LOS ANGELES—Another proposed class-action lawsuit questions whether a food company has misrepresented that its products are "all natural".

The latest victim: H.J. Heinz Company, the ketchup king.

A California woman, Debbie Banafsheha, has sued Heinz, contending its distilled white vinegar is not "all natural" because the product is made with genetically modified crops, namely corn. Banafsheha alleged Heinz has violated the Consumer Legal Remedies Act, the California Unfair Competition Law, the California False Advertising Law and breached an express warranty.

The Pittsburg company sells Heinz Distilled White Vinegar for between $1.13 (16 fluid ounce size) and $3.83 (1.32 gallon size), according to the March 17 lawsuit.  

“While Heinz does not comment on pending litigation, we believe this to be a groundless lawsuit and we look forward to vigorously defending our products," said Michael Mullen, Heinz senior vice president of corporate and government affairs.   

The 14-page lawsuit, filed in the U.S. District Court for the Central District of California by the law firm Adhoot & Wolfson, P.C., is just one of many complaints that question the truthfulness of the term "all natural".

A number of "all natural" lawsuits have resulted in settlements and court dismissals, and the stakes become much higher if and once a large class of consumers is certified because the damages can be worth millions of dollars, food lawyers have said.

Early this year, the U.S. Food and Drug Administration (FDA) declined to decide whether food may be labeled "Natural", "All Natural" or "100% Natural" if its contains bioengineered ingredients, putting the onus on the federal district courts in litigation that has sprung up across the United States. FDA has not formally defined the term "natural", and its current policy does not address whether food may be labeled natural if its contains GMOs.