MIGRATION OF MINERAL HYDROCARBONS INTO FOODS .3. CHEESE COATINGS AND TEMPORARY CASINGS FOR SKINLESS SAUSAGES

Levels of mineral hydrocarbons which have migrated from wax coatings into cheese have been determined for 20 retail samples using a gas chromatographic procedure. Contamination was limited to the outermost 2 mm of cheese in direct contact with the wax where levels of hydrocarbons were found to range from 10 to 150 mg/kg. On a whole cheese weight basis these amounted to < 1 to 27 mg/kg (< 0.2 to 3 mg/dm2 contact area). Components attributed to hydrocarbons in cheese samples remote from the waxed surface (background levels) were typically 3-5 mg/kg. Background levels were subtracted from the results for surface samples to obtain migration values. There was evidence that the surface contamination of cheese with mineral hydrocarbons occurred by a combination of diffusion into the cheese and adhesion of wax components onto its surface. Mineral hydrocarbons are used in the manufacture of the temporary casings used to mould skinless sausages. Of 33 retail products examined, including skinless sausages, hot-dog sausages and frankfurters, 25 (75%) contained levels of mineral hydrocarbons from 10 to 105 mg/kg. These hydrocarbons were shown to be present principally at the surface of the food and so could be attributed to migration. Nine other minced meat products were examined for comparison, including minced beef, pate, sausage meat and sausages with skins. Levels of mineral oil in these products were insignificant by comparison, typically below the limit of detection of ca 4 mg/kg, indicating insignificant adventitious contamination from routes other than migration.