Antifungal and antiochratoxigenic properties of chemical preservatives of bread

Abstract

The objective of this work was to study the efficiency of preservatives on growth and ochratoxin a (ota) production by Aspergillus niger 13 d at pH values often found in bakery products. the fungal growth inhibition was concentration and pH dependent. differences between calcium propionate (Cp) and potassium sorbate (ks) were found, observing that ks was less effective than Cp. no fungal growth was observed with 0.4% (w/w) of Cp at pH 6.0, while that the maximum concentration of ks (0.2%, w/w) was not able to inhibit 100% of fungal growth independentlyof pH evaluated. This study also demonstrates the influence of preservatives on ota production. ota was not detected when the growth was 100% inhibited, i.e., at pH 6.0 and 0.4% (w/w) of Cp. the concentration of Cp could be reduced at 0.3% (w/w) when the pH was lowered to 5.5 without risk of contamination with ota. In presence of ks, a moderate depletion of ota production was observed, however, the maximum concentration (0.2%, w/w) did not completely inhibit ota production. in addition, no stimulating effects on growth or ota levels were observed in any condition assayed. These “in vitro” studies must be corroborated by “in situ” conditions in bakery products and other Aspergillus fungus.