The characteristics and performance of several non-PVC stretch films were compared to those of plasticized PVC. Initially the main polymer components Of the film were identified by infrared spectrometry and differential scanning calorimetry. The differences between films in mechanical properties, such as puncture resistance and tensile strength, varied about a factor of two, while the differences in elongation at break were considerably higher. Plasticized PVC showed properties somewhere in the middle. The water vapour transmission was highest for PVC, while its permeability to oxygen was the lowest. The potential for overall migration was assessed by substitute testing, using 95% ethanol and isooctane as test media, and the migration from PVC was found to be the highest. However, after use of the appropriate reduction factor of four, as allowed for fresh meat, the PVC film also proved to conform to legislation. The potential for specific migration was investigated by solvent extraction followed by gas chromatography. Twenty-four components were identified, of which 11 could be compared to relevant migration limits based on evaluations of the EU Scientific Committee for Food. The release of solvents was estimated by direct thermal desorption at 100degreesC. Four films of different composition were used in a storage experiment with fresh beef. The meat quality was followed by measurements of colour, microbiological quality (total colony forming units and lactic acid bacteria) and lipid oxidation (thiobarbituric acid reactive substances) through a prolonged shelf-life test. No differences in meat quality during normal shelf-life were seen as a function of the film used.
Packaging Technology and Science, 2004, Vol 17, Issue 2, p. 53-66