A. Sanches Silva

Kinetic migration studies from packaging films into meat products

One of the main concerns regarding safety of food packaging is the possible migration of chemical substances (monomers and other starting substances, additives, residues) from food contact materials into foods. To evaluate the effect of the fat content and of the temperature of storage on the migration from plastics packaging films into meat products as an important class of foodstuffs, the kinetic mass transport of a model migrant (diphenylbutadiene) from low density polyethylene (LDPE) film in contact with different meat products was investigated. From the data, the diffusion coefficients were calculated for the applied test conditions, by use of a mathematical model. The results showed that migration increased with fat content and storage temperature. Analysis of migration data corresponding to minced pork meat containing different amounts of fat, stored for 10 days at 25°C, revealed an excellent relationship between migration level and fat content. This behaviour was also found for other types of meat products (chicken and pork neck). A simplifying mathematical model was applied to derive effective diffusion coefficients in the polymer which, however, do take kinetic effects in the meat also into account. In the case of pork meat contact, the effective diffusion coefficients derived from mathematical modelling were ten times higher for storage at 25°C (1.88×10(-9)cm(2)s(-1)) than for storage at 5°C (1.2×10(-10)cm(2)s(-1)).

Migration and diffusion of diphenylbutadiene from packages into foods.

Monitoring of exposure to chemicals from food contact materials is a subject of increasing importance. The concentration of the chemicals and their migration levels, as well as food consumption and packaging usage data, are required to enable calculation of the degree of such exposure. The present study investigated the migration kinetics of diphenylbutadiene (DPBD) from packages into flour, rice, honey, milk powder and toast. Migration was not always negligible, except in honey and skimmed milk powder. Experiments carried out with starch alone enabled us to conclude that diffusion of migrants occurred through starch and fat. Key diffusion parameters were determined (diffusion coefficient and partition coefficient) based on Ficks second equation. The following diffusion coefficients were obtained at 25 degrees C: 2.7 x 10(-10), 3.4 x 10(-11), 3.2 x 10(-10), 8.4 x 10(-11), 8.1 x 10(-11) cm(2) s(-1), for wheat flour, rice, milk powder and toast, with 4 and 21% fat, respectively. A very good fit between experimental and predicted data was achieved. The data obtained in the present study confirm the validity of the mathematical model for predicting migration from Food Contact Materials (FCM) into foods.