Assessment of Aflatoxin Levels, Microbiological Quality, Nutrient Composition and Physical Characteristics in Groundnut Flour (Nsinjiro) Sold in Local Markets in Central and Southern Regions of Malawi

Abstract

Assessment of aflatoxin levels, microbiological quality, nutrient composition and physical characteristics was carried out on 38 groundnut flour samples from 2 regions of Malawi where groundnuts are produced and consumed in substantial quantities. The local market list was obtained from the Ministry of Local Government Office. Samples were randomly purchased in the markets. Aflatoxins (B1, B2, G1, and G2) were analysed using the HPLC method while microbial loads, nutrient composition and physical characteristics were determined following various standard methods. The data were analysed using SPSS and some results were reported as Mean ± SD. The findings revealed that, 37 of the 38 samples examined were contaminated with aflatoxin, with total aflatoxin ranging from 0 to 77.08 ± 16.50 ppb which are higher than the 3 ppb limit permitted in Malawi. Twenty eight samples overall exceeded the thresholds for Malawi Bureau of Standards. The permissible limit of microbial loads for Malawi is 10,000 cfu/g whiles the ICMSF is 500,000 cfu/g, hence E. coli (0-30 cfu/g), Salmonella (0-70 cfu/g) icnluding Total coliform (0-80 cfu/g) were not acceptable by both limits respectively. Yeast and mould count (0-90 cfu/g) and Total Aerobic Plate count (0-210 cfu/g) were below both restrictions respectively. Samples had nutrients like protein (30.67 %), carbohydrate (37.87 %), fat (43.90 %), and ash (3.43 %) respectively. The samples' colour was light with L* values ranging from 49.79 ± 6.73 to 59.88 ± 0.43. These results indicate that groundnut flour studied was susceptible to aflatoxin and microbial contamination hence aflatoxin and hygienic monitoring prior to marketing is required.