Prevalence of Mycotoxin-Producing Fungi in Brassica Oleracea sold in Port Harcourt Metropolis, Nigeria

This study investigated the prevalence of mycotoxin-producing fungi from Brassica oleracea sold in Port Harcourt metropolis, Nigeria using molecular techniques. Brassica oleracea showing signs of fungal infestations were collected from markets across Port Harcourt Metropolis, Nigeria. The samples were first observed for signs and symptoms. Fungi were isolated from the vegetable following standard methods. Capacity to produce mycotoxin by the fungal isolates was investigated by polymerase chain reaction (PCR)-based screening of the isolates. The presence of five mycotoxigenic genes: nor1, tri6, otanps, fum13 and Zea encoding for the following mycotoxins: aflatoxin, trichothecene, Ochratoxin A, fumonisin, and zearalenone, respectively were evaluated. Fourteen fungi were isolated from the vegetable, out of which four isolates were positive for mycotoxigenic genes. This represents a 28.6% prevalence rate. The mycotoxigenic genes found in the isolates included Ochratoxin A, Trichothecene and Aflatoxin. Trichothecene was produced by Pithomyces chartarum RCBBR_Sf5 and Fusarium longifundum RCBBR_Mf4 while aflatoxin and ochratoxin A were produced by Trametes duplexa RCBBR_Mf1 and Trametes versicolor RCBBR_Sf2a, respectively. The ITS gene sequences of the four fungi have been deposited in GenBank under the accession numbers OR816040; OR816043-OR816045. This study has demonstrated that mycotoxin-producing fungi are prevalent in Brassica oleracea sold in Port Harcourt Metropolis. This observation raises both public health and food security concerns.