The occurrence of mites in cereal-based foods destined for human consumption and possible consequences of infestation

Seven categories of cereal-based food products purchased at food retail out lets in UK were examined for the presence of mites by analysing 20 g sample s using a flotation method. Mites were found in 21% of 571 samples, which w ere examined soon after purchase, and in 38% of 421 samples, derived from t he 571 samples which were examined after 6 weeks of storage in volunteers' homes. Most of the samples where mites were detected had fewer than five mi tes. However, a few samples contained more than 20 mites with a maximum of 428 mites detected in a single sample. Sixteen families, genera or species of mites were recovered. The most common species were Acarus siro, Tyrophag us putrescentiae, Lepidoglyphus destructor and Glycyphagus domesticus. The level of contamination was broadly similar for each of the seven categories of products examined. It is likely that infestation occurs at every stage of food processing and storage. This is the first study of its kind and the re is no reason to believe that results from similar studies carried out in other temperate countries would be markedly different. Increase in the per centage of contaminated samples following storage in a domestic situation s uggests that the domestic environment is an important factor in developing infestation. The implications of mite contamination on food quality and on human health are briefly discussed.