LOS ANGELES — Sugar cane and sugar beet growers have attempted to make member companies of the Corn Refiners Association again part of a lawsuit that claims a C.R.A. campaign for high-fructose corn syrup is false and misleading. An amended complaint filed Nov. 18 in a U.S. district court in Los Angeles claims member companies of the C.R.A. conspired to exercise their collective right and actual power to control the C.R.A. as their agent.

“This litigation is about false advertising funded by the C.R.A.’s biggest members,” said Adam Fox of Squire Sanders, lead attorney for the sugar growers.

Audrae Erickson, president of Washington-based C.R.A., said, “The simple truth is that the sugar industry is attempting to use the courts to stifle free speech, but it lacks the facts to support its claims against our member companies. The court made that fact clear in its last ruling, and we continue to believe these claims against the companies should be dismissed.”

The lawsuit originally was filed April 22 by the Western Sugar Cooperative in Colorado, Michigan Sugar Co. and C&G Sugar Co. The lawsuit claims a marketing campaign for HFCS is false and misleading in stating that HFCS is corn sugar. Defendants in the case originally were the C.R.A. and C.R.A. member companies Archer Daniels Midland Co., Cargill, Corn Products International, Inc., Penford Products Co., Roquette America, Inc., and Tate & Lyle Ingredients Americas, Inc.

The court on Oct. 21 denied a motion from the C.R.A. to dismiss the lawsuit, but the court also ruled the plaintiffs’ allegations do not establish a false advertising claim against the individual member companies of the C.R.A.

The amended complaint filed Nov. 18 said other member companies have endorsed and ratified the messaging of the advertising campaign in direct communication to customers. The amended complaint said member companies either used regular meetings of the C.R.A. board of directors or separate meetings conducted during the same period of time to make plans to authorize, develop and fund an advertising campaign. The campaign was designed to promote HFCS as natural, assert HFCS and sugar are equivalent and rebrand HFCS as corn sugar.