Aflatoxin Analysis in Staple Food Cereals and Assessment of Households’ Awareness on its Management in Tharaka-Nithi County, Kenya

Abstract

Aflatoxin is a poisonous substance produced by fungi. Crops infestation is inevitable and numerous evolving nations collectively with Kenya do not regularly test their main foods for aflatoxins contamination. Consumption and sale of mycotoxins infested cereals and grains has the risk of contributing to a diversity of severe medical complications in people. Context-specific information on the aflatoxin occurrence in the County makes it possible to document vulnerable staple crops and the level of toxicity in the County. Measurement of exposure using the factors that influence the choice of the food together with the presence of these harmful mycotoxins can be used to demonstrate how this contamination occurs in food, map the aflatoxin hot spots in the County and inform the choice of the most effective control approaches. However, there is lack of local data on aflatoxin contamination in Tharaka-Nithi County to inform interventions chiefly due to lack of local research, testing facilities, and qualified personnel. The main purposes of the research included: to evaluate the levels of aflatoxin in cereals commonly used as staple foods sourced from households and marketplaces, to evaluate households’ awareness on suitable conditions for storage of foods regarding aflatoxin contamination, and to identify factors contributing to aflatoxin contamination. Samples were collected from Tharaka-South and TharakaNorth Sub-Counties which had three Wards with a total of 24 Sub-Locations. 3 Households per Sub-Location that had some stock of the crops of interest were randomly chosen from the villages in each Sub-Location. Three major open-air markets were also selected based on size for the collection of the samples. During the collection of the samples, observations were done, and a questionnaire used to determine the study respondents’ awareness of aflatoxin contamination and knowledge of the potential causes of contamination. Analysis for aflatoxin levels was conducted using the ELISA Kit. The information collected during household interviews was analyzed using SPSS version 22. The main cereals used as staple foods among households in the County as per the study results included: pearl millet, sorghum, maize, green grams, and cow peas. Overall, aflatoxin contamination in 25.8% of sampled cereals was above the legal threshold of 10ppb Kenyan standards with 17.2% of cereals exceeding the established human tolerance levels of greater than 20ppb. The aflatoxin contamination levels of 44.4% of the market samples was greater than the Kenyan tolerable limits. Based upon the Chi-Square test for association, it was evident that level of aflatoxin was associated with the type of cereals and grains (p-value 0.001, which was less than 0.05 at 95% confidence level). Therefore, cereals and grains levels of contamination differed as they were exposed. Based upon the t-Test for Equality of Means, the difference was not significant (p-value for Maize= 0.89, Sorghum= 0.47 and Pearl Millet=0.64, all of which are greater than 0.05). Thus, there was no difference in mean level of aflatoxin in the cereals and grains in the two study areas. Furthermore, the t-Test for Equality of Means, showed that there was no difference in mean level of aflatoxin in the cereals and grains collected from the markets and households (p-value for Maize=0.294, Sorghum=0.422 and Pearl Millet=0.918, all of which are greater than 0.05). Majority of the farmers (84.7%) were aware of aflatoxin as a dangerous poison found in cereals and grains especially those that are not properly dried to safe moisture content. However, detailed information on the nature, formation, effects, prevention, and control of aflatoxins was scanty and inconsistent. The study provided crucial information on the aflatoxin contamination levels of these major cereals and grains and on households’ knowledge on aflatoxin management. This data will be key in bringing issues to light of the presence of these harmful mycotoxins in staple foods and increase the community’s knowledge and skills on the use of sustainable, low-cost post-harvest management practices to decrease the contamination. This will enhance the well-being of populations in the County and ultimately the national food security.