by Marian Segal
Winding down the day with a drink before dinner? Is it scotch or bourbon? Sherry or Chablis? Is the choice of the drink just a matter of taste, or could it be a matter of health?
The latest health issue related to the consumption of alcoholic beverages concerns a chemical called urethane, and, as is often the case with health concerns, the questions are coming in much faster than the answers. Scientists know that urethane, which forms as a byproduct in the manufacture of some alcoholic beverages, can cause cancer in laboratory animals. Its effects in humans, however, are not yet known.
According to Gary Flamm, director of the office of toxicological sciences in FDA's Center for Food Safety and Applied Nutrition, "Urethane is a known carcinogen for several species of animals, and, as such, must be viewed as a potential carcinogen for humans as well. The degree of risk to humans, though, is not known. The current scientific data are simply too limited to assess the risk posed by low levels of the chemical in alcoholic beverages."
Concern in this country over urethane (also called ethyl carbamate) began in November 1985 with news reports that Canadian authorities had detected the chemical in certain wines and distilled spirits. At that time, FDA and the Bureau of Alcohol, Tobacco, and Firearms (ATF) began looking for ways to reduce or eliminate urethane in alcoholic beverages. (FDA and ATF share responsibility for regulating alcoholic beverages -- FDA for their safety and cleanliness, under provisions of the Federal Food, Drug, and Cosmetic Act; ATF for the manufacture and composition specifications under authority of the Federal Alcohol Administration Act. The bureau also regulates the labeling and advertising of these products.)
Since January 1986, the two agencies have sampled about 1,200 alcoholic products for urethane levels. This represents a very small sample, however. Wines and whiskeys must be sampled from both foreign and domestic producers -- a formidable task, considering that there are more than 1,000 wineries in the United States alone. ATF estimates there may be as many as 400,000 differently labeled alcoholic beverages in the marketplace.
Among the more widely marketed distilled spirits tested by the agencies (and by industry), bourbons generally contained the highest levels of urethane. Many bourbons contained up to several hundred parts per billion (ppb). According to Curtis Coker of the division of regulatory guidance in the Center for Food Safety and Applied Nutrition, "It appears that the distillation conditions, such as temperature. needed to produce the characteristic flavor of bourbons result in levels of urethane significantly higher than those found in some other distilled spirits, such as vodka, which are distilled under significantly different conditions." Vodka and gin have shown negligible amounts, if any, of urethane. Levels of the chemical in plum and cherry brandies varied from 200 to 12,000 ppb; dessert wines, such as cream sherries, contained from less than 4 ppb to several hundred ppb; and table wines had levels generally from zero to 25 ppb.
Urethane is not an intentionally added substance. It forms during fermentation of alcoholic beverages, and, if the fermented product is heated, such as in "baking" sherry or distilling spirits, its levels increase. Therefore, urethane is to some extent unavoidable in these drinks.
Levels of urethane may be affected not only by temperature, but by other conditions as well, including the type of soil and fertilizer used to grow the raw products, such as grapes, the type of grape used in wine making, and even by the weather. These conditions may cause significant differences in the level of urethane even from one production lot to another of the same brand. After production, levels can still be increased substantially in some products --particularly wines -- by shipping, storage, and handling practices.
Some factors influencing urethane production in alcoholic beverages, such as the weather, are beyond human control. Others, however, can be modified. For instance, some wine makers used to add a substance called urea to stimulate fermentation. However, when urea combines with the alcohol produced during fermentation, it can produce urethane. Now all the major U.S. wineries that had used urea have eliminated it from the manufacturing process. Similarly, manufacturers are experimenting with different baking conditions for sherry to try to reduce levels of urethane. (Sherry is baked to enhance its flavor.) And bourbon manufacturers have found that modifying the distillation process can result in lower levels of urethane by removing more of the chemical during distillation.
Early on, FDA and ATF had several meetings with industry groups to chart a course for determining the sources of urethane in alcoholic beverages and instituting measures aimed at lowering its levels as much as possible. The Center for Science in the Public Interest took exception to this approach. In November 1986, the Washington, D.C. based consumer advocacy group petitioned FDA to recall "highly ¬urethane| contaminated products," systematically test all wines and liquors, publicize all urethane test results, and set limits on allowable urethane levels in new products. In a publication by the group titled Tainted Booze, the group criticized FDA for not establishing limits, and noted that Canada, in December 1985, set regulatory limits for table wines -- 30 ppb; ports and sherries -- 100 ppb; distilled spirits -- 150 ppb; and fruit brandies, cordials and liqueurs -- 400 ppb.
In December 1987 FDA accepted a plan of the Distilled Spirits Council of the United States, Inc., to reduce the levels of urethane in whiskey to 125 ppb or less, starting with all new production Jan. 1, 1989. The Kentucky Distillers Association, Frankfort, Ky., also joined in the agreement. Together, members of the two trade groups market almost all the whiskey sold in the nation.
In January 1988, FDA also accepted a urethane reduction plan for table and dessert wines from the major U.S. wine producers, represented by the Wine Institute and the Association of American Vintners. The plan calls for urethane levels to average no more than 15 ppb in table wines (wines containing 14 percent or less alcohol by volume), starting with wines produced from the 1988 harvest. For dessert wines -- such as cream sherries -- which contain more than 14 percent alcohol, urethane levels are to average no more than 60 ppb, starting with wines produced from the 1989 harvest. The wine associations have also set a goal that, beginning with the 1995 harvest, no more than I percent of table wines will have urethane levels exceeding 25 ppb, and no more than 1 percent of dessert wines will have levels over 90 ppb.
Covered by this agreement are the 530 California wineries represented by the Wine Institute (producers of about 90 percent of domestic wines) and wine producers in 29 states represented by the American Association of Vintners.
FDA and ATF are also working with foreign countries, including Japan, France, Germany, and Switzerland, to reduce the urethane levels in the alcoholic beverages exported to the United States by those countries. Under provisions of the Food, Drug, and Cosmetic Act, FDA must limit the amount of harmful contaminants in foods to the extent that is "necessary for the protection of public health." At the same time, any regulatory limit must take into account the extent to which the substance cannot be avoided in the production of the food. Manufacturers have an obligation to make whatever changes are technologically feasible to reduce or eliminate the amount of the harmful substance
Richard Ronk, acting director of the Center for Food Safety and Applied Nutrition, notes that "FDA is concerned about urethane, but the extent of the risk to consumers is not clear. Until we have more information on the toxicity of the chemical and how much of it can be avoided in the manufacture of alcoholic beverages, it would be inappropriate to establish regulatory limits or to recall alcoholic products." As a law enforcement agency, FDA has to be in a position to defend its enforcement actions, and is currently seeking the scientific data that would permit it to make reliable estimates of the risk to humans, if any, of urethane in alcoholic beverages.
At FDA's request, the National Toxicology Program, a federal research program jointly funded by various federal agencies, agreed to give urethane its highest priority for study in 1988. This research, to be completed in the next few years, is expected to yield the toxicological information needed to accurately assess the risk posed by urethane in alcoholic beverages.
Meanwhile, the wine and the distilled spirits industries will continue their research and sampling of products, and FDA and ATF will continue to monitor industry progress in reducing urethane levels.
Marian Segal is a member of FDA's public affairs staff
FDA Consumer / April 1988 / pp 16-17
Hypertext by frf on 1998-JAN-29