A chemical used to kill weeds could be in your favorite wine or beer.

Trace amounts of glyphosate, the active ingredient in Bayer’s herbicide Roundup, a weed killer, are showing up in wine and beer, according to a new report from the U.S. Public Research Group (USPIRG) Education Fund. The herbicide was owned by Monsanto before the company was purchased by Germany’s Bayer AG.

USPIRG tested 20 products — five wines and 15 beers — and found traces of the carcinogen in 19 of them. The tested wines included Beringer, Barefoot and Sutter Home and the beers included Budweiser BUD, -0.22% , Coors TAP, +0.41% , Miller Lite, Sam Adams SAM, +3.82% , Samuel Smith Organic and New Belgium.

The highest levels of glyphosate were found in St. Helena, California-based Sutter Home wine ($5.99 per bottle), which contained 51 parts per billion, according to the report. The widely available brand is sold at Target TGT, +2.81% , Walmart WMT, +0.90% and convenience stores.

Organic wines and beers contained the chemical

Beringer Founders’ Estate Moscato ($5.99) contained 42.6 ppb; and Barefoot Cabernet Sauvignon ($5.99) contained 36.3 ppb. Conventional beer brands including Coors TAP, +0.41% ($5.79 per six pack); China’s second largest brewery, Tsingtao ($7.89 per six pack); and Miller Lite ($8.99 per six pack) all showed glyphosate levels above 25 ppb.

“ ‘The miniscule trace amounts of glyphosate that may be present in wine from use on vineyard weeds are well within the safe level that the U.S. Environmental Protection Agency has established.’ ” — — Jim Caudill, spokesman for Beringer wines

While glyphosate is not allowed in organic farming, several organic products were contaminated, according to the report, including Samuel Smith Organic Cider ($14.99), which had 3.5 ppb; and Inkarri Estate organic wine ($12.98), which contained 5.2 ppb; and Frey Organic Natural White wine ($9.99), which contained 4.8.

One organic beer brand, Peak Organic IPA ($10.99 per six pack) did not contain any detectable levels of glyphosate, according to the report.

Three of the companies whose beverages were tested responded to requests for comment from MarketWatch. Wine label Beringer acknowledged the potential for herbicides to appear in “trace amounts” in its wine. “Glyphosate is an approved herbicide widely used by farmers around the world,” said Beringer spokesman Jim Caudill. “The miniscule trace amounts of glyphosate that may be present in wine from use on vineyard weeds are well within the safe level that the U.S. Environmental Protection Agency has established.”

A spokesman for Inkarri said the winery had stopped using glyphosate in 2012 when it converted to organic farming methods. But studies show the chemical can linger in the soil for more than 20 years, said Juan Pelizzatti, managing partner at Natural Merchants, the producer of Inkarri. “We do not use glyphosate on any of our vineyards, and strongly support the worldwide ban of glyphosate as we understand it is causing a systemic contamination that is very difficult to control, jeopardizing the freedom of choice and health of the global community,” Pelizzatti said.

A spokesperson for the Beer Institute, a national trade association, told MarketWatch, “Our members work with farmers who go to great lengths to raise their crops sustainably and safely...The results of the most recent federal testing showed farmers’ use of glyphosate falls well below federal limits. As the report itself says, the levels of glyphosate referenced ‘are below EPA risk tolerances for beverages.’”

William Reeves, a toxicologist for Bayer BAYRY, -0.78% , said in a statement that glyphosate does not cause cancer. (Monsanto was acquired by Bayer in 2018.) “The claims about glyphosate harming gut bacteria and stimulating growth of breast cancer cells are also false,” he said. “These claims were evaluated during safety reviews in the U.S. and Europe and found to be unsupported by reliable data.” He cited studies that speak to the safety of glyphosate and Bayer’s own information on the use of the chemical.

He added, “The U.S. Environmental Protection Agency sets daily exposure limits at least 100 times below levels shown to have no negative effect in safety studies. The levels sometimes found in food are not even remotely close to any level of concern. Nothing in the ppb numbers U.S. PIRG is publicizing demonstrate any safety concern associated with the tested products. All levels reported are far below the limits EPA established to protect human health.”

Glyphosate is allowed in food and beverages

A certain amount of glyphosate is allowed in food and beverages under U.S. environmental law, and none of the beers and wines that USPIRG tested contained more than that amount. But that doesn’t mean they’re necessarily completely safe for human consumption, USPIRG noted.

“While these levels of glyphosate are below EPA risk tolerances for beverages, it is possible that even low levels of glyphosate can be problematic,” according to the study. “For example, in one study, scientists found that 1 part per trillion of glyphosate has the potential to stimulate the growth of breast cancer cells and disrupt the endocrine system.”

But a wine lover would have to drink a lot of wine for the herbicide to affect their health, according to one expert. “An adult would have to drink 2,500 glasses of wine a day containing the highest glyphosate level measured every day for 70 years just to reach the U.S. EPA’s preliminary level of health concern,” Carl Winter, professor of food toxicology at the University of California at Davis, is quoted as saying on a blog for the Wine Institute, a wine industry advocacy group.

Glyphosate has been linked to cancer

The World Health Organization has linked glyphosate — widely used by landscapers and farmers around the world and sold for consumer use in residential gardening — to cancer in recent years. It’s worth noting that glyphosate is allowed for use in vineyards, where it is used to destroy weeds. While it’s not sprayed on the grapes or vines, trace amounts of glyphosate can end up in wine from its use on the weeds, according to the Wine Institute.

Last August, glyphosate was found in dozens of popular oat-based breakfast foods like Cheerios Toasted Whole Grain Oat Cereal and Quaker Old Fashioned Oats, according to a report by the nonprofit Environmental Working Group. Makers of the foods EWG tested said they operate within U.S. government safety guidelines and shrugged off the group’s findings. “Our products are safe and without questions they meet regulatory safety levels,” a representative for General Mills told Fox Business at the time.

That same month, a California jury ordered Monsanto to pay $289 million in damages to a man dying of cancer who said being exposed to the pesticide while working as a school grounds keeper caused the disease. Bayer, the owner of Monsanto, denied all allegations that Roundup or glyphosate cause cancer. Bayer said at the time that it would repeal the verdict, Reuters reported.