Scientific Publications by FDA Staff

Food Addit Contam Part A 2015 Jan 8 [Epub ahead of print]

Investigation into the suitability of polystyrene as a functional barrier layer in coloured food contact materials.

Genualdi S, Addo Ntim S, Begley T

Functional barriers in food contact materials (FCMs) are used to prevent or reduce migration from inner layers in multilayer structures to food. The effectiveness of functional barrier layers was investigated in coloured polystyrene (PS) bowls due to their intended condition of use with hot liquids such as soups or chili. Migration experiments were performed over a 10 day period using FDA recommended food simulants (10% ethanol, 50% ethanol, corn oil, and Miglyol) along with several other food oils. At the end of the 10 days, solvent dyes had migrated from the polystyrene bowls at 12, 1, and 31,000 ng/cm2 into coconut oil, palm kernel oil, and Miglyol respectively and in coconut oil and Miglyol, the colour change was visible to the human eye. Scanning electron microscope (SEM) images revealed that the functional barrier was no longer intact for the bowls that were exposed to coconut oil, palm kernel oil, Miglyol, 10% ethanol, 50% ethanol, and goat's milk. Additional tests showed that 1-dodecanol, a lauryl alcohol derived from palm kernel oil and coconut oil was present in the polystyrene bowls at an average concentration of 11 mg/kg. This compound is likely to have been used as a dispersing agent for the solvent dye and aided the migration of the solvent dye from the polystyrene bowl into the food simulant. The solvent dye was not found in the 10% ethanol, 50% ethanol, and goat's milk food simulants above their respective limits of detection, which is likely to be due to its insolubility in aqueous solutions. A disrupted barrier layer is of concern because if there are unregulated materials in the inner layers of the laminate, they may migrate to food, and therefore, be considered unapproved food additives resulting in the food being deemed adulterated under the Federal Food Drug and Cosmetic Act.