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[SANET-MG] mycotoxins in food



October 17, 2004
Prof. Joe Cummins
“Mycotoxins in food”
Mycotoxins are toxic metabolites produced by fungi. Mycotoxin poisoning
has been known since the beginning of agriculture and it has caused a
large toll on humans and farm animals consuming food and feed from
contaminated crops. Health effects of mycotoxins include immunological
effects, organ specific damage, cancer and in some cases death.
Agricultural workers may also suffer from dermal and respiratory
exposure during crop harvest and storage. Mycotoxin poisoning is a
worldwide problem effecting maize, rice,, tree nuts and peanuts along
with fresh fruits and vegetables. Many countries regulate specific
mycotoxins and most countries try to limit the toll from exposure to the
toxins (1). Poor rural suffer greater impacts from mycotoxin exposure
than do urban dwellers because the urban food supplies have begun to be
more strictly regulated (2). Recently academic and corporate public
relations have widely disseminated claims to the effect that organic
food and feed is more heavily contaminated with mycotoxins than are
conventional and genetically modified foods because organic production
does not employ synthetic chemical fungicides. However, the Food and
Agriculture Organization (FAO) of the United Nations recently
acknowledged “studies have not shown that consuming organic products
leads to a greater risk of mycotoxin contamination” (3). In the
following discussion the numerous publications support the comment of
FAO and the dearth pf publications showing that organic foods are more
contaminated than conventional foods indicate that the public relations
efforts of academe and corporations condemning organic food are
essentially groundless.
The fungal species Fusarium, Penicillium, Aspergillus and Stachybotrys
are the main producers of toxins. The genes for the biosynthetic
pathways for mycotoxin production are extensive and tend to cluster on a
few fungal chromosomes. The gene clusters will segregate together as a
unit conferring a selective advantage to the fungus. Evolution of the
gene cliusters is through vertical or horizontal gene transfer, in fungi
, horizontal gene transfer is most effective (4). The structure,
synthesis and biosynthesis of mycotoxins such as fumosin have been
extensively analyzed (5). Fuller understanding of mycotoxin genetics and
molecular biology should lead to more effective control measure.
The following discussion provides a number of studies comparing
mycotoxin levels in organic, conventional or GM crops. A number of
exaggerated claims about greatly elevated levels of mycotoxin in organic
foods have begun to appear in the world wide net or in news media. The
peer reviewed publications do not bear out those exaggerated claims.
Ochratoxin is a toxin produced in Penicillium and Aspergillus fungi. It
is mainly found in grain, nuts and dried fruits and usually is
associated with storage of such foods. The toxin causes renal and kidney
toxicity , cancer and immune suppression. Conventional and organic
cereals on the Italian market were studied and no important differences
were found between the two agricultural practices(6). Ochratoxin was
evaluated in cereal baby foods on the Italian market. Here , integrated
pest management, organic and conventional agriculture practices were
compared. Cereals from integrated pest management had no detectable
toxin, conventional practices had elevated toxin levels in multigrain
cereals and seminola based cereal while organic rice based cereal alone
contained toxin. The study concludes there is no significant risk to
children who occassionaly consume toxin contaminated at the observed
levels (7). Ochratoxin has also been observed in the milk of cows
consuming contaminated grain. Norwegian milk and baby formula from
organic and conventional production was compared. No toxin was observed
in any of the infant formulae while toxin was found in 6 out of 40
conventional milk samples and 5 out of 47 organic milk samples, the
highest detected toxin in conventional milk was twice the level of the
highest detected toxin in organic milk (8).
Conventional and organic Italian foodstuffs made up of maize, wheat,
rice or mixed products were studied for Fusarium toxins fumosinins and
deoxynivalenol. Fumosinins cause cancers of liver or kidney along with
blood disorders and pulmonary edema in farm and experimental animals.
Deoxynivalenol. (vomitosin) cause anorexia at low levels and vomiting at
higher levels, it causes damage to the immune system. Both organic and
conventional foods contained the toxins but more of the conventional
foods were contaminated than organic foodstuffs. The highest observed
deoxynivalenol levels were observed in conventional rice based
foodstuffs while the highest level of fumosinins was found in
conventional maize based foodstuffs . Organic foodstuffs contained
consistently lower contamination than did conventional foodstuffs.(9). A
broad study including heavy metals, nitrates and mycotoxins in a range
organic and conventional foods in France showed no significanct
differences between organic and conventional foods in a number of
mycotoxins . One high level of patulin was observed in one sample of
organic apples but no values for patulin content in conventional apples
were reported in the study (10).
