Mycotoxin in Wine

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Mycotoxin in wine from ACS's Chemical & Engineering News.

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Chemical & Engineering News, March 22, 2010, Volume 88, Number 12 p. 44

Wine's Mycotoxin Profile Grows , Another fungal toxin associated with

grains is present in wines worldwide

K.

As they raise a glass, most wine drinkers would prefer to ponder the

ancient beverage’s possible health benefits—lowering cholesterol,

improving heart health—rather than its possible contamination with

carcinogenic, kidney-destroying fungal toxins.

But dangerous mycotoxins produced by fungus species are found in wine.

Mycotoxins are longtime contaminants as old as food itself. Multitudes

of toxin-producing fungi invade grains, peanuts, coffee, grapes, and

other foods. Wine, by association with grapes, is not immune: It can

contain small amounts of aflatoxins, which are carcinogens most

notoriously associated with peanuts, and ochratoxin A, found in

decaying fruits. Allowable amounts of these toxins in foods are

heavily regulated by the U.S. and European governments.

Now, chemists have discovered that yet another mycotoxin, known as

fumonisin B2, once thought to be mainly a problem in grains, also

exists in wine (J. Agric. Food. Chem., DOI: 10.1021/jf904520t).

Kristian F. Nielsen, who heads the analytical facilities lab at the

Center for Microbial Biotechnology at the Technical University of

Denmark, and his colleagues O. Larsen and Jesper M. Mogensen

used an augmented analytical technique to discover that 23% of 77

wines they tested contain fumonisin B2.

Before you throw out your bottles of Châteauneuf du Pape, consider

that as with many foods, levels of these toxins are quite low, well

below government standards set in most countries. But the new work

suggests a need for further study of fumonisins in wine, the

researchers say.

The family of fumonisins, which are toxic to the liver and kidneys in

animals, were discovered in the late 1980s. They’re produced by

Fusarium molds, which thrive on grain products. Since their discovery,

the U.S. Food & Drug Administration and the European Economic

Community have set limits for concentrations in foods.

“Until 2007, we did not think that any fungi growing on grapes could

produce fumonisins,†Nielsen says. “Thus there was no reason to search

for them.†But only three years ago, scientists discovered that a

non-Fusarium fruit-loving fungus, Aspergillis niger, can also produce

fumonisins B2, B4, and B8 (J. Agric. Food. Chem. 2007, 55, 9727).

Because this fungus preys on fruit, scientists began looking for

traces of fumonisins in crops such as grapes.

In the past year, several groups around the world, including

Nielsen’s, have detected fumonisins in grapes, raisins, and must. It

was then a short leap from grapes to wine. Because wine contains a

plethora of potentially confounding compounds, such as tannins and

anthocyanins, Nielsen’s group developed a cation-exchange method to

purify samples before subjecting them to chromatographic and mass

spectrometric studies.

They put to the test 77 different wines from all over the world,

including red and white varieties and vintages ranging from 1991 to

2008. Eighteen of the wines contained some fumonisin B2, some with

only 1 μg/L. Sorry, Californians: The wine with the highest level of

fumonisin B2 was a 1998 California Zinfandel, with 25 μg/L. But the

group found no correlation with year, variety, or location.

M. Maragos, who studies fumonisins at the U.S. Department of

Agriculture’s Agricultural Research Service in Peoria, Ill., notes

that “the highest level found in the wine (25 μg of fumonisin B2 per

liter) is still only about 1% of the guidance level for fumonisins in

maize.†The guidance level in maize was reached with significant

scientific input, as well as with public comment, he adds, “so it does

represent a reasonable value given what we know about the toxicity and

prevalence of the fumonisins.â€

The effect of the discovery on the wine industry and the response of

regulatory agencies are yet to be determined. Norma R. Hill, chief of

the Tobacco Tax & Trade Bureau’s Compliance Monitoring Laboratory, in

Walnut Creek, Calif., whose group has studied mycotoxins in alcoholic

beverages, declined to comment on the issue as this article was going

to press.

Chemical & Engineering News ISSN 0009-234 Copyright © 2010 American

Chemical Society