Mycotoxin problems for cereal processors

Maximum limits for Fusarium mycotoxins, the poisonous compounds produced by fungi on grain under certain growing conditions, come into force this month with serious implications for cereal processors who could have trouble destroying them.

According to Dr Clare Hazel of RHM Technology, mycotoxins are very stable during normal processing and survive such treatment. So if they are present in the raw grain, they may occur in foods containing wheat flour, said Hazel. However, the chemical changes that take place during some processes, such as the extrusion of snacks, may destroy them, she added.

Hazel is project leader for a Department for Environment, Food and Rural Affairs Food Quality Link research project on the effects of processing on mycotoxin levels in foods. The three-year industry-academia project (FQS 64) includes United Biscuits and Kellogg.

Project co-ordinator Keith Scudamore of KAS Mycotoxins said the influence of around seven or eight different processes were being examined, including maize and wheat milling, bread making, as well as the manufacture of breakfast cereal, snacks and tortillas. Part of the project's remit was to explore ways of using contaminated product unfit for human consumption.

Under new EU rules, from July 1 the maximum limits for deoxynivalenol (DON) and zearalenone (ZEAR) Fusarium mycotoxins in unprocessed wheat are 1,250 and 100 parts per billion (ppbn) respectively. For flour the limits for DON and ZEAR are 750ppbn and 75ppbn respectively, while for finished products the limits are 500ppbn and 50ppbn. Even tighter controls have been introduced for infant food: 200ppbn for DON and 20ppbn for ZEAR.

Although DON and ZEAR in UK wheat does not present a major problem, said Scudamore, maize was more susceptible. There was also a problem where by-products such as bran - in which mycotoxins tend to concentrate - was used for animal food. Plans to introduce limits on HT2 and T2 mycotoxins in a year's time could present further problems, he added, especially with oats.

The Food Standards Agency has just issued advice to help farmers reduce the risk of wheat grain toxins for next season. It is also expected to publish a code of practice to reduce mycotoxins in cereals in November.

In separate work, researchers at Campden and Chorleywood Food Research Association have developed a rapid screening test for mycotoxins which produce results in just 10 minutes compared with several days for full lab-based mycotoxin tests.