A Prospective Approach for Screening of Potential Evolution of Aflatoxins in Fish and Fish Feed: Molecular and Afla Fluorometry Assays.

The transmission of aflatoxins from fish products to consumers primarily occurs through the contamination of fish flesh and feed by aflatoxigenic fungi. This study comprehensively examined the prevalence and extent of fungal contamination in the flesh of Oreochromis niloticus and Mugil cephalus, as well as in fish feed. Furthermore, it assessed the aflatoxin-producing potential of Aspergillus flavus through fluorometric and molecular assays, providing critical insights into the risks associated with mycotoxin contamination in aquaculture products. O. niloticus and M. cephalus (n = 20 for each species) and fish feed (n = 30) were collected from fish farms and feed markets in Ismailia Governorate, Egypt. The total mold counts exceeded the permissible limit in 25% of the examined O. niloticus samples and 53.3% of the examined feed samples. A. flavus was the predominant species recovered from O. niloticus (48%), M. cephalus (75%), and feed samples (32.4%). All samples tested positive for total aflatoxins using afla fluorometry. Additionally, 60% of O. niloticus and 80% of fish feed samples exceeded global mycotoxin regulatory limits. Among the 33 Aspergillus flavus isolates, only 10 were toxigenic, testing positive for the aflatoxin regulatory (aflR) gene. Sequence analysis of the aflR gene revealed a high genetic similarity between the examined strain and A. flavus strains from Italy, Egypt, and Saudi Arabia. These findings highlight fish feed as a major source of mycotic infections and aflatoxin contamination in fish flesh. Fish feed represents a primary source of mycotic infections and aflatoxin contamination of fish flesh. This source could constitute a health hazard for consumers. Therefore, implementing strict quality control measures for feed storage and processing, along with regular monitoring of aflatoxin levels in aquaculture products, is essential to mitigate health risks and ensure food safety. The combination of morphological and molecular assays is recommended for truthfully monitoring aflatoxogenic A. flavus.