The U.S. wine industry has entered the world of genetic engineering as some vintners experiment with a strain of yeast designed to eliminate chemicals in red wine that are believed to trigger headaches, including migraines, in some people. Scientific research, much of it conducted at the University of California, Davis, has long played an important role in improving the quality of grapes and wines produced in California and around the world. But genetic modification -- in this case inserting two genes into the DNA of a yeast species -- marks a new threshold for the industry.
As a result, the new biotech yeast is getting a wary reception in a wine industry that sells itself on its artisan reputation and is anxious not to ruffle export markets touchy about genetically modified foods. Experts also say the new yeast alters the flavor of wine. "As an industry, we're definitely interested in research when it comes to genetic engineering. But I don't think we're prepared to look at genetically modified products yet," said Paul Dolan, a winemaker and chairman of the Wine Institute, the California industry's leading advocacy group.
Still, the new yeast offers a promising way around the wine-headache problem. About 13 percent of Americans suffer migraines, according to the National Headache Foundation. Migraine patients are commonly told to avoid red wine, said Marco Vespignani, a naturopathic doctor at the Institute for Restorative Health in Davis.
At least a few wines made with the so-called ML01 yeast already are reaching consumers this year, according to Jason Rodriguez, wine products specialist for American Tartaric Products Inc., the California distributor of the yeast. He declined to identify any specific brands, though, and the wines aren't required to carry a special label.
In Northern California and Europe, where genetically modified foods have sparked controversy and strict regulation, a move to the new yeast could simply be trading one headache for another. The growing of genetically modified crops has been banned by voters or county supervisors in Mendocino, Trinity, Marin and Santa Cruz counties. And in Europe, nearly all foods made with significant amounts of genetically modified ingredients must carry a label. That requirement has driven U.S. food companies to avoid the use of such ingredients in products exported to EU countries. U.S. regulations don't require labels detailing whether a food contains genetically modified ingredients.
Wary of backlash in sensitive export markets, Australia's wine industry -- a key international competitor with California -- in November took an official position against the use of the new genetically modified yeast. On Monday, the Wine Institute, which represents many, but not all, of California's wineries, did the same, issuing a statement declaring "that no genetically modified organisms be used in the production of California wine." The institute, however, does not have the authority to keep wineries from using the new yeast.
California wine exports totaled $625 million in 2005, according to the Wine Institute. Six of 10 California winemakers contacted for this story knew of the new yeast, but none said they were using it. Outside the United States, only Moldova, in Eastern Europe, allows its winemakers to use the new yeast. Regulators in several other winemaking countries are reviewing it. The yeast's manufacturer, Lesaffre Yeast Corp. of Milwaukee, did not return calls seeking comment.
Here's how the ML01 yeast works:
Making red wine from crushed grapes usually involves two fermentation steps. In the first, yeasts convert the sugar in crushed grapes into alcohol. In the second, bacteria transform harsh malic acid into relatively mild lactic acid. Headache-causing chemicals can appear in the second step. If the wrong type of bacteria grow, they produce chemicals called amines. These cause reactions, such as headaches, in some people.
The ML01 yeast is able to perform both the first and the second fermentation steps, meaning that bacteria aren't needed at all. Thus, there's little chance of producing the undesirable amines. To give the ML01 yeast the special ability to perform both types of fermentation, researchers inserted a gene from a bacteria species and a second gene from a wild yeast strain into the DNA of a strain of a commercial wine yeast.
Linda Bisson, a professor of viticulture and enology at UC Davis, said the biggest winemaking change in the use of ML01 is the elimination of bacteria from the fermentation process. The tradeoff: Those bacteria add new flavors and aromas to the wine. She said skilled winemakers can avoid creating the headache-causing amines without sacrificing flavor.
The scientist who developed the ML01 yeast, University of British Columbia Professor Hennie van Vuuren, said wines made with it have fared well in taste tests against wines made from the same grapes using conventional fermentation techniques. "The quality of the wine was found to be higher -- it was more full," he said from his home in British Columbia.
Researchers around the world have developed a variety of other genetically modified yeasts, but ML01 is the first on the market. Grapevines, too, have long been a target for genetic engineering, with researchers hoping to give the plants desirable traits such as resistance to fungus and disease. It likely will be years, however, before genetically modified grapes are grown on a production scale.
Van Vuuren spent 16 years developing ML01. He receives no royalties from its commercial sales, and said his motivation to develop the yeast grew from personal experience: Red wine gave him headaches, and he wanted to change that. "I didn't do it for a big corporation," he said. "I did it because I loved wine."
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