Simple intervention method to reduce fumonisin exposure in a subsistence maize-farming community in South Africa

Abstract

In the Centane magisterial area of South Africa, high rates of oesophageal cancer have been associated with home-grown maize contaminated with fumonisins. The aim of this study was to implement a simple intervention method to reduce fumonisin exposure in a subsistence-farming community. The hand-sorting and washing procedures, based on traditional maize-based food preparation practices, were previously customised under laboratory-controlled conditions. Home-grown maize and maize-based porridge collected at baseline were analysed for fumonisin B₁, B₂ and B₃. The geometric mean (95% confidence interval) of fumonisin contamination in the home-grown maize at baseline was 1.67 (1.21–2.32) mg kg⁻¹ and 1.24 (0.75–2.04) mg kg ⁻¹ (dry weight) in the porridge. Fumonisin exposure was based on individual stiff porridge consumption and the specific fumonisin levels in the porridge (dry weight) consumed. Porridge (dry weight) consumption at baseline was 0.34 kg day⁻¹ and fumonisin exposure was 6.73 (3.90–11.6) µg kg⁻¹ body weight day⁻¹. Female participants (n = 22) were trained to recognise and remove visibly infected/damaged kernels and to wash the remaining maize kernels. The discarded kernels represented 3.9% by weight and the fumonisins varied from 17.1 to 76.9 mg kg⁻¹. The customised hand-sorting and washing procedures reduced fumonisin contamination in the maize and porridge by 84 and 65%, respectively. The intervention reduced fumonisin exposure by 62% to 2.55 (1.94–3.35) µg kg⁻¹ body weight day⁻¹. This simple intervention method has the potential to improve food safety and health in subsistence-farming communities consuming fumonisin-contaminated maize as their staple diet.

Keywords:

• mycology
• chromatography, HPLC
• clean-up
• risk assessment
• mycotoxins, fumonisins, Fusarium
• cereals and grain

Acknowledgements

The authors acknowledge support from the Sir Halley Stewart Trust and CPW and YYG from NIEHS, USA grant no. ES06052. We thank John Mokotary for driving expertise and technical assistance, Nokhuthula Kulati for leadership and IsiXhosa translations, Nobobele Mpetsheni, Nozuko MBana and NobisSuthu Kulati for recruiting and interviewing the participants, R. Hulley and his family as well as the staff of the Trennery's Hotel for their invaluable assistance, and the participants without whom the study would not be possible.