Relationship of mould count, ergosterol and ochratoxin A production.

The relationship between viable mould count, ergosterol content and ochratoxin A (OA) formation was studied at different inoculum concentrations of Aspergillus ochraceus NRRL 3174 and Penicillium verrucosum NRRL 3260 grown on sterile long-grain enriched white rice as the substrate. Ergosterol was determined by extraction, saponification and quantification using high performance thin layer chromatography (HPTLC) with UV detection. Ergosterol and ochratoxin A were detected after 3 days of incubation and reached their maximum at 7-10 days of incubation.

Occurrence of fumonisins and moniliformin in corn and corn-based food products of U.S. origin.

Food-grade corn and corn-based food products intended for human consumption were analyzed for the incidence and levels of fumonisin B1 (FB1), fumonisin B2 (FB2), moniliformin, and Fusarium molds. A total of 100 food-grade commercial corn samples were obtained from two corn processing companies at five different locations in the United States. Seventy-one percent of the samples contained FB1 with concentrations ranging from 43 to 1,642 microg/kg.

Fumonisin B1 production by Fusarium moniliforme and Fusarium proliferatum as affected by cycling temperatures.

The effects of temperatures cycling between 5 and 20 degrees C, 10 and 25 degrees C, and 15 and 30 degrees C on the production of fumonisin B1 (FB1) and ergosterol by Fusarium moniliforme and Fusarium proliferatum on rice was studied. Temperatures were cycled at 12-h intervals by manually moving cultures from one temperature to another. Constant temperature incubation at 25 degrees C and a low temperature stress were compared with the cycling temperature incubations.

High-performance liquid chromatographic method for the determination of moniliformin in corn.

A high-performance liquid chromatographic method using UV absorption was developed for determining moniliformin in corn. The toxin was extracted with water containing 1% tetrabutylammonium hydrogen sulfate (w/v). Paired moniliformin was partitioned into dichloromethane, which was evaporated to dryness at 50 degrees C.