Immobilized sodium metabisulphite food grade preservative bags with aslow release of sulphur dioxide to control mycotoxins in stored legumes and cereals.

Linking East and West African farming systems experience into a BELT of sustainable intensification Immobilized sodium metabisulphite food grade preservative bags with a slow release of sulphur dioxide to control mycotoxins in stored legumes and cereals. PRACTICE ABSTRACT Authors: Carla Cervini (1), Anil Graves (1), John Bidzakin (1), Francis Obuoro Wayua (2), Sheila Okoth (3), Kelvin Mtei (4) Practice Abstract n.4 The EWA-BELT Project has received funding from the European Union's Horizon2020 research and innovation programme under agreement No 862848 ENGLISH Authors' affiliation: (1) Cranfield University, UK; (2) KALRO-National Sericulture Research Centre, Kenya; (3) University of Nairobi, School of Biological Sciences, Kenya; (4) Nelson Mandela African Institution of Science and Technology, Tanzania Cranfield University (CRAN), in collaboration with African partners based in Kenya and Tanzania, led research on post-harvest strategies to control mycotoxins in stored crops. The study focused on the use of food-grade sodium metabisulphite (NaMBS) bags, which slowly release sulphur dioxide (SO₂). NaMBS is commonly used as a post-harvest antifungal treatment for table grapes, effectively controlling fungal spoilage caused by Botrytis cinerea (grey mould) during storage. This research explored the adaptation of NaMBS pads, designed to gradually release SO₂, into 3 kg capacity storage bags as a potential strategy for preventing fungal spoilage and mycotoxin production in various crops. Lab tests on unshelled peanuts under dry (0.85 aw[1]) and wet (0.95 aw) conditions showed SO₂ bags completely inhibited fungal growth in naturally contaminated peanuts, while reducing fungal loads by 72% and 49% in A. flavus-inoculated peanuts at 0.85 and 0.95 aw, respectively. Aflatoxin B1 (AFB1) was also inhibited. Further trials on shelled peanuts at 0.85 (dry), 0.90 (relatively dry), and 0.95 (wet) aw over 21 days showed a 45% fungal reduction when peanuts were stored in SO2-releasing bags at 0.90 aw. AFB1 was undetectable at 0.85 and 0.90 aw, while at 0.95 aw, it was reduced 10-fold compared to peanuts kept in plastic bags (control conditions). Ongoing trials by KALRO and the University of Nairobi (Kenya) and NM-AIST (Tanzania) are evaluating SO₂ bags for safe storage of finger millet, maize, sorghum, and peanuts at 13%, 15%, 17% and 20% (from slightly high to unsafe) moisture content, compared with gunny and hermetic PICS bags over six months. Findings confirm SO₂ bags effectively reduce fungal spoilage and mycotoxin contamination, especially in moderately dry conditions. Future research should optimise scalability for widespread adoption in smallholder systems. GA 862848Practice abstract n.4 Immobilized sodium metabisulphite food grade preservative bags with a slow release of sulphur dioxide to control mycotoxins in stored legumes and cereals. [1] Aw: “free water” or “water activity”. Free water or the water activity level is the amount of water not bound with other non-water molecules. Since unbonded water supports the growth of microorganisms, the stability or shelf life of food is partially determined by the amount of free water in a product. It is the ratio of a product’s vapor pressure to the vapor pressure of distilled or pure water, that it is equal to 1. Linking East and West African farming systems experience into a BELT of sustainable intensification GA 862848Practice abstract n.4 The sole responsibility for the content of this publication lies with the authors. The publication reflects the views of the authors and the European Commission cannot be held responsible for any use which may be made of the information contained therein www.ewabelt.eu