EARLY DETECTION OF AFLATOXIGENIC FUNGI ON MAIZE SEEDS

Fungi can grow on many food commodities. Some fungalspecies that belong to the genus Aspergillus are able to synthesiseand release in the environment carcinogenic toxins, such as aflatoxins.A. flavus and A. parasiticus, produce, under suitable conditions,aflatoxins, secondary metabolites which are toxic for humanand animals. Aflatoxigenic fungi are a real issue, especiallyfor the cereal industry. Several studies have tried non-destructive,spectral methods to detect fungal contamination and toxins oncereals. Many methods have been utilized to measure fungal contaminationand the presence of these toxins. The aim of this workis the early detection of aflatoxigenic fungi in cereals, such maize,the discrimination between healthy and diseased cereals and thedetermination of the extent of damage caused by the use of hyperspectralimaging and DNA-based methods. A hyperspectralimaging system, ImSpectorTM, V10 and two aflatoxigenicspecies, A. parasiticus, and A. flavus were used in this work. Bothfungi were inoculated on maize and were imaged from 24 h to 7days of growth. Changes in reflectance of maize were observedduring fungal growth. This approach could be a rapid methodfor detecting the aflatoxigenic fungi on cereals. New methods developedin recent years include DNA-based analytical methods(PCR) for detection of fungi. We present a molecular method,based on PCR amplification of the omt gene, which encodes theenzyme necessary for the last step of aflatoxin biosynthesis.Specificity was assayed with DNA extracted from 7 different fungalspecies. Amplification was obtained only with DNA fromaflatoxigenic A. flavus and A. parasiticus.