Browsing by Author "Menza, Nelson C."

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    Incidence, Types and Levels of Aflatoxin in Different Peanuts Varieties Produced in Busia and Kisii Central Districts, Kenya
    (Scientific Research Publishing, 2015) Menza, Nelson C.; Muturi, Margaret W.; Kamau, Lucy M.
    Busia and Kisii Central districts are areas in western Kenya that have repeatedly reported high levels of stunting growth in children and an increase in hepatocellular carcinoma (HCC); an aspect often positively associated with chronic exposure to aflatoxins especially through consumption of foods such as peanuts. The objectives of the study were to determine the incidence, types and levels of aflatoxin in different varieties of peanuts produced in Busia and Kisii Central districts. One hundred and two (102) peanuts samples were collected from farmers’ in each district. Aflatoxin types and levels of aflatoxins were analyzed using high performance liquid chromatography (HPLC) technique. All the peanuts samples from Kisii Central and 97.06% samples from Busia were contaminated with aflatoxins. However, aflatoxin was not detected in 2.94% of samples from Busia district. The levels of total aflatoxin ranges were 0.1 to 268 μg/kg and 1.63 to 591.1 μg/kg in peanuts from Busia and Kisii Central respectively. Majority of peanuts samples had levels within Kenya Bureau of Standards (KEBS) and European Union (EU) regulatory limits for total aflatoxins. Improved variety (Valencia red) had significantly lower aflatoxin contamination compared to local varieties (Uganda local red, Homabay local and Local red). Aflatoxins B1, B2, G1 and G2 were found in peanuts; B1 was the most predominant in both districts (t = 12.4, df = 3, P = 0.034). The levels of aflatoxins especially in peanuts from Kisii Central district were high (591.1 μg/kg) where 44.6% of samples analyzed were unfit for even animal feed (USFDA regulatory limit). An assessment on the levels of aflatoxins should be done by the relevant stakeholders in other key foods in the areas for example maize. The most lethal aflatoxin type B1 was found to be the most predominant peanuts from both districts of study. This calls for frequent aflatoxin screening of peanuts from the districts particularly aflatoxin type B.
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    Occurrence of Aflatoxigenic Aspergillus Species in Various Varieties of Peanuts Produced in Western Kenya
    (PrePrints, 2017) Menza, Nelson C.; Muturi, Margaret W.; Kamau, Lucy
    Aflatoxin contaminates foods including peanuts. Aflatoxin is a carcinogenic toxin mainly produced bty Aspergillus flavus. Other Aspergillus species that rarely produce aflatoxins are A. nomius and A. niger. Aflatoxin is associated with liver failure, hepatocellular carcinoma (HCC) and death. Recent studies have shown that peanuts in Kenya are highly contaminated with aflatoxins but information gaps exist on the characterization of the Aspergillus species that produce aflatoxins in peanuts in Kenya. Therefore, this gap necessitated the determination of the Aspergillus species producing aflatoxins in peanuts from the main growing districts of Busia and Kisii Central districts. One hundred and two (102) peanuts samples were collected from farmers’ in each district Aspergillus species were isolated from the peanut samples by using the dilution plate technique on modified Rose Bengal agar. Phenotypical characterization of the identified Aspergillus section flavus isolates from the peanuts samples was determined using the procedure of Mellon and Cotty. This study identified five (5) Aspergillus species as contaminants in peanuts analyzed in this study. They were Aspergillus flavus L-strain, Aspergillus flavus S-strain, Aspergillus parasiticus, Aspergillus niger and Aspergillus tamari. Overall, the occurrence of Aspergillus flavus L- strain and A. flavus S- strain were significantly higher than other species identified (H = 15.55, df = 4, P = 0.004) in peanuts from the two districts. However, A. flavus Sstrain was the most dominant species identified in the study with a mean occurrence of 45.1%. Aspergillus flavus L- strain was the most common isolate (58.8%) in peanuts from Busia district while A. flavus S- strain was the most common strain (60.2%) in peanuts from Kisii Central district. Overall, the occurrence of Aspergillus flavus L strain and A. flavus S strain were significantly higher than other species identified (H = 15.55, df = 4, P = 0.004) in peanuts from the two districts. However, A. flavus S-strain was the most dominant species (F=3.15, df =25, P=0.031) with an overall mean occurrence of 45.1%. The confirmation of occurrence of other species that produce toxins such as A. niger and A. tamarii which also produces cyclopiazonic acid suggests the need to screen peanuts for other carcinogenic mycotoxins
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    Oil Contents and Aflatoxin Levels in Peanuts Varieties Produced in Busia and Kisii Central Districts, Kenya
    (OMICS International, 2016) Menza, Nelson C.; Muturi, Margaret W.; Kamau, Lucy M.
    Busia and Kisii Central districts have repeatedly reported high levels of aflatoxins in foods. The objectives of the study were to determine oil contents and the relationship between oil contents and the levels of total aflatoxin in peanuts varieties produced in the two districts. Three samples of each of the four (4) varieties of peanuts obtained from Busia; Valencia red, Uganda local, Homa Bay local and local red and 3 varieties from Kisii Central; Valencia red, Uganda local and Homa Bay local were analyzed and the average oil contents of the samples in each variety determined. The oil contents of peanuts were determined by a standard Soxtec extraction method and total aflatoxins were analyzed using high performance liquid chromatography (HPLC) technique. Peanuts from Busia district had significantly higher oil contents compared to those from Kisii Central (t=3.22, df=6, P=0.012). Peanuts of Valencia red variety from both Busia and Kisii Central had higher oil content (mean 46.9), than other varieties. In addition, Valencia red from Busia district had slightly higher oil content (47.2%) than those of the same variety from Kisii Central (46.6%). However, the difference was not significant (t=1.08, df=6, P=0.394). Overall, oil content in peanuts decreased with an increase in aflatoxin levels (r=-0.496, P=0.031) except in peanuts of Uganda local red variety from Kisii Central. Growing of improved varieties of peanuts such as Valencia red which was least contaminated with aflatoxin and had higher oil content should be encouraged in Kenya