Transfer of melamine to cheese

Melamine can occasionally migrate into food from food-contact materials or occurs in food by direct contamination (fraudulent addition to illegally increase the crude protein level) or by indirect contamination (transfer from feed to milk, meat, eggs and derived products). The risk of migration from packaging material or plastic ware to food is remote because melamine is only hydrolysed in strong alkaline or acid solutions. The migration of melamine from polypropylene and polycarbonate plastic materials and melamine resin or from dairy product packages is negligible and should not be a health concern. Melamine may occur in milk either as a result of direct contamination or by indirect transmission from animals exposed to contaminated feed: the transfer efficiency of melamine from feed to milk was about 2%. During cheese making, most of the melamine content originally present in milk was transferred to the whey fraction (approximately 85%). On average, only 1.9% of melamine content in milk was found in cheese ripened 14 days. The melamine concentration only exceeded the EU limit of 2.5 mg kg-1 in cheese made from highly contaminated milk samples (>20 mg kg-1). Due to the partitioning ratios of melamine from milk to whey and cheese, cheese-making should not be a health concern for humans when cheese is made from milk produced by cows consuming less than 5 g day-1 of melamine.