ST. PAUL (AP) — The first known U.S. outbreak linked to a rare strain of E. coli in ground beef is prompting a fresh look at tougher regulations to protect the nation’s meat supply.

Three people in Maine and New York became ill this summer after eating ground beef traced back to a Cargill plant in Wyalusing, Pa. Cargill Meat Solutions, a subsidiary of Minneapolis-based Cargill Inc., recalled about 8,500 pounds of ground beef on Saturday, and regulators warned consumers to throw out frozen meat purchased at BJ’s Wholesale Clubs in eight eastern states. The ground beef had a use-by-or-freeze-by date of July 1.

Dr. Elisabeth Hagen, who was appointed undersecretary of food safety at the U.S. Department of Agriculture nine days before the recall, has signaled interest in expanding federal oversight of meat beyond the most prevalent strain of E. coli.

“In order to best prevent illnesses and deaths from dangerous E. coli in beef, our policies need to evolve to address a broader range of these pathogens,” Hagen said in a statement.

The New York Times first reported the USDA interest in federal oversight of other strains of E. coli following the Cargill recall.