HEALTH AND SAFETY CONSIDERATIONS IN PRINTING

98test conditions, by use of a mathematical model. (Silva, Cruz, Garcı´a, Franz,&Losada 2007)The results showed that migration increased with fat content and storagetemperature. Analysis of migration data corresponding to minced pork meatcontaining different amounts of fat, stored for 10 days at 25 0 C, revealed an excellentrelationship between migration level and fat content. This behaviour was also foundfor other types of meat products (chicken and pork neck).A simplifying mathematicalmodel 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 porkmeat contact, the effective diffusion coefficients derived from mathematicalmodelling were ten times higher for storage at 25 0 C (1.88 x 10 -9 cm 2 s -1 ) than forstorage at 5 0 C (1.2x 10 -10 cm 2 s -1 ). (Silva et. al., 2007)Migration of low molecular weight substances into foodstuffs is a subject ofincreasing interest and an important aspect of food packaging because of the possiblehazardous effects on human health. The migration of a model substance(diphenylbutadiene) from low-density polyethylene (LDPE) was studied infoodstuffs with high fat contents: chocolate, chocolate spread and margarines(containing 61% and 80% fat). A simplifying mathematical model based on Fick’sdiffusion equation for mass transport processes from plastics was used to deriveeffective diffusion coefficients which take also kinetic effects in the foods intoaccount and to determine partition coefficients between plastic and food. With thismodel migration levels obtainable under other storage conditions can be predicted.The effective diffusion coefficients for both margarines stored at 5 0 C (3.0–4.2 x10 -10cm 2 s -1 ) and at 25 0 C (3.7 - 5,1 10 -9 cm 2 s -1 ) were similar to each other, lower than forchocolate spread stored at 5 0 C (9.1x 10 -10 cm 2 s -1 ) and higher than the diffusioncoefficient for chocolate stored at 25 0 C (2.9x 10 -10 cm 2 s -1 ). Good agreement wasfound between the experimental and the estimated data, allowing validation of thismodel for predicting diffusion processes in foodstuffs with high fat contents. (Silva,et al, 2007).