On July 25, 2024, FCCHD and DPHHS received confirmatory testing results of clinical and food samples verifying ground beef as the vehicle of exposure. Specifically, the source of the outbreak was wagyu beef from one lot number.

All patients reported eating undercooked or made-to-order burgers made with wagyu beef at one of multiple restaurants in Flathead County, Montana: Gunsight Saloon, Hops Downtown Grill, Tamarack Brewing Company, the Lodge at Whitefish Lake, and Harbor Grille. Several other facilities—Flathead Fish, the Crawdad Café, and the Flathead Lake Lodge—received contaminated wagyu beef from the same lot number, but no reported illnesses were associated with these establishments.

The last known date of consumption was July 14, 2024.

Once the source of exposure was preliminarily identified, public health staff worked directly with affected businesses to ensure all remaining wagyu beef from the contaminated lot was removed from use. Samples of the suspected product were sent to the DPHHS Montana Public Health Laboratory for testing, which allowed for laboratory confirmation of the outbreak source.

None of the contaminated beef remains in circulation and all businesses associated with this outbreak have been contacted directly.

FCCHD acknowledged the “incredible cooperation” of all businesses involved in the outbreak investigation.