Abstracts of Presentations to the Working Session on Improving Predictive Modeling of Mycotoxin Risk for Africa Held at the 3rd ASM2022 on 7 September 2022, in Stellenbosch, South Africa.

In 2008, the African Postharvest Losses Information Systems project (APHLIS, accessed on 6 September 2022) developed an algorithm for estimating the scale of cereal postharvest losses (PHLs). The relevant scientific literature and contextual information was used to build profiles of the PHLs occurring along the value chains of nine cereal crops by country and province for 37 sub-Saharan African countries. The APHLIS provides estimates of PHL figures where direct measurements are not available. A pilot project was subsequently initiated to explore the possibility of supplementing these loss estimates with information on the aflatoxin risk. Using satellite data on drought and rainfall, a time series of agro-climatic aflatoxin risk warning maps for maize was developed covering the countries and provinces of sub-Saharan Africa. The agro-climatic risk warning maps for specific countries were shared with mycotoxin experts from those countries for review and comparison with their aflatoxin incidence datasets. The present Work Session was a unique opportunity for African food safety mycotoxins experts, as well as other international experts, to meet and deepen the discussion about prospects for using their experience and their data to validate and improve agro-climatic risk modeling approaches.

Long Term Monitoring (2014⁻2018) of Multi-Mycotoxins in South African Commercial Maize and Wheat with a Locally Developed and Validated LC-MS/MS Method.

Mycotoxins occur worldwide in the major grains, and producers, traders and processors are all challenged to prevent serious health problems for consumers. The challenges originate with pre-harvest fungi infections in the grain fields, increased contamination during improper storage and, finally, the mycotoxin accumulation in commercial food and feed products. Little is known about the multi-mycotoxin occurrence in maize and wheat commercially produced in South Africa. This is the first comprehensive study that reports on the multi-mycotoxin occurrence in South African produced maize and wheat crops after harvest, over four production seasons, in all the production regions of the country. The study was made possible with the development of a fit-for-purpose, cost-effective LC-MS/MS multi-mycotoxin method, validated for 13 "regulated" mycotoxins. A low mycotoxin risk was found in South African produced wheat, with only deoxynivalenol (DON) in 12.5% of the 160 samples at levels well below the 2000 µg/kg South African (SA) regulatory level. It was concluded that aflatoxin B1 (AFB1) is seldom present in South African produced commercial maize. The concentrations, regional variation and seasonal trends of deoxynivalenol and fumonisins, the two most prevalent mycotoxins, and of zearalenone (ZON), are reported for white and yellow maize in all the production provinces, based on the analytical results of 1400 maize samples. A threefold to eightfold increase in deoxynivalenol mean concentrations in white maize was observed in the main production regions in the fourth season, with 8.9% samples above 2000 µg/kg. A strong correlation was found between higher deoxynivalenol concentrations and the presence of 15-acetyl-deoxynivalenol (15-ADON). The mean fumonisin concentrations were well below the 4000 µg/kg South African regulatory value. A possible shift in the incidence and severity of mycotoxigenic Fusarium spp. in the provinces must be investigated. The variations and trends highlight the importance of a continuous monitoring of multi-mycotoxins in South Africa along the grain value chain.