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Innovative management strategies for Aspergillus spp. and Penicillium spp. on nuts

Davide Spadaro: DISAFA and AGROINNOVA, University of Torino

<div>In postharvest, chestnuts and hazelnuts can be affected by species of <em>Penicillium, </em>agents of blue-green mould, and some species of <em>Aspergillus</em>, able to produce mycotoxins. Several strains of <em>Aspergillus</em> spp. and <em>Penicillium</em> spp. isolated from the chestnut field and production chain were characterized. <em>A. flavus</em> resulted the dominant <em>Aspergillus</em> species<em>.</em> Forty percent of the <em>Aspergillus</em> spp. strains produced AF<sub>S</sub> <em>in vivo, </em>while most strains were pathogenic on chestnut. A total of 20 species of <em>Penicillium</em> spp. were identified, including <em>P. crustosum,</em> <em>P. glabrum</em>, <em>P. bialowiezense</em>, <em>P. discolor</em> and <em>P. expansum</em>. Around 70% of <em>Penicillium</em> spp. isolated were pathogenic on chestnut, while 59% of the strains could produce at least one mycotoxin on chestnut. A new HPLC-MS/MS method was developed to detect twenty metabolites produced by <em>Penicillium</em> spp. on nuts. A LAMP assay was developed for <em>Aspergillus flavus</em>, while an antibody-immobilized microcantilever resonators was developed for mycotoxin detection. Drying conditions of chestnuts and hazelnuts is a critical point to reduce <em>Aspergillus</em> spp. and aflatoxin contamination. Monitoring, prevention and control are the strategies to manage <em>Aspergillus </em>spp. and <em>Penicillium</em> spp. on nuts. Besides these strategies, traditional static hot air roasting and infra-red rays roasting, together with cold atmospheric pressure plasma could be used for nut detoxification from aflatoxins.</div>