Developing integrated strategies to reduce the disease burden of mycotoxin contamina-tion in Ethiopia

Smallholder farmers in Ethiopia have limited resources and inadequate knowledge of good agricultural and storage practices, resulting in frequent mycotoxin contamination of staple crops. Information on the health impacts of mycotoxins and the relationships between farming practices and contamination remains fragmented. Generating evidence on contamination levels, associated health burdens, and management practices is therefore essential to inform policies that protect public health and support international trade.This PhD research investigated pre- and post-harvest practices related to mycotoxin contamination in maize and sorghum. A systematic literature review revealed that several traditional maize pre-harvest practices-including shallow ploughing, suboptimal fertilizer and pesticide use, subjective harvesting decisions, prolonged sun drying, and kernel damage during shelling-are positively associated with mycotoxin contamination. In addition, improper indoor and outdoor storage practices are also positively associated with mycotoxin contamination due to moisture ingress, elevated temperatures, and insect infestation. Although improved technologies such as solar bubble dryers and PICS sacks show potential to reduce contamination, their adoption remains limited due to supply chain constraints.For sorghum, field studies were conducted to assess the relationships between both pre-harvest and storage practices and mycotoxin contamination. Freshly harvested sorghum samples were collected from 120 smallholder households. Mycotoxin analysis showed that 75% of the sorghum samples contained at least one mycotoxin, with 23 of the 33 tested mycotoxins detected. Most regulated mycotoxins were below European Union (EU) limits, except for ochratoxin A, which exceeded the limit in 4% of samples. Significant associations were identified between mycotoxin contamination and pre-harvest practices, including sowing method, fertilizer type, crop rotation, and seed treatment. After six months of storage, 88% of the sorghum samples were contaminated, with a small proportion exceeding EU limits for aflatoxins, ochratoxin A, and zearalenone. Storage practices such as the type and placement of storage structures, insecticide use, and the knowledge and experience of the person responsible for storage were significantly associated with mycotoxin contamination. Health risk assessment indicated that exposure to fumonisin through sorghum consumption was well below international safety limits. However, aflatoxin exposure suggested a potential public health concern based on margin of exposure values, although the estimated liver cancer risk and disease burden (DALYs) were relatively low.