Antifungal effect of acids and surface active compounds for post-harvest control of aspergillus parasiticus growth on hazelnut

Turkey is the world's leading hazelnut producer, and contributes nearly 70% to the total global hazelnut production. Aspergillus spp. are known to produce aflatoxins that can cause a variety of major concerns related to human health and economic losses. The objective of this study was to investigate alternative surface chemical treatment on shelled hazelnuts with an aim toward improving aflatoxic safety. Several surfactants and acids were screened for their antifungal activity against A. parasiticus strain 2929. Benzalkonium chloride, disodium-ethylenediaminetetraacetic acid and sodium hypochlorite were the most effective in combating A. parasiticus growth during storage of hazelnuts, and improved microbial attributes related to nut quality. The effects of chemical treatments on fungal cells and hazelnut were evaluated by Fourier transform infrared spectroscopy and scanning electron microscopy. The results demonstrate that direct spray exposure may provide an effective management process to suppress Aspergillus fungal growth and spore germination on hazelnuts. PRACTICAL APPLICATIONS: Aflatoxins are of the most carcinogenic residues found in diet, and prevention of food contamination is of great interest. Aflatoxin contamination is almost unavoidable after Aspergillus spp. grows on the food item; therefore, the infestation of food with aflatoxic fungus should primarily be prevented rather than the elimination of aflatoxins once produced. Based on the results presented in this study, surfactants can be applied as anti-fungal compounds to inhibit accumulation of A. parasiticus on shelled food items.