Conclusions
Our results indicated that corn, soybean meal and finished feed of poultry feed mill are contaminated with various fungal genera by different levels sometimes higher that the standard limits. Contamination with potentially mycotoxigenic fungi especially Aspergillus species may be considered as a human public health hazard.
Methods
Eighty five samples of corn, soybean meal and poultry finished feed were collected from nine poultry feed factories located in three provinces i.e. Tehran, Alborz and Qom in Iran from October 2014 to January 2015. Samples were cultured on Sabouraud dextrose agar (SDA), Aspergillus flavus and parasiticus agar (AFPA) and dichloran rosebengal chloramphenicol agar (DRBC) and incubated at 28 °C for 7-10 days. Purified fungal colonies were identified by a combination of macro- and microscopic morphological criteria. For determining the rate of fungal contamination, samples were cultured on SDA and colony forming units (CFUs) were calculated.
Results
A total of 384 fungal isolates belonging to 7 genera of filamentous fungi and yeasts were obtained from corn (124 isolates), soybean meal (92 isolates), and feed before (72 isolates), and after pelleting (96 isolates). The most prominent fungal isolate in corn, soybean meal and feed before pelleting (feed as mash form) was Fusarium but in feed after pelleting was Aspergillus. Among 5 Aspergillus species isolated, potentially aflatoxigenic A. flavus isolates was predominant in corn (46.6%), soybean meal (72.7%) and poultry finished feed (75%). CFUs results indicated that 9/22 corn samples (40.9%), none of 22 soybean meal samples, 19/41 finished feed (46.3%) were contaminated higher than the standard limit. Conclusions: Our results indicated that corn, soybean meal and finished feed of poultry feed mill are contaminated with various fungal genera by different levels sometimes higher that the standard limits. Contamination with potentially mycotoxigenic fungi especially Aspergillus species may be considered as a human public health hazard.