presence of aflatoxins in smoked-dried fish sold in abeokuta, ogun ...

A second new species, closely related to A. nomius, was described by Peterson et al. (2001) and
named A. bombycis. These two species were distinguished from each other by differences in
DNA, and also by differences in growth rates at 37 °C. Like A. nomius, A. bombycis produces
both B and G aflatoxins. The species A. ochraceoroseus described by Bartoli et al. (1978) was
recently shown to be another aflatoxin producer. It also produces sterigmatocystin (Klich et al.,
2000). This same isolate was reported by Stubblefield et al. (1970) to produce B but not G
aflatoxins, in line with those assessments. Moreover, Geiser et al. (2000) showed that the
production of small versus large sclerotia does not have taxonomic significance within A. flavus.
Two aflatoxin-producing isolates from Japan, originally classified as aberrant A. tamari (Goto et
al., 1996), were recently described as A. pseudotamarii. Like A. flavus, this species produces B
aflatoxins and CPA, but differs from A. flavus by the production of orange-brown conidia (Ito et
al., 2001).
In studying population genetics of A. flavus, Geiser et al. (2000) showed that A. flavus from an
Australian peanut field comprised two distinct subgroups, which they termed Group I and Group
II, and suggested that Group II differed from Group I sufficiently to be raised to species level.
Further studies by Geiser et al. (2000) and independent observations have confirmed that A.
flavus Group II comprises a distinct species, which will be described as ‘Aspergillus australis’.
Unlike any other known species, A. australis produces both B and G aflatoxins and also CPA.
It appears to occur almost exclusively in the southern hemisphere, where it has been found in
Argentina, Australia, Indonesia and South Africa.
The evidence indicates that A. flavus and A. parasiticus are responsible for the overwhelming
proportion of aflatoxins found in foodstuffs throughout the world. Of the other species, only A.
australis, which appears to be widespread in the southern hemisphere and is common in
Australian peanut soils, may also be an important source of aflatoxins in a few countries.
Results obtained from a study carried out on the level of aflatoxins in smoked-dried fish in three
markets in Uyo town, Akwa-Ibom State showed that Aspergillus flavus, Aspergillus tereus,
A.fumigatus, Absidia sp., Rhizopus sp., Aspergillus niger, Mucor sp. Cladosporum sp.,
Penicillium italicum, Penicilium viridatus, Candida tropicalis and Fusarium moniliformis
were found to be associated with smoked dried fishes sold in different market in Uyo.
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