Debaryomyces hansenii as potential biocontrol agent against Aspergillus westerdijkiae and its ochratoxin A production on cheese-like medium

effects on human and animal health. As OTA represents a relevant food safety concern and cheese has been reported as a potential source of consumer exposure, effective mitigation strategies are needed. Debaryomyces hansenii is a yeast isolated from multiple environments, with high biotechnological potential, particularly in the food industry. It is commonly associated with cheese ripening and has previously shown antagonistic activity against ochratoxigenic fungi in fermented foods, but there is currently no evidence of such activity against A. westerdijkiae on ripened cheese. Therefore, this study aimed to investigate the ability of D. hansenii ITEM 19968 to inhibit the growth and OTA production of 13 A. westerdijkiae strains on a cheese-like medium. The yeast was incorporated into the culture medium and fungal growth and OTA production were compared with untreated controls after incubation for up to 20 days. Obtained results indicated that presence of D. hansenii reduced fungal growth after 10 days inoculation onwards, with inhibition values ranging between 17% and 31% after 20 days. Furthermore, OTA production was reduced in all OTA-producing strains by 63% to 100%, with complete inhibition observed in seven strains. The marked reduction in OTA accumulation, which exceeded the reduction in fungal growth, suggests that D. hansenii may affect both fungal development and mycotoxin biosynthesis. These findings highlight that Debaryomyces hansenii is a promising candidate for use as biocontrol agent during cheese ripening process, to reduce OTA contamination and improving food safety.