Occurrence of Aflatoxigenic Aspergillus Species in Various Varieties of Peanuts Produced in Western Kenya
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Date
2017
Authors
Menza, Nelson C.
Muturi, Margaret W.
Kamau, Lucy
Journal Title
Journal ISSN
Volume Title
Publisher
PrePrints
Abstract
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
Description
DOI:10.20944/preprints201701.0044.v1
Keywords
Aflatoxins, Peanuts, Aspergillus species