The amounts of substances migrating from plastics into foodstuffs with high fat contents are in most cases higher than in foodstuffs with water contents. This increase in migration commonly is due to the higher solubility of the migrating organic compounds in fat compared to water. The increase in migration is not necessarily due to an increase in the substance's diffusion coefficient due to interactions between the fat and the plastic as is often assumed. Ethanol is a good simulant for fatty foods because it has little interaction with many plastics, e.g. polyolefins, migrants are readily soluble in it, and because it is easy to work with analytically. The utilizable limits of ethanol and ethanol/water mixtures as food simulants are developed from the physical background of diffusion. The use of ethanol and ethanol/water mixtures is supported by published experimental migration results.

Diffusion↗

PubMedDate not supplied

Testing and evaluation of recycled plastics for food packaging use--possible migration through a functional barrier.

A coextruded three-layered polypropylene (PP) cup with recycled PP material (R-PP) in the middle layer was investigated with respect to its possible use for a specific food packaging application. From the results of this investigation a general approach to testing and evaluating the use of recycled plastic materials in food packaging is presented. The method which focuses on the direct comparison of the R-PP containing cup with a food grade PP cup manufactured from virgin material involves essentially three investigation levels: 1, compositional analysis of the raw materials, i.e. PP and R-PP granules; 2, compositional analysis of the PP and R-PP cup materials and 3, migration testing of both types of cups applying practical as well as more severe test conditions. The aim of this approach is to test the PP food contact layer for its functional barrier behaviour. One key step is the estimation of migration under practice-like test conditions in concentrations below the analytical detection limits. This can only be achieved by selecting appropriate R-PP specific guide compounds whose migration can be monitored under more severe conditions than occur in practice. From the results of this investigation general conclusions on functional barrier testing are drawn.

Alkanes↗

PubMedDate not supplied

Presentation and experimental verification of a physico-mathematical model describing the migration across functional barrier layers into foodstuffs.

For several years there has been an ongoing controversial scientific discussion about the so-called functional barrier concept which, although mostly connected with the re-use of recycled plastics for food packaging, has general relevance and is principally applicable to any type of multilayer structure. Concerning the definition of the efficiency of a functional barrier there exists different understandings, ranging from the absolute physical barrier requirement over the acceptance of toxicologically insignificant migration to a completely lag time-related definition. The starting point of this work was the fact that functional barriers are in most cases already in-situ-contaminated due to the thermally extreme coextrusion conditions of the manufacturing process. As a consequence, middle layer contaminants may already have penetrated the functional barrier of a food package and may provide direct contact with the foodstuff at the time when the package is filled. Nevertheless, depending on the individual food package parameters, the remaining functional barrier efficiency can still prevent inadmissible migration. To meet this real-life situation and to describe the underlying migration process a theoretical migration model was developed and experimentally verified in this work using artificially-contaminated multilayer HIPS sheets with different functional barrier thicknesses. An important result of this study was the finding that compared with the interdiffusion between the package's layers in situ during their formation in the coextrusion process, the interdiffusion at ambient temperature until the filling time point of the package is able to be neglected.

Chlorobenzenes↗

PubMedDate not supplied

Cord blood T-cell determination: a further useful parameter for atopy screening of the newborn?

In a prospective study, the total CB IgE and T-cell subpopulations in cord blood of 200 newborn children were determined by means of monoclonal antibodies (CD3, CD4, and CD8). There is no correlation between raised cord blood IgE and reduced T-cell ratio in the cord blood or with a positive family history. In a follow-up study carried out at the age of 12 to 14 months, 21% of atopic children had a positive family history and, simultaneously, a reduced total cord blood T-cell rate (CD3). Only 3% of nonatopic children had a positive family history and a reduced cord blood CD3 ratio. Statistically speaking, this distinction is significant (p less than 0.01).

Female↗

PubMedDate not supplied

[Microtrauma and cartilage injury].

In addition to macrotraumas resulting from single and heavy impact, recurrent microtraumas are probably frequently the cause of cartilage damage. The risk of a microtraumatic cartilage damage exists especially in activities involving a high load frequency. Epidemiological studies and dynamometric measurements in race events support this assumption. Based on experimental investigations it is shown how the different components of the articular system-cartilage, synovial membrane and subchondral bone react to microtraumatic stress. In the elimination of microtraumatically induced joint damage special emphasis should be placed on prophylaxis.

Animals↗