By Erin Geiger Smith

Jan 16 (Reuters) - A battle for snack supremacy isn't being fought over who makes the best shortbread cookies, but instead over the packaging they come in.

Kraft Foods Global Brands LLC, a subsidiary of Mondelez International, sued Kellogg Co's North American unit on Wednesday claiming the food maker improperly uses one of its patents to keep Keebler and Sandies cookies fresh.

The Kellogg cookies are packaged in a re-sealable food packaging design that the Kraft maintains is too much like their design, "Snack 'n Seal," according to the lawsuit filed in U.S. District Court in Chicago.

Keebler Company, which is owned by Kellogg, is also named as a defendant in the lawsuit.

Kellogg did not immediately respond to a request for comment.

Michael Mitchell, a spokesman for Mondelez, declined to comment.

Kraft Foods Global Brands, the intellectual property holding company for Mondelez, is seeking damages as well as a permanent injunction barring Kellogg from infringing the patent.

Mondelez, which sells Nutter Butter and Chips Ahoy cookies, is the snack company that remains of Kraft Foods Inc following the October spin-off of its North American grocery business into Kraft Foods Group Inc.

This is not the only food container lawsuit currently pending in the Chicago federal court.

In August 2012, an inventor sued H.J. Heinz Company claiming the ketchup company's "Dip & Squeeze" product violated a patent that he holds on packaging that allows consumers to choose between dipping or squeezing condiments onto foods.

Heinz has denied the allegations.

The Global Brands case is: Kraft Foods Global Brands LLC v. Kellogg North America Company, et al, U.S. District Court for the Northern District of Illinois, No. 13-00321.

For Kraft Foods Global Brands: Jacob Koering of Freeborn & Peters.

For Kellogg: Not immediately available

Follow us on Twitter @ReutersLegal | Like us on Facebook