WASHINGTON – Federal inspectors found the strain of salmonella behind a recent food-poisoning outbreak at the ConAgra Foods Inc. plant that made the tainted peanut butter, the Food and Drug Administration said Thursday.

Beyond the Sylvester, Ga., plant, the strain also has been isolated from open jars of the company’s peanut butter and some of the 370 people who have fallen ill in the outbreak, the FDA said.

On Thursday, the FDA said the company had sent bulk Peter Pan peanut butter to its plant in Humboldt, Tenn. There, it was incorporated into various ice cream, sundae and shake toppings. Health officials warned the public to discard the products, which have been recalled.

The products are:

. Sonic Brand Ready-To-Use Peanut Butter Topping in 6 lb. 10.5 oz cans. Sonic outlets used the topping until Feb. 16, when the product was recalled. The topping was used in Sonic’s peanut butter shakes, peanut butter fudge shakes, peanut butter sundaes and peanut butter fudge sundaes, the FDA said.

. Carvel Peanut Butter Topping in 6 lb. 10 oz. cans. Carvel also used the topping until Feb. 16, when it, too, was recalled. The topping was used in Carvel’s Chocolate Peanut Butter, Peanut Butter Treasure, Peanut Butter & Jelly and Reese’s Peanut Butter Cup Sundae Dasher ice cream products, the FDA said. The topping also was used in customized products, like the peanut butter-flavored ice cream in Carvel’s ice cream cakes, the agency added.