Prevalence of aflatoxins in dietary staples in the border County of Busia, Western Kenya

Abstract

Aflatoxins, secondary metabolites of some Aspergillus fungi, are of public health importance. They are major contaminants of cereals and tubers. Data on prevalence of aflatoxin contamination of sorghum, millet and cassava in Busia County are limited. The extent of aflatoxin contamination in dietary staples in Busia County were assessed and potential sources associated with the contamination evaluated. A tool designed to collect sociodemographic profile, food sources and storage locations and vessels and food consumption habits of respondents was loaded onto an Open Data Kit and used in 3 subcounties. Quantitative data were analyzed using SAS version 15 software. Maize, millet, sorghum, cassava and groundnut samples were collected from 469 households. Competitive Enzyme-linked Immunosorbent Assay method was used to determine total aflatoxin levels in food samples. Sixty-eight percent of the maize samples were sourced from the market. Approximately 75% of maize samples were stored in polypropylene sacks. Samples of all five foods had detectable levels of aflatoxin. Overall, maize had the highest level of contamination (mean 100 ppb; SD 252.9; range 1-1584 ppb) with about a third of maize samples above the East African Community regulatory limits (10 ppb). The levels of aflatoxin ranged from 0.3 to 740 ppb in sorghum, 0.5 to 15 ppb in cassava, from 0.5 to 12 ppb in millet and from 0.1 to 2.8 ppb in groundnuts. The odds of contamination above 10 ppb for market-sourced maize was 1.2 times higher than homegrown maize (OR 1.185, CI 0.554, 2.534). Sorghum stored in buckets had a 12.81 likelihood of having higher than allowable limits of aflatoxin (OR 12.82, CI 2.566, 63.992) than when stored in polypropylene sacks. Aflatoxin is prevalent in the dietary staples consumed in households within Busia County. Residents are at risk of chronic exposure to aflatoxin. Enhanced market surveillance within the county is recommended.