Occurrence of aflatoxins in wheat flour specified for sangak bread and its reduction through fermentation and baking

Abstract

This study was conducted as a screening survey to determine the occurrence of total aflatoxins (TAF) levels in sangak flour samples provided from flour factories and bakeries and to assess the effect of commercial fermentation and baking practices on the most contaminated flour samples. In addition, the effect of fermentation by yeast (Saccharomyces cerevisiae) and a mixture of yeast and a lactobacillus strain (Lactobacillus plantarum LA7) in reducing aflatoxins in prepared sangak breads were compared. The competitive enzyme-linked immunosorbent assay method was employed to determine toxin levels in the samples. With contamination levels ranging from 6.68 to 34.47 ng/g, the majority of the tested samples were not considered safe. Mean aflatoxin contamination of examined samples was 18.06 ng/g. Considering the limits for TAF in wheat flour set by ISIRI and EC (15 ng/g), 56.7 of the samples were unacceptable. No significant correlation was found between ash content and TAF levels (P>0.05). A significant decrease in aflatoxin levels was seen during sangak bread manufacturing (P<0.01). Dough fermentation by yeast and the mixture of yeast and L. plantarum LA7 resulted in 33.7 and 40.7 decrease in aflatoxin levels of the contaminated dough, respectively. On average, the sangak bread made with the most contaminated flours contained 11.1 ng/g of TAF, which was above the established maximum residual level in Iran and European countries.