Aflatoxigenic fungal contamination in stored cereals and legumes: evidence from Zaria, Kaduna State, Nigeria

Abstract

Food security is threatened by spoilage and contamination, particularly in developing countries. Aflatoxins are mycotoxins produced by Aspergillus species of fungi. They are a significant public health hazard, affecting food quality and leading to economic losses. This study investigated aflatoxigenic moulds in stored cereal grains and legumes in Zaria, Kaduna state. Twelve samples; three each of groundnuts, soybeans, tigernuts, and rice, were collected from three locations and analysed for proximate composition. Fungal isolation and identification, as well as screening for aflatoxin production was also carried out using standard microbiological procedures. Results of proximate composition showed varying values of parameters such as moisture, proteins, lipids, ash, fibre and carbohydrates content. Fungal isolates identified were Aspergillus flavus (50%), Aspergillus fumigatus (33.33%), Aspergillus niger, as well as Penicillium species (8.33%). A. flavus was found in groundnuts (100%), tigernuts (66.67%), soybeans (33.33%), but not found in rice (0%). Out of the six A. flavus isolated, four were found to be aflatoxin producers, with 100% and 50% occurrence in groundnuts and tigernuts, respectively. Owing to the results generated in the study, it can be concluded that most of the investigated crops were contaminated with aflatoxigenic moulds, thereby posing a serious health hazard. Improved storage facilities, farming practices and public awareness are recommended to ensure adequate protection for public health.