TITLE:
Occurrence of Aspergillus Species and Aflatoxin Contamination in Raw and Roasted Peanuts from Formal and Informal Markets in Eldoret and Kericho Towns, Kenya
AUTHORS:
Helene Nyirahakizimana, Lizzy Mwamburi, Johnstone Wakhisi, Charity Kawira Mutegi, Maria Elisa Christie, John Maina Wagacha
KEYWORDS:
Aflatoxin; Aspergillus Section Flavi; Peanuts; Peanut Market Outlets
JOURNAL NAME:
Advances in Microbiology,
Vol.3 No.4,
July
18,
2013
ABSTRACT: The population
and diversity of fungal species and levels of aflatoxin contamination
were investigated in 228 marketed peanut samples; 140 from formal and 88 from
informal markets, in Kericho and Eldoret towns of Kenya. Ground peanut samples were cultured on Modified Dichloran Rose
Bengal (MDRB) agar while aflatoxin
level was quantified based on indirect competitive ELISA. Correlation between
the incidence of major aflatoxin-producing fungal species and aflatoxin levels
was also established. Fungal species commonly isolated from the peanut samples included Aspergillus flavus L strain, A. flavus S strain, A. parasiticus, A. tamarii, A. caelatus, A. alliaceus (all of Aspergillus section Flavi) and A. niger. Fungi
isolated in low frequency included Fusarium spp., Penicillium spp., Mucor spp. and Rhizopus spp. Aflatoxin levels in peanut products ranged from 0 to
2345 μg/kg in raw peanuts, 0 to
382 μg/kg in roasted coated peanuts, and 0 to 201 μg/kg in roasted de-coated peanuts. Overall, levels of total aflatoxin were higher in samples from informal
(mean = 97.1 μg/kg) than formal (mean = 55.5 μg/kg) market outlets. There was a
positive and significant correlation (R2 = 0.63; p ≤ 0.05) between aflatoxin levels and
the major aflatoxin producing fungi in raw peanuts from formal markets in
Eldoret town. Additionally, total aflatoxin in raw peanut samples from informal
markets in Kericho was positively and significantly correlated (R2 =
0.81; p ≤ 0.05) to the
population of A. flavus (L and S
strains). In roasted coated peanuts sampled from formal market outlets in
Eldoret, aflatoxin levels correlated positively and significantly (R2 = 0.37; p ≤ 0.05) with A. flavus S strain. There is need to
create awareness among peanut traders and consumers on proper handling of
peanuts and health risks associated with consumption of unsafe peanut products.