Fusarium mycotoxins in the food chain: maize-based snack foods

The fate of deoxynivalenol (DON), zearalenone (ZEA) and fumonisins B-1 (FB1) and B-2 (FB2) were examined in three representative snack food production methods. Assessing results on an 'as is' basis so as to compare results with EC legislation showed DON to be the most stable mycotoxin during the manufacture with mean levels in each finished products >68% of the levels in the starting ingredients. The concentrations of ZEA in the snack food ingredients during this study were very low but did allow limited studies that showed a mean 52% reduction during the manufacture of one snack product, but little reduction when producing a tortilla chip. In contrast, fumonisins were mostly lost (>90%) in two out of the three processes. However in a tortilla chip prepared from maize flour by extrusion, heating and frying, the amount of FB1 + FB2 remaining in the retail product was reduced on average by 59% which is similar to the 60% difference in the statutory levels for flour (products <500 micron) or 50% difference for grits (products >500 micron) and retail snack products. Thus the use of maize containing fumonisins in maize flour at levels just meeting legal limits would present some risk that a proportion of retail products might fail to meet legislation when the run to run variability is considered. The buyer/processor should thus avoid ingredients containing mycotoxin levels close to legislatory limits for use in processes where reduction at successive stages in manufacture are close to or less than those in the legislation. It is suggested that this study provides a useful indication of these. In commercial operation, there is a reluctance to specify raw materials at anything but the finishing product levels with implications for availability and cost.