Contribution of packaging materials to MOSH and POSH contamination of milk powder products during storage

Mineral oil hydrocarbons (MOH) in milk powders, particularly in infant formulas, have been and continue to be a major concern to the public worldwide. These contaminants are likely derived from environmental pollution, manufacturing process and packaging materials. In this study, 23 Chinese commercial milk powder products packaged in four types of materials, i.e. metal cans, paper containers, paperboard boxes with internal bags, and aluminium foil-plastic bags, were collected and stored for 1 year. The total and surface MOH in these samples were detected and compared before and after storage to understand the MOH migration during storage, despite no mineral oil saturated hydrocarbons (MOAH) were detected. The contents of mineral oil saturated hydrocarbons (MOSH) and polyolefin oligomeric saturated hydrocarbons (POSH) in metal cans were the least among the four packages and changed little during storage, which suggested that little MOH migration occurred in metal material. Despite all the food contact materials in the other three packagings were the aluminium foil-plastic composite, the similar low migration occurred in the aluminium foil-plastic bags and internally contained composite bag(s) in paperboard boxes. However, both total and surface MOSH and POSH easily migrated from the paper-plastic-aluminium composite of paper containers during storage. These findings are helpful for the selection of packaging materials in manufacturing milk powder products or other foods.