Jerry Greenfield, co-founder of Ben & Jerry's, and Peter Shumlin, Vermont’s governor, unveiled the Food Fight Fudge Brownie flavor, developed to support the state’s legal defense over its law to require labeling of bioengineered ingredients.

BURLINGTON, VT. — In support of home state Vermont’s G.M.O. labeling law, Ben & Jerry’s is entering the fray with Food Fight Fudge Brownie. Sales of the ice cream flavor, formerly named Chocolate Fudge Brownie, will benefit the state’s legal defense against the Grocery Manufacturers Association, which on June 12 filed a complaint in federal district court in Vermont to overturn the state’s law requiring the labeling of food produced with bioengineered ingredients.

“This is a pretty simple issue,” said Jerry Greenfield, co-founder of Ben & Jerry’s. “Vermonters want the right to know what’s in their food, and apparently a bunch of out of state companies don’t want to tell us.”

Food Fight Fudge Brownie contains chocolate ice cream mixed with fudge brownie pieces. A portion from each sale of the flavor in Ben & Jerry’s Vermont company-owned scoop shops will support Food Fight Fund Vermont through July. The company also is seeking donations on-line at foodfightfundvt.org.

“We’re used to putting dough in ice cream, but renaming Chocolate Fudge Brownie to Food Fight Fudge Brownie will help put some dough in the Food Fight Fund,” Mr. Greenfield said.

Ben & Jerry’s, a subsidiary of Unilever, this year announced plans to re-launch its full line of flavors without bioengineered ingredients. All of its products in Europe already are G.M.O.-free. The ice cream maker also supported I-522, a measure on Washington state ballots last November to require labeling for food and beverage products with bioengineered ingredients.

Under the Vermont law to take effect on July 1, 2016, if food for humans is offered for sale at retail in the state and is produced entirely or partially with genetic engineering, the food must be labeled to indicate that fact. Vermont’s governor, Peter Shumlin, signed bill H.B. 112 into law on May 8.

“Vermont’s mandatory G.M.O. labeling law, Act 120, is a costly and misguided measure that will set the nation on a path toward a 50-state patchwork of G.M.O. labeling policies that do nothing to advance the health and safety of consumers,” the G.M.A. said in a statement released in conjunction with the lawsuit.  “Act 120 exceeds the state’s authority under the United States Constitution and in light of this, G.M.A. has filed a complaint in federal district court in Vermont seeking to enjoin this senseless mandate.”