Two U.S. residents, one from New Hampshire and another from upstate New York, have died after eating ground beef that may be responsible for an E. coli outbreak linked to illness in more than two dozen people.

The suspect beef was produced by a company in western New York State, Fairbank Farms, which issued a voluntary recall Saturday for 545,699 pounds of ground beef products.

The products in question are ground beef or packaged beef patties that were made from Sept. 14 to Sept. 16 and distributed mostly in the Northeast. All are stamped “EST 492,” either within the Department of Agriculture’s mark of inspection or near the nutrition facts.

The products went to retailers in eight states: Connecticut, Maryland, Massachusetts, New Jersey, New York, North Carolina, Pennsylvania and Virginia. The stores receiving them included Trader Joe’s, Giant, Price Chopper, Wild Harvest and Shaw’s.

Agnes Schafer, a spokeswoman for Fairbank Farms, based in Ashville, New York, noted that no tests had yet proved conclusively that the company’s products were the source of the bacterial outbreak, to which public health investigators have linked the illnesses of at least 28 people.

Schafer also said all the recalled products were 23 to 32 days past their sell-by dates as of Monday, and so none should still be on grocery store shelves.

But Beth Daly, an epidemiologist with the New Hampshire Department of Health and Human Services, said there is still some danger. “We’re more concerned that people have this product in their freezer and might still be eating it,” said Daly.

Infection with E. coli O157:H7 can have a wide range of effects, from mild intestinal discomfort to death. The New Hampshire resident who died of it contracted hemolytic uremic syndrome, a disease that attacks red blood cells and can cause kidney failure.

The New Yorker who died was an adult from Albany County who had several underlying health problems, the Associated Press reported.

While thorough cooking can kill E. coli O157:H7, it is dangerous even in microscopic doses and can be spread from utensils or cooking surfaces to other foods.

Donna Rosenbaum, executive director of Safe Tables Our Priority, a food safety organization, said the Fairbank Farms recall, and a smaller beef recall on Oct. 26 in Massachusetts by Crocetti’s Oakdale Packing Company, showed that the nation’s food inspection system needed reform.

“To this day,” she said, “contamination problems are not found by any checks on the products by companies. They’re found when people get sick, and that’s a failure in the system.”