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Australian canned foods - safe from chemical contaminants

The potential for chemical contaminants to migrate from packaging materials into foods has raised concern as a potential food safety hazard. Steel cans require protective lacquers for some classes of foods, such as those containing high levels of acid. These lacquers prevent can corrosion and the development of unsightly staining of food. Since the 1990s most of these protective lacquers have been based on epoxy resins. Bisphenol A (BPA), its di-glycidyl ether (BADGE) and BADGE's related compounds have been shown to migrate from epoxy can linings into food.

BADGE is a compound that has the potential to act as a human endocrine modulator if ingested. Endocrine modulators are chemicals that interfere with the endocrine system which is responsible for hormone secretion. Although many industrial compounds are suspected of affecting endocrine function in humans, no studies have definitively linked this to the levels found in food. However, public concern about exposure to these compounds has not abated. The key issue is their concentration in our diet; therefore regulatory authorities specify limits for their tolerable daily intake (TDI). The TDI is an estimate of the amount of a substance that can be consumed daily over a lifetime without appreciable risk. Australian canned food manufacturers who export their products face severe costs in recall of stock and loss of market access if specified TDI limits are exceeded. In January 2007, the European Food Safety Authority set a new TDI for BPA of 0.05 milligram per kilogram of body weight (http://www.efsa.europa.eu/en/science/afc/afc_opinions/bisphenol_a.html). This limit was decided upon after extensive testing and evaluation of the toxicology of BPA.

Australian canned food manufacturers have been pro-active in ensuring that migration of contaminants from packaging into foods is not a risk to consumers. Research to determine the factors affecting contaminant migration from Australian cans into food was conducted by Food Science Australia in 2002, with assistance from representatives of the packaging and lacquer industries. To determine if any contaminants found in the canned food were present prior to canning (for example, from processing water), samples taken before and after canning were analysed. Sixteen different food types were analysed including vegetables, meat, cheese, fish and desserts. The study also aimed to determine the effects of differing storage conditions on the level of contaminant migration into food. Samples were analysed over a six month period under temperate and tropical conditions.

For all samples tested, levels of BADGE or its related compounds were below the level set by the European Commission which is one milligram BADGE per kilogram of food (http://www.eu.nl/food/fs/sc/scf/out28_en.pdf). Although contaminant levels detected were too low to allow for conclusive comparisons, it appeared that storage times and temperatures did not adversely affect contaminant migration from can linings.

The study showed that the current manufacturing practices for Australian canned foods do not represent a health hazard for Australian or overseas consumers.