Attitudes to feed fermentation for aflatoxin management in maize in Kenya: Investigating aflatoxin reduction by yeast-fermentation

Aflatoxins are toxins produced by certain strains of fungi belonging to the species Aspergillus flavus and Aspergillus parasiticus during infection in the field, post-harvest, storage and processing. Aflatoxins are found especially in maize and also carry over into milk when contaminated feeds are fed to dairy cows. Feed fermentation could possibly be used to reduce the level of aflatoxin in animal feed. The project investigates, with survey interviews, if Kenyan farmers are willing to use novel fermentation methods to reduce the level of aflatoxin. The project will give better understanding of the farmers’ opinions and situation. The survey part involved 184 smallholder farmers in urban and peri-urban areas in Kasarani and Kisumu. Feed fermentation for aflatoxin reduction is not well researched. To address this approach the second goal of this project was to investigate how different yeasts could be used to degrade aflatoxins in Kenyan maize. A laboratory pilot-trial was performed to find out if yeast-based feed fermentation of aflatoxin-contaminated maize might degrade or otherwise reduce toxin levels. Aflatoxin in the control treatment should have been constant during the incubation period, because the maize is dry and stable, and in the control would not be affected by addition of water or different yeasts. However, since the maize sample in the bottle was not homogeneous, each treatment, including the control, showed variation in aflatoxin content. The water added to the fermentation treatments was not sufficient to support good growth of inoculated yeasts or other microbes which could ferment the maize, so no clear effect of fermentation was observed. The survey revealed that feed fermentation (or silage making) is not commonly practised in Kenya. During the survey, it was found that only 22% of the farmers practice feed fermentation and that they desire more knowledge about it. According to the survey 95% of the Kenyan farmers were positive about using a specific yeast for feed fermentation.