Pet food maker Mars Inc. has been growling at Del Monte Foods Co. for the past few years, claiming its rival infringed on its patent with pet treats such as Snausages Scooby Snack Stuffers and Pounce Delectables.

A U.S. District Court judge in California ruled this week that Mars wasn't just chasing squirrels and Del Monte did put a paw across the line by offering several products that paired hard shells with creamy fillings, much as Mars already did.

A jury trial has been ordered next month to determine whether Mars will get $2.3 million in compensatory damages, plus additional damages for willful infringement and a permanent injunction to stop Del Monte from making the so-called dual-textured products.

"Mars is a leader in this field and developed the dual-textured pet treat that is crunchy on the outside and creamy inside," said Linda Addison, a Houston attorney representing Mars on the case. In addition to the compensatory damages, the plaintiffs are asking for $1 million, although that would be up to the jury. Whatever amount jurors settle on could be trebled by the court.

Del Monte is not rolling over yet. The San Francisco company, in a filing yesterday with the Securities and Exchange Commission, said it would stick with its defense that Mars' patent is invalid and that it did not willfully do anything wrong.

Del Monte also said it did not expect potential damages to have a material effect on its cash flows. The company said net sales of affected products such as Pounce Purr-fections and Meaty Bones Savory Bites should be insignificant in light of the company's total net sales this year.

Del Monte's pet product sales, which include lines unaffected by the lawsuit such as 9Lives and Kibbles 'n Bits, totaled $789 million in the most recent fiscal year. Total company sales exceeded $3 billion.

Del Monte acquired the pet food lines and the lawsuit when it bought several businesses from Pittsburgh ketchup maker H.J. Heinz Co. in 2002. The suit was rejected by one court, then revived through appeal.

Mars' pet food brands include Whiskas, Sheba and Pedigree.