About the significance of the fungal genus Alternaria for the food sector: plant pathogens and mycotoxins

The fungal infestation of agricultural crops worldwide leads to considerable economic losses every year. Moreover, certain major plant pathogens like Alternaria species produce harmful secondary metabolites, so-called mycotoxins, which may result in food contamination and therefore a potential health risk for consumers. Data on the occurrence and the toxicological potential of the “emerging” Alternaria toxins are still scarce, which limits comprehensive risk assessments. Here, we present a summary of current Alternaria research focusing on the development of innovative analytical tools to determine contamination patterns in various food products and the investigations of metabolic defense strategies in plants and mammals (biotransformation). By the application of sophisticated LC-MS-based multi-toxin quantitation methods, barely studied toxins and even biologically modified toxins were revealed to contribute considerable concentrations to the overall exposure. Furthermore, in vivo studies gave intriguing first insights in bioavailability, metabolism, and excretion rates of Alternaria toxins in rats. These valuable data set demonstrates the necessity for further studies to approach the question, whether legal regulations of Alternaria toxins would be appropriate to continuously ensure and increase food safety.