25 September 1998

Storage mites pose threat

By Charles Abel

STORAGE mites in cereal-based foods could pose a serious health risk to consumers, prompting a call for stricter limits on contamination and better use of drying and cooling to keep grain mite free.

New research suggests the microscopic insects could cause asthma and potentially fatal allergic reactions when eaten by people already susceptible to such conditions.

CSL researcher Ken Wildey told last weeks annual congress of Environmental Health Officers in Harrogate he was surprised to find more than one in five cereal-based food products tested mites.

Some mites were still alive when extracted from tested food samples, which included baby food, breakfast cereal, flour and cakes. One pack of baby rusks contained 400 mites in 20g. "Although the study is still at an early stage, it appears some people almost certainly react to storage mites," Dr Wildey said.

Seven recent cases of life-threatening allergic shock involved patients who had eaten mites, although contamination levels were extremely high.

A precise limit on contamination, as in the US, France, Belgium and Italy, should be introduced as a matter of urgency, he said. "Although there is a strong case for retailed food to be mite-free, further work could identify an acceptable level below which there are no health effects."

Of the products tested flour was the most regularly infested, 28% of samples containing mites. Of all the samples tested, eleven would have been considered unfit for human consumption in the US.

"We cant say the contamination came from the grain, it could have arrived further up the food chain. But we know mites are present in all farm stores and problems have increased due to difficult harvests, longer storage periods and poorer control from organo-phosphate insecticides," said Dr Wildey.

The government review of OP insecticides, combined with growing mite resistance problems, mean more care is needed with store conditions, he advises. "Cool, dry conditions, with moistures below 14.5% are far more effective at controlling mites than pesticides." &#42

MITE MESSAGES

&#8226 20% of cereal-based food products infested.

&#8226 Trigger for asthma and potentially fatal allergic reactions.

&#8226 Precise limits required.

&#8226 Keep stores cool and dry.

Flour test negative

The National Association of British and Irish Millers says its own checks using CSLs new more sensitive test failed to find any mites in flour leaving its mills. "Problems may arise further up the food chain," says NABIMs Alex Waugh. "We know 15% of homes have storage mites in food storage areas, for example."It would also be interesting to know if the standards in other countries have made any difference to mite levels in foodstuffs. We need to know a lot more."