Approach to stochastic modelling of consumer exposure for any substance from canned foods using simulant migration data

A two-dimensional probabilistic model was constructed to estimate the short-term dietary exposure of UK consumers to any generalized migrant from coated light metal food packaging. Using three UK National Dietary and Nutrition Surveys ( NDNS) comprising 4-7-day dietary surveys for different age and gender groups, actual body weights and survey years, a sample representative of the dietary consumption of the UK population was obtained comprising around 4200 food items. Interrogation of the raw data showed that the per capita consumption of food and beverage for an adult was 2.9 kg per person day(-1), which is comparable with the US FDA value of 3.0 kg. The packaging type of each food item was assigned from the survey descriptions or by sampling from distributions based upon market share information and expert judgement. Each food item was assigned to the relevant food simulant: A ( aqueous), B ( acidic) or D ( fatty), so that simulant migration data could be used. The exposure model was used to evaluate exposure for a given level of migration and, conversely, the level of migration that could be tolerated whilst keeping within a target threshold exposure level. As examples, migration at 10 mu g dm(-2) into fatty foods only resulted in an exposure ranging from 0.06 to 0.22 mg kg(-1) body ( actual) weight day(-1) depending on the scenario. The model revealed that if migration from metal coatings was only into fatty foods, migration in the range 1.83 - 4.95 mu g dm(2) ( 97.5th percentile, depending on the scenario) would give an exposure of less than 1.5 mg per person day(-1). This is a toxicological threshold limit used in the USA. If migration into simulants A and B is also considered to be at the same level as that for simulant D, then the level of migration for the threshold to be reached is, not surprisingly, lower ( 0.64 - 0.87 mu g dm(-2)) than that if migration were only into fatty foods. In this case, clearly the main contributors to the exposure were foodstuffs represented by simulants A and B because of their importance in the diet. These estimates are based on 4- or 7-day food diaries and chronic exposure over the long-term would be expected to be lower.