Post-Harvest Knowledge, Perceptions and Practices by Farmers and Diversity of Fusarium Species and Fumonisin Contamination of Maize from Rift Valley and Lower Eastern Regions of Kenya

Abstract

Maize serves as a staple food in many Sub-Sahara African Countries with 90% of the Kenyan population depending on it. Although the area under maize cultivation has been increasing in Africa, its production has been reducing. Heavy post-harvest losses of the crop during storage have been a big challenge. Maize is susceptible to insects and fungal infestations leading to mycotoxin contamination including aflatoxin and fumonisins. Fumonisins are produced by the Fusarium species and despite its known health hazards, there is a dearth of data on fumonisin contamination in Kenya. Therefore, the main objective of this study was to determine post-harvest perceptions, knowledge and practices by farmers and diversity of Fusarium species and fumonisin contamination of maize from Rift Valley and Lower Eastern Regions of Kenya. A descriptive cross-sectional study was carried out among 165 and 149 farmers in the Rift Valley and Lower Eastern Regions of Kenya respectively. An interviewer administered semi-structured questionnaire was used to collect data from the farmers. Maize grains samples were collected for laboratory analysis. In the laboratory, the collected samples were cultured for Fusarium and other fungal growth. Determination of fumonisin contamination levels was also carried out. Data was analyzed using Statistical Package for Social Sciences (SPSS) version 24.0, with descriptive and inferential statistics used. Data from the two regions were compared using Chi-square and fisher’s exact tests for categorical variables and two sample t-test and its non-parametric form, Mann-Whitney U test for comparison of means for continuous variables. A p value of < 0.05 was considered statistically significant. Majority (58.6%) of the respondents were females and farming was the main economic activity. The median quantity of maize harvested after shelling in the two regions was 6.5 bags (585 kg) (IQR=2-19) per household. The median amount of maize put aside before shelling as a result of rotting was 20 kg (IQR=0-90) per household. The quantity of discolored and mouldy grains consumed ranged from 0 - 90 kgs per household, 7 (2.2%) respondents consumed mouldy maize, 36 (11.5%) fed the mouldy maize to cows and 19 (6.1%) fed it to poultry. A small percentage (3.5%) believed that mouldy maize is safe for human consumption, 23.6% for animal consumption, while 15.0% considered it safe for brewing with the differences between the two regions (24.8% in RV verses 4.0% in LE) being statistically significant (p < 0.05). More than half 193 (61.5%) had good knowledge on causes and methods of minimizing moulding. More farmers from RV, 134 (81.2%) had good level of knowledge compared to 59 (39.6%) in LE, and the regional difference was statistically significant (P-value<0.001). Concerning storage practices, nearly half (48.4%) of the respondents stored maize while still on cobs in a separate room, 47.1% left it in the field without covering. Most (33.1%) farmers from the Lower Eastern consumed and sold maize while still green. Infestation by Fusarium species in the maize samples collected was 30.1% with F. verticillioides accounting for 80.8% of the Fusarium species isolated. Lower Eastern Region had higher Fusarium isolates compared to Rift Valley Region (P <0.05). Of the 200 samples tested 133 (66.5%) had fumonisin levels below the level of detection, 63 (31.5%) samples had fumonisin levels ranging from 0.1 ppm - 4.0 ppm while 5 (2.5%) samples had levels that were above 4.0 ppm. Lower Eastern had significantly higher number of samples with detectable level of fumonisin compared to Rift Valley (P-value <0.001). This study confirms that maize samples from Lower Eastern and Rift Valley are contaminated with significant levels of Fumonisins with a potential of negative health consequences.Poor post-harvest management practices among maize farmers and ignorance are likely risk factors for post-harvest losses and mycotoxin exposure with potential health and economic consequences. This calls for education campaigns on better post-harvest practices among famers as well as more research on the potential health consequences that these detected fumonisins pose to the consumer.