Risk assessment and management of sulphite in minced meat

Summary

​Foods and beverages containing sulphur dioxide and sulphites can trigger asthmatic reactions in some people. The addition of sulphur dioxide and sulphites to a range of specified foods is permitted in Australia, but labelling is mandatory. The addition of sulphites to raw meat, including mincemeat is illegal. In Victoria 2.74% of samples of mincemeat from retail butchers shops contained SO2 and sulphites, and levels in illegally contaminated mincemeat in NSW were in the range 28 – 1539 ppm (mean 350 ppm). People with asthma and sensitivity to SO2 and sulphites are sometimes exposed to these additives in mincemeat without their knowledge. It was estimated that 50,313,000 servings of mincemeat are purchased in retail butchers shops per annum in Victoria. An exposure assessment estimated that children with asthma and sensitivity to SO2 and sulphites consume 1630 servings of mincemeat containing 50 mg or more of SO2/sulphites per annum in Victoria, and adults with asthma and sensitivity to SO2 and sulphites consume 800 servings containing 50 mg or more of SO2/sulphites per annum in Victoria.

Thus it would be expected that an asthmatic child or adult with sensitivity to SO2/sulphites would consume a serving of mincemeat with 50 mg or more SO2/sulphites approximately once every 23 years. It has been proposed that SO2 is the chemical form which triggers asthmatic reactions. Decreasing pH increases the release of SO2 from sulphites as free ions and reversibly bound forms. While 50 mg of sodium metabisulphite in citric acid solution produced asthmatic reactions in 65% of children with chronic asthma and 66 mg of sodium metabisulphite in apple juice produced asthmatic reactions in 22% of children with chronic asthma, the proportions of asthmatic reactions when the same amount of sulphites are present in cooked mincemeat may be much lower because of the higher pH of meat, and the chemical characteristics of meat.

Despite exposure through illegal additions to mincemeat no reports were found of severe asthmatic reactions having occurred as a result of the consumption of mince meat to which SO2 and sulphites had been added. This may be due to a lack of reporting, use of medication preventing/relieving reactions or because the pH and chemical characteristics of mincemeat minimises the release of SO2, the chemical form that may trigger asthmatic reactions. A clearer characterisation of the likelihood of reactions given the estimated level of exposure requires data from a double blind challenge study of consumption of cooked mincemeat with added sulphites, by asthmatic people with SO2/sulphite sensitivity.