Occurrence of toxigenic fungi and mycotoxins in pig feeds: potential implications for workers' exposure

: The objective of the study was to assess the potential exposure of pig farmers to toxigenic fungi and mycotoxins by investigating their presence in feeds to understand whether these matrices may represent a source of release into the environment and pose an occupational health risk. Nine feed samples were collected from several intensive farms located in Southern Italy and analyzed through a multi-methodological approach. A total of 35 molds were isolated and A. flavus turned out to be the most frequently species, representing nearly 46% (16/35), followed by A. niger and A. candidus, each at 11.43%. Among the 16 A. flavus strains, 8 possessed all 5 key genes of the aflatoxin biosynthetic pathway but only 4 showed the true aflatoxigenic capacity as confirmed by HPLC/MS-MS analysis (AFB1 range: 0.52-1030 µg/L). The most frequent mycotoxin was Ochratoxin A (OTA), occurring in 100% of the samples at mean concentration of 33.6 µg/kg while Fumonisin B1 (FB1) occurred in 97% of the feed samples at mean concentration of 247.1 µg/kg. Only one sample was contaminated by Aflatoxin B1 (5.84 µg/kg), classified as carcinogenic to humans. Our results confirm that feedstuffs can contribute to contamination of the work environment, and tasks involving their handling may represent critical procedures that expose personnel to airborne toxigenic fungi and mycotoxins.