FILE PHOTO: The building of the U.S. Supreme Court in Washington, U.S., June 26, 2017. REUTERS/Yuri Gripas/File Photo

WASHINGTON (Reuters) - The U.S. Supreme Court on Tuesday refused to hear a bid by Conagra Brands Inc CAG.N to escape a class-action lawsuit accusing it of falsely labeling its cooking oil as 100 percent natural even though it had genetically modified ingredients.

Conagra had asked to the justices to hear its appeal of a lower court ruling allowing the suit to proceed despite difficulties in determining who should be included and excluded in the litigation, a problem often encountered in disputes over low-cost products.

In 2015, a federal judge in California let purchasers of Wesson brand oil in 11 U.S. states proceed with their claims in a consolidated case, rejecting Conagra’s argument that there was no reliable way to identify those who had bought the oil over the last decade. The 9th U.S. Circuit Court of Appeals in San Francisco upheld that ruling in January, and the company appealed to the Supreme Court.

The purchasers, including lead plaintiff Robert Briseno, a California resident who sued Conagra in 2011, allege the Chicago-based packaged food maker used deceptive labeling dating back to 2007, calling the cooking oil “100% Natural” despite its GMO content, banking on consumers’ willingness to pay more for natural products.

Conagra said that the U.S. Food and Drug Administration has not defined the term “natural” and that it means different things to different people.

The company, supported by the U.S. Chamber of Commerce and the National Association of Manufacturers business groups, argued that consumers rarely save every receipt and cannot typically recall trivial purchases from years ago. Manufacturers, distributors and retailers generally do not keep such records either, it said.

The plaintiffs told the Supreme Court that companies like Conagra simply want to place class actions out of reach for low-priced consumer goods, which individuals are unlikely to sue over on their own. Their motive is to “enable companies to commit wide-scale, but low value, harm to individual consumers with impunity,” they told the justices in a legal brief.