Plastic materials, made mostly from petroleum based chemicals, are often indicted for their potential to harm human health when used for packing foods. When a food is packed in a plastic container, be it a film pouch or a rigid container, there is a tendency for the food to leach out some of the constituents used in the manufacture of the container into the contents and such migration is influenced by many factors including the type of container used, temperature, pH of the food, composition of the food, duration of contact, storage environment etc. To allay such fears, a scientific study in Australia and New Zealand was undertaken with government blessings and the findings provide interested reading.
"Following the analyses, the FSANZ team declared: "There were no detections of phthalates, PCFs, semicarbazide, acrylonitrile and vinyl chloride in any of the foods analysed in this survey." However, ESBO, produced by epoxidation of soybean oil and used in a range of plastics most often as a plasticiser, was the only one of the potential chemicals of concern detected in the exercise. It is also commonly used in PVC sealing closures (gaskets) of glass jars to form an airtight seal to prevent microbiological contamination of foods . PVC, in the form of films and gaskets, can contain up to 30 per cent of the substance. The chemical was found in three foods packaged in glass jars at concentrations ranging from 4.2 to 10 mg/kg. The highest levels were discovered in olive brine, followed by savoury pasta sauce and infant dinners".
How far the study really represents the whole spectrum of the food industry is not clear. Also the sample size and the varieties of packaging material studies do not appear to be adequate to come to any sweeping conclusion as done by the group involved in this study. There universally accepted methods to study migration behavior of plastics and food processors are expected to confirm when buying the packaging materials that the container suppliers vouch safe regarding the food grade specifications of the same. Another uncertainty pertains to the impact of cumulative ingestion of substances migrated into foods packed in various plastics on human health. One should not forget the recent food tainting episode in Taiwan caused by the plasticizer DEHP which is used in PVC up to 40%. Considering all these factors consumer may be justified in asking for safer and sustainable alternatives to fossil fuel based packing modes for foods.