Fate of ochratoxin A in the processing of whole wheat grain during extrusion.

Ochratoxin A in cereal foods and some other products is controlled in the European Community by recent legislation with the objective of minimizing consumer exposure to this mycotoxin. Few studies have examined losses during processing. The stability of ochratoxin A during extrusion of contaminated wholemeal wheat flour was examined using pilot scale equipment. Factors examined were temperature, moisture content, screw speed and residence time. Ochratoxin A was partially stable with breakdown, increasing with temperature and moisture content. However, even under the harshest conditions likely to be used in commercial practice, maximum loss was no greater than 40%, with a residence time of about 40 s. The chemical properties of ochratoxin A suggest that breakdown might be affected by changes in pH and that further studies are necessary to investigate this possibility.