Aflatoxin and sponges
Aflatoxin kills:
AFLATOXIN KILLS Dick Sieger
Pet food contaminated with aflatoxin killed approximately 100
dogs during the recent holiday season. The product, since recalled,
was manufactured by Diamond Pet Food
and sold in 22 eastern states (see http://
http://www.diamondpetrecall.com). The poisonous
aflatoxin came from corn infected by
the mold Aspergillus flavus. The deaths
resulted from liver failure. Symptoms
included lethargy, poor appetite, yellowish
eyes or gums, internal bleeding, and
severe, perhaps bloody, diarrhea.
Diamond tests each load of corn for
aflatoxin and usually rejects a shipment
weekly. Aspergillus infections, however,
are spotty, and a sample from one part of
a truckload may not reveal contamination
elsewhere.
Aflatoxin is produced by some strains of Aspergillus flavus as
well as the closely related A. parasiticus. Aspergillus flavus survives
in the soil as a mat of mycelium (chains of cells) or a hard mass of
tissue (sclerotium) which produce spore-bearing structures called
conidiophores. Carried by moving air and insects, the asexual
spores (conidia) infect plants before they are harvested and while
they are in storage. Plants stressed by drought and high temperatures
are particularly vulnerable. The fungus grows best on warm,
dry substrates which may appear and smell wholesome.
Aflatoxins have been found in many farm products but are especially
troublesome in ubiquitous foods and feeds such as peanuts
and peanut butter, cottonseed, and corn. Meat, milk, and cheese
may contain aflatoxins when animals eat tainted feed. The toxins
can cause severe liver, kidney, and heart damage. There is no ethical
way to measure the effect of aflatoxins on people, but for some
animals they are the most powerful carcinogen known. Because
of circumstantial evidence, the most common aflatoxin (B1) is
listed as a human carcinogen. It appears that long-term exposure
to even small amounts can endanger people and animals.
Aflatoxins are remarkably resistant to high temperatures. Once in
food, they persist. Fortunately, alkaline processing of the corn used
in tortillas does degrade them.
The FDA considers aflatoxins unavoidable food contaminants and
allows our food to contain as much as 20 parts per billion (0.5 ppb
for milk). Canada has a limit of 15 ppb and Germany 10 ppb. Dr.
Bryce Kendrick, FRSC, a mycologist noted for his work with
molds, writes in the CD-ROM version of his book The Fifth Kingdom
(see
www.mycolog.com/fifthtoc.html), “…my own feeling
is that no detectable aflatoxin should be permitted. If proper
attention was paid to storage and selection of peanuts for human
consumption, and to appropriate dilution of mildly contaminated
nuts, this standard could be easily attained.”
www.psms.org/sporeprints/sp419.pdfskytroll