Quantitative risk assessment for aflatoxins in beans from northern Tanzania

Abstract The study focussed on quantitative risk assessment for population exposure to aflatoxins by consuming beans from bean farmers in three villages; Long, Sabilo and Seloto in Babati District, Northern Tanzania. Aflatoxin levels were determined in a total of 144 bean samples; a total of 38 samples were collected from harvesting beans, while 106 samples were collected from stored beans. This kind of assessment allows modelling bean consumption data (kg/kg body weight (bw)/day) using an estimated average weight of an adult of 60 kg with previously collected data for total aflatoxin (AF) contamination (μg/kg) beans samples from the 2013/14 survey. Consumption was estimated by using the minimum annual per capita consumption of beans in Tanzania of 13.02 kg (which is equivalent to 35.67 g/day) and the exposure assessment was performed with the @RISK analysis software. Results from the assessment showed exposure for lower bound (LB) having a mean value of 1.06, 0.79 and 0.95 ng/kg bw/day in Long, Sabilo and Seloto villages, respectively, while for the medium bound (MB) the mean values were 1.33, 1.07 and 1.26 ng/kg bw/day, respectively, and for the upper bound (UB) the values were 1.65, 1.38 and 1.58 ng/kg bw/day, respectively. The margins of exposure (MoE) from this study were below 10,000 for all scenarios and this is of public health concern. Even though all samples had aflatoxin contamination below the maximum tolerable limit (MTL) of 4, 10 and 20 μg/kg for aflatoxins in cereals and pulses in the EU, the East African Community (EAC) and the USA, there is still a serious long-term health implication. Meeting MTL will not by itself guarantee food safety, but using the data collected and available on various health effects from aflatoxin and other mycotoxins, it is important to incorporate them into a risk assessment and show how excessive consumption of foods meets MTLs can still carry significant public health risks.