Effectiveness of hermetic maize grain storage technology in limiting aflatoxin exposure in women and children from smallholder farming areas

摘要

The longitudinal study assessed the effectiveness of hermetic storage technology in limiting aflatoxin exposure among women aged 15-45 years and children under five years of age from households in selected smallholder farming areas of Zimbabwe. Exposure levels were determined by measuring aflatoxin M-1 (AFM(1)) in urine samples from women and children every three months during the 2015/2016 storage season for nine months. After extraction and immunoaffinity column clean up, AFM(1) was determined by high performance liquid chromatography. Generally, the proportion of AFM(1) positive urine samples from women increased throughout the grain storage season from 5.4% (n=23) (geometric mean (GM) 1.62 mu g/l) at harvest to 75% (n=315) (GM 48.35 mu g/l) nine months later (range limit of quantification (LOQ)-217.29 mu g/l). In urine samples from children, AFM(1) positive samples increased from 2.2% (n=4) (GM 0.78 mu g/l) at harvest to 72.5% (n=98) (GM 22.81 mu g/l) nine months later (range LOQ- 135.00 mu g/l). Urinary AFM(1) was significantly higher in samples from participants using conventional storage (GM 62.28 mu g/l; range LOQ-217.29 mu g/l) compared with samples from participants using hermetic technology (GM 31.95 mu g/l; range LOQ-157.71 mu g/l. There was no significant difference in AFM(1) concentrations in urine samples from participants consuming grain from metal silos and hermetic bags (P>0.05) hence the two technologies are equally effective in limiting exposure to aflatoxins in humans. The study concluded that aflatoxin exposure levels among women and children from small-holder farming areas increase throughout the postharvest season and the use of hermetic storage technology resulted in up to 33.2% decrease in frequency of detection and 48.7% decrease in levels of AFM(1) compared to conventional storage technologies. Thus hermetic grain storage can be an effective technology recommended for limiting aflatoxin exposure in smallholder farming populations.