Patulin is produced Penicillium and Aspergillus fungi, that toxin is
known to damage genes , cause birth defects and cause immunologic and
neurotoxic effects.The toxin was studied in Italian apple products ,
there was no significant difference between organic and conventional
apple products(11). A report from South Africa indicated that patulin
was present in commercial apple products and noted “organically produced
apple cider, a study done by other researchers has found levels up to
40,000 micrograms per liter” and used that finding to make general
claims about the unsafe practices in organic agriculture (12). In spite
of extensive literature searches I am unable to locate a peer reviewed
report of that huge level of toxin even though that value has been
promulgated through a number of news media and web reports.
Genetic modification (GM) has been promoted as a means of preventing
mycotoxin contamination, particularly in maize. Several strategies have
been proposed but only the use of Bacillus thuringiensis (Bt) toxin to
prevent corn borer tunneling which encourages fungal growth in maize has
been deployed (13). Bt and conventional isogenic maize was studied in
France and Spain. Moderate to low levels of mycotoxins were found on
both GM and conventional maize but significant differences were found in
some areas (14). The presence of mycotoxins in Bt and conventional maize
tested in central Europe concluded that under European conditions the
use of Bt maize will only slightly reduce contamination of maize with
mycotoxins produced by fusarium fungi (15).
Peer reviewed publications indicate that organic foods are not at all
more hazardous sources of mycotoxins than are conventional foods, and
organic foods may , in the main, provide protection from the toxins. The
use of GM maize has not provided major protection from mycotoxins in
comparison to conventional maize. There is a growing sense that the
world of public relations has unleashed a propaganda campaign against
organic food that has little or no basis in scientific fact.
References
1.Barrett,J. Mycotoxins of molds and maladies 2000 Environmental Health
Perspectives 108,A20-AA23
2 Taylor,D. Mold in maize 2001 Environmental Health Perspectives 109,A132
3. Food and Agriculture Organization (FAO) Frequently asked questions on
organic agriculture 2004 pp1-10 http://www.fao.org/organicag/fram11-e.htm
4.Sidhu,G. Mycotoxin genetics and gene clusters 2002 European Journal of
Plant Pathology 108,705-11
5.ApSimon,J. Structure, synthesis and biosynthesis of Fumonsinin B1 and
related compounds 2001 Environmental Health Perspectives Supplement 2
109,254-9
6. Biffi,R,Munari,M,Dioguardi,L,Ballabio,C,Cattaneo,A,Galli,C. and
Restani,P. Ochratoxin A in conventional and organic cereal derivatives:
a survey of the Italian market, 2001–02 2004 Food Additives and
Contaminants 21,586-91
7. Berettay,B., De Domenicoy,R,Gaiaschiy,A,
Ballabioy,C,Galliy,C,Gigliotti,C. and Restaniy,P. Ochratoxin A in
cereal-based baby foods: occurrence and safety evaluation 2002 Food
Additives and Contaminants 19, 70-5
8. Skaug,M. Analysis of Norwegian milk and infant formulas for
ochratoxin A 1999 Food additives and Contaminants 16,75-8
9. Cirillo,T,Ritieni,A,Visone,M. and Cocchieri, R. Evaluation of
Conventional and Organic Italian Foodstuffs for Deoxynivalenol and
Fumonisins B1 and B2 2003 J.Agric. Food Chem. 51,8128-31
10. Malmaurety,L,Parent-Massin,D. and Hardy,J. Contaminants in organic
and conventional foodstuffs in France 2002 Food Additives and
Contaminants 19,524-32
11. Ritieni, A. Patulin in Italian commercial apple products 2003 J.
Agric.Food Chem. 51, 6086-90
12.Theunissen,I. Food for thought 2002 Science in Africa pp1-4
http://www.scienceinafrica.co.za/2002/december/food.htm
13.Duvick,J. Prospects for reducing fumosinin contamination of maize
through genetic modification 2001 Environmental Health perspectives 109
supplement 2 , 337-42
14.Bakan,B,Melcion,D,Richard-Molard,D. and Cahagnier,B. Fungal Growth
and Fusarium Mycotoxin Content in Isogenic Traditional Maize and
Genetically Modified Maize Grown in France and Spain 2002J. Agric. Food
Chem.50,728-31
15. Magg,T,Melchinger,A,Klein,D. and Bohn,M. Relationship betwen
European corn borer resistance and concentration of mycotoxins produced
by Fusarium spp. In grains of transgenic Bt maize hybrids, their
isogenic counterparts, and commercial varieties 2002 Plant Breeding
121,146-56

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