an d tin-plate steel three-piece construction (two sizes) and of four rep resentative types. Gas chromatographic analysis was used to distinguis h the two press lubricants from one another by their n-alkane profiles . Analysis of solvent extracts of the cans indicated that one of the t wo press lubricants had been used in the manufacture of the three-piec e cans and the other lubricant for the two-piece cans. Residual levels of hydrocarbons were between 0.05 and 1.1 mg per can. Based on the ca pacity of the cans and assuming all the mineral hydrocarbon transferre d to the contents, maximum levels in foods and beverages could be betw een 0.1 and 4.4 mg/kg. A limited number of retail products were also a nalysed. For the 35 samples covering 18 retail brands of canned foods and beverages, press lubricants were considered to be present in 50% o f the products at levels ranging from 0.05 to 1.0 mg per can, equivale nt to 0.1 to 3.6 mg/kg of food. Additionally mineral oil of unknown or igin was detected in 10 of the retail products at levels of 0.1 to 4.7 mg/kg. Analysis of a sparkling apple juice packed in a glass bottle s howed mineral oil at 0.3 mg/kg compared with 0.7 mg/kg for the same ca nned product, indicating that although mineral oils may be used in can manufacture they may also be derived from other parts of the food pro cessing chain.