Mycotoxins in ingredients of animal feeding stuffs: II. Determination of mycotoxins in maize and maize products.

Analytical methods have been developed for the reliable detection and estimation of 22 mycotoxins in maize gluten and other maize products used in the animal feed industry. The mycotoxins are aflatoxins B1, B2, G1 and G2, ochratoxins A and B, citrinin, cyclopiazonic acid, zearalenone, sterigmatocystin, deoxynivalenol, nivalenol together with seven related trichothecene mycotoxins, fumonisins B1 and B2 and moniliformin. For most of the mycotoxins, recoveries obtained were 60% or greater and reproducibility data were better than +/- 40%. In general, the analysis of maize gluten proved more difficult than for other maize products. In total 40 samples of maize gluten, and 27 samples of other maize products were examined. Aflatoxins were not found above the reporting limit (1-5 micrograms/kg) in any sample while ochratoxin A was detected in only two samples of maize gluten at 2 micrograms/kg. No sterigmatocystin or cyclopiazonic acid were detected although the limits of detection for these toxins were poor. Twenty percent of maize gluten samples contained zearalenone at up to 500 micrograms/kg while all other maize products also contained this mycotoxin. Highest levels occurred in screenings and meal while the lowest amounts were in flaked maize and germ. Many samples contained a multi-toxin mixture of trichothecenes, fumonisins and moniliformin. The most highly contaminated samples of maize screenings and maize meal contained a mixture of zearalenone, deoxynivalenol, nivalenol, fumonisin B1 and B2, moniliformin, each in mg/kg amounts and lower amounts of other trichothecenes such as 15-acetoxy deoxynivalenol, HT-2 toxin and T-2 toxin. Fumonisins occurred in all except two gluten samples and occurred up to a level of 32 mg/kg in maize screenings, 13 mg/kg in maize meal and 8 mg/kg in maize germ.