Isolation and characterization of fusarium species and sumonisins contamination in maize from lower Eastern and Rift valley regions of Kenya

Abstract

Maize serves as a staple food in many Sub-Sahara African (SSA) Countries. It is mostly susceptible to mycotoxins including aflatoxin and fumonisin contamination. Fumonisins are produced by the Fusarium species, predominantly Fusarium verticillioides. Fumonisins’ health hazards are documented in many parts of the world. However, few studies exist on fumonisin contamination in maize locally. The presence of Fusarium species and the associated fumonisin contamination of maize grown in Rift Valley and Lower Eastern regions of Kenya were assessed. Maize samples were collected from randomly selected households in three Counties from each of the two regions. Isolation and characterization of Fusarium species was done using Daniel et al., (2011) protocol. Envrologix Quick Tox Kit was used to quantify fumonisin levels. Aspergillus species was the most prevalent fungi species isolated (50.3%) followed by Fusarium species (39.3%) with F. verticillioides accounting for 80.8% of all Fusarium spp. Of the 200 samples analyzed, 133 (65.5%) had fumonisin levels below the level of detection (< 0.1 ppm), 63 (31.5%) had fumonisin level of between 0.1 ppm- 4.0 ppm and 4 (2.0%) sample had fumonisin levels of more than 4.0 ppm. Lower Eastern Region had higher proportion of samples with detectable fumonisin levels compared to Rift Valley Region (55.4% vs 11.1%). In conclusion Fusarium verticillioides commonly associated with fumonisin contamination of maize was a common fungus isolated in the study regions. It also showed that some of the maize samples consumed by the respondents have fumonisin levels that are above the internationally accepted levels. These results suggest that people are likely to be exposed to fumonisins that has been associated with adverse health hazards