State and local public health officials in Minnesota investigated an outbreak of Salmonella Enteritidis infections among patrons of a restaurant located in Osseo. Six outbreak cases were identified, including 5 cases that were identified through routine surveillance. Two cases were hospitalized. No one died. Meal dates reported by cases were February 12, 13, 22, 23 (n=2), and 26. Cases consumed a variety of items from the breakfast, lunch, and dinner menus. Due to the small number of cases for each individual implicated meal date and large range of dates, a meaningful analysis could not be performed to determine the cause of the outbreak.

All 32 employees were interviewed. Five (16%) reported recent gastrointestinal illness. All employees submitted two stool specimens to the Minnesota Department of Health Public Health Laboratory. Six employees were positive for S. Enteritidis. Four of the 6 Salmonella-positive employees were asymptomatic. Illness onset dates for the two Salmonella-positive employees that were ill were February 27 and March 2.

Isolates from five laboratory-confirmed patron cases and the six food worker cases were indistinguishable by PFGE and were closely related (within 0-2 single nucleotide polymorphisms) by WGS.

During the environmental health assessment, Hennepin County Environmental Health sanitarians noted improper storage of food in the walk-in cooler (shell eggs stored over ready-to-eat foods), deficiencies in thermometer use, and employee illnesses that were not recorded in the illness log. The facility was par-cooking chicken breast prior to service to shorten cooking time. The par-cooked chicken breasts were not being temped correctly and were being stored as a ready to eat produce.

A definitive vehicle and route of transmission were not identified although it is possible that the outbreak was caused by an ill food handler or cross-contamination.