Bid to improve mite detection

29 June 2001

Bid to improve mite detection

WITH grain mites present in both stores and retail products and pesticide resistance increasing, scientists are striving to develop a way to spot the tiny pests early.

"We know that mites cause quality problems in UK grain. They contaminate it with body parts and excreta, alter its physical composition and can carry pathogens," says the CSLs John Chambers.

Mites have been found in 72% of farm stores, 81% of central stores and in 21% of retail cereal-based products, he notes. Eaten in large numbers they can give rise to various medical conditions including allergies.

A new way to detect them quickly and reliably is urgently needed, says Dr Chambers. Flotation and trap systems currently need laboratory analysis by experienced staff.

A two-year, HGCA-funded CSL project aims to produce a simple immuno-assay diagnostic kit for the most common storage mite species, Acarus siro, for use on site by farmers, storekeepers and millers.

"Work to date shows that simply rinsing mites provides enough antigen to be detectable, suggesting it will not be necessary to grind test grain samples," says Dr Chambers.

"In principle, anyone along the supply chain will be able to take a small sample, mix whole grains with a test solution and apply two or three drops of the extract to a cassette. A colour change will confirm mite presence."

Easy-to-use, rapid, low cost kits would allow more samples to be analysed than previously and give greater confidence that samples are representative of bulks, he says.

"We would recommend using them regularly for monitoring to increase awareness of potential problems and enable storekeepers to react promptly.

"We know storage mites are developing resistance to conventional pesticides. Our recommendation would focus on being aware of the problem, acting early and then limiting development by ensuring grain is dry and cool.

Dr Chambers is confident a working technique will be achieved by March next year, with a commercial kit possibly available 12-18 months later. &#42

MITESPOTTING

&#8226 Two-year HGCA project.

&#8226 £89,000 CSL research.

&#8226 Mites widespread.

&#8226 Rapid diagnostic kit aim.