Incident Summary (i.e., define and describe the size, scope, and distribution of the incident):
On 7/17/24 Epi and FPP were notified by a local hospital ED