Field ecology, fungal sex and food contamination involving Aspergillus species

Several species within the genus Aspergillus are capable of producing a myriad of toxic secondary metabolites, with aflatoxin being of most concern. These fungi happen to colonize important agricultural commodities, thereby having the potential to contaminate our food with carcinogenic aflatoxins. Pre-harvest biocontrol of aflatoxins using non-aflatoxigenic A. flavus strains has been consistent thus far, but recent evidence of the capability of aflatoxigenic fungi to undergo both intra- and inter-specific sex necessitates a reevaluation of the biocontrol strategy. Sexual recombination at the field population scale could result in an increase in the proportion of adapted strains that are impervious to biocontrol due to aggressive growth as well as diverse toxin profiles. As well, global climate change could accelerate fungal sexuality and negatively impact food safety.