A federal judge has ruled that a Kern County grape grower can be held jointly responsible for alleged wage-and-hour violations by its outside labor contractors.

Last week's rare but not precedent-setting judgment against Delano Farms Co. could affect how closely Central Valley growers monitor their labor contractors, which are often seen as independent of the companies that hire them to provide farmworker help.

Bakersfield lawyer Mario Martinez, who represents a plaintiff in the class-action case, said, "I think it's important that growers understand that they can't just use the farm labor contractors to just exploit workers."

Organizations representing California grape growers declined to discuss the ruling's implications or could not be reached for comment Thursday. But Delano Farms, part of Washington state-based Anderson & Middleton Co., issued a statement Thursday saying it was disappointed in the decision by Sacramento federal court Judge Lawrence O'Neill.

"We maintain Delano Farms should not be party to this action since the plaintiffs are employees of our contractor, an independent business that retains full control over its operations and its relationship with its employees," the statement reads.

"We value the workers who help to bring our outstanding products to the marketplace."

There has been no ruling yet as to whether any violations were committed in the case. Martinez said a decision favoring the plaintiffs could result in an award of more than $100 million in back pay and damages for some 26,000 farmworkers who worked on Delano Farms property between 2005 and 2009.

The lawsuit alleges that Delano Farms' labor contractors, T&R Bangi's Agricultural Services Inc. and Cal-Pacific Farm Management LP, forced farmworkers to perform unpaid work before and after their shifts, and required them to buy their own tools for the job.

The labor contractors' Hanford attorney, Michael Richard Johnson, denied the charges.

"The allegations are absolutely false," he said. "The farm labor contractor provided tools and only asked people to work during their assigned work times." He declined to elaborate.