Biomedical Engineering Reference
In-Depth Information
Aspergillus
spp.
Aspergillus
species are common storage fungi that infest a wide range
of agricultural products. They cause causes serious disease in humans
and animals. The most common pathogenic and toxigenic species
are
Aspergillus fl avus
,
A. ochraceous
and
A. fumigatus
. Majority of
A.
fl avus
strains produce afl atoxins, which are carcinogenic in nature and
induce liver cancer in laboratory animals.
A. fl avus
var.
fl avus, A. fl avus
subsp.
parasiticus
and
A. nomius
share the ability to produce afl atoxins.
A.
fl avus
growth and afl atoxin biosynthesis depend on substrate, moisture,
temperature, pH, aeration and competing microfl ora. The growth of
A.
fl avus
and afl atoxin production are sometimes unavoidable.
A. fl avus
and
the closely related sub species
parasiticus
have long been recognized as
major contaminants of organic and nonorganic items. Afl atoxins are
considered natural contaminants.
A. fl avus
,
A. parasiticus
,
A. niger
and
A.
ochraceus
have been reported earlier by Reddy et al. (2005) and of which
A. fl avus
have been identifi ed as the primary quality deterrent, producing
afl atoxin-contaminated seeds (Reddy et al. 2005). Reddy (2008), explored
the incidence of
Aspergillus
spp., in 1,200 rice samples consisting of paddy
(675) and milled rice (525) collected from 43 locations in 20 rice-growing
states across India.
Penicillium
spp.
Penicillium
spp., are
mold forming fungi that grow on stored feed, growing
plants, crops and damp indoor spaces. Some produce antibiotics, some
can be opportunistic pathogens and some produce mycotoxins, including
patulin and rubratoxin. Toxins produced by
Penicillium
species are
reported in maize silage and have been associated with health problems
in cattle. Species included in some of these taxa are diffi cult to distinguish
from each other and molecular methods are usually necessary to identify
them. For some of them, taxonomy is not fully resolved, as the number
of accepted species depends on the methodology used. In part for these
reasons, a larger number of species have been cited incorrectly as OTA
producers.
Penicilliumm roqueforti
and
Penicillium carneum
are two other
common and well-characterized species which are known to produce
the mycotoxins roquefortine C and mycophenolic acid, in addition to
PR-toxin (
P. roqueforti
) and patulin (
P. carneum
) (Frisvad and Filtenborg
1989). Other important mycotoxin-producing
Penicillium
species are:
Penicillium
aurantiogriseum
(penitrem A, penicillic acid, mycophenolic acid,
xanthomegnin and viomellein),
Penicillium chrysogenum
(roquefortine C
and cyclopiazonic acid),
Penicillium expansum
(roquefortine C, patulin,
citrinin and chaetoglobosins),
Penicillium griseofulvum
(roquefortine C,
patulin and griseofulvin),
Penicillium viridicatum
(cyclopiazonic acid,
