Aflatoxins are naturally occurring toxic metabolites synthesized by certain species of Aspergillus, in particular Aspergillus flavus and Aspergillus parasiticus. Several types of aflatoxins such as B1, B2, G1, G2, M1, and M2 are produced by these fungal strains. Among these, aflatoxin B1 is the most toxic to mammals and induces cell injury. Epidemiological, clinical and experimental studies revealed that aflatoxins are toxic and carcinogenic to mammals. This study was designed to observe the total fungal count and the prevalence of aflatoxin-producing Aspergillus using polymerase chain reaction (PCR) in local food and feed products. A total of 102 food and feed product samples were randomly collected and primarily analyzed to observe the total yeast and mould count. Subsequently, Aspergillus species were isolated and screened for ver-1, apa-2, omt-1 genes of aflatoxin biosynthetic pathway using PCR assay. Thin layer chromatography (TLC) was performed to confirm the synthesis of aflatoxin in PCR-positive strains. It was observed that all tested samples were found contaminated with yeast and moulds having highest count in cotton seed cake samples. A total of 102 Aspergillus strains were isolated, in which 09 were positive to all three targeted genes, wherein 06 were A. flavus and 03 were A. parasiticus positive. All PCR positive strains produced aflatoxin B1 and B2, but not G1 and G2 when analyzed by TLC. It was observed that Aspergillus species were one of the most common contaminants in food and feed samples. Aflatoxigenic strains of Aspergillus were also frequent and it is important to devise strategies at local levels to control these aflatoxin producing strains at pre- and post-harvest stages.
Ibrahim, F., Jalal, H., Khan, A. B., Asghar, M. A., Iqbal, J., Ahmed, A., & Nadeem, G. (2016). Prevalence of Aflatoxigenic Aspergillus in Food and Feed Samples from Karachi, Pakistan. Journal of Infection and Molecular Biology, 4(1), 1–8. https://doi.org/10.14737/journal.jimb/2016/18.104.22.168