Effect of Post-harvest Handling Knowledge and Practices of Small-scale Maize Farmers in Trans Nzoia County on Mycotoxin Contamination of the Grains

Abstract

Maize (Zea mays L.) is a vital grain that is rich in starch and is considered the staple food of Kenya. The crop is highly productive in ecological zones that have its favorable climate; however, the grain is highly susceptible to mycotoxin contamination which is greatly attributable to poor postharvest handling practices. Little information exists on maize postharvest management especially among the small-scale farmers who are the majority in Kenya. There is lack of standard postharvest, handling, storage procedures for maize grains which contributes to huge postharvest losses due to mycotoxin contamination. The study is aimed at understanding the post-harvest knowledge of the small-scale farmers and the practices employed in their day to day activities and their impact on the aflatoxin levels on the final product. A baseline survey was conducted using semi-structured questionnaire. A total of 200 respondents were interviewed. The current findings indicate that maize farming in Trans Nzoia consisted of male (67%) as compared to female (33%) responents. Male respondents had a higher knowledge score on postharvest practices in comparison to their females counterparts, however, this was not significant (p >0.05). The level of education of respondents was significantly associated (•=37.49a, p<0.05) with their knowledge on mycotoxin contamination. More than eight in every ten respondents (83.2%) had knowledge that inadequate drying (high moisture content) of maize and long periods exposes maize to the risk of mycotoxin contamination. Majority of the respondents (49.5%) relied on the casual laborer’s as source of human labor during harvesting. Additionally, majority (88.4%) had knowledge that poor ventilation in the storage facility causes fungal contamination, mould growth and the eventual mycotoxin contamination. Moreover, most of the respondents (83%) associated mycotoxins with cause of diseases in humans. Total aflatoxin levels in the initial sample extended from 0.00 to 9.12 μg/kg, with a mean of 1.96 μg/kg. Aflatoxin levels were found to be between 3.69 and 15.43 μg/kg after two months of storage, with a mean of 2.96 μg/kg. Initial total fumonisin concentrations ranged between 0.00 and 1.36 μg/kg, with a mean of 0.44 μg/kg. After two months of storage, fumonisin levels ranged from 0.00 to 1.51 μg /kg, with a mean of 0.60 μg/kg. Only 9.68 percent and 38.71 percent of the samples, respectively, had levels of Aflatoxin and fumonisin above the WHO-recommended levels of 10ppb and 500ug/kg, respectively. The study concludes that mycotoxin contamination of maize pre and postharvest among small-scale farmers was evident in Trans Nzoia and measures should be implimented to reduce the levels of contamination. Trainings of farmers and dispatch of additional extension officers can help improve the knowledge levels of farmers.