OAKLAND, Calif.A federal judge on Thursday punted to federal regulators a question that has plagued U.S. food companies. Is it lawful to label foods "natural" when they contain ingredients whose genes have been modified?

In a proposed class action lawsuit filed against the tortilla giant Gruma Corp., U.S. District Judge Yvonne Gonzales Rogers referred to FDA "the question of whether and under what circumstances food products containing ingredients produced using bioengineered seed may or may not be labeled 'Natural' or 'All Natural' or '100% Natural'". She also put a stay on the case for six months.

Benjamin Lopatin, a San Francisco-based attorney representing the proposed class, declined to comment when asked if he planned to file a request for reconsideration or appeal the ruling.  

Gruma is defending a proposed class action over the labeling of its tortilla products. Lawyers for the proposed class contend labels on its food products are false and misleading because they contain GMOs (genetically modified organisms), namely corn that is grown from genetically-modified seeds.

Whether FDA will answer the legal question is uncertain.

Three years ago, in a lawsuit filed against Hornell Brewing Co., a federal judge stayed the case for six months, referring to FDA the question of whether high fructose corn syrup qualifies as a "natural" ingredient. But the agency's Center for Food Safety and Applied Nutrition (CFSAN) declined to make the determination, citing higher priorities and the years it would take to undertake such a proceeding.

"I don't think a lot of people are holding out hope this [case, Elizabeth Cox v. Gruma Corp.] is going to be different than the other one," an attorney representing food companies said before the ruling.

Rogers said FDA has defined the term natural on food labels in non-binding draft guidance.  

"However, the parties appear to be in agreement that the FDA has not addressed, even informally, the question of whether foods containing GMO or bioengineered ingredients may be labeled 'natural' or 'all natural,' or whether GMO or bioengineered ingredients would be considered 'artificial or synthetic,'" she wrote.

When asked to comment on whether it had plans to address the legal issue the judge referred to FDA, a spokesperson for the agency said, "FDA is reviewing the order at this time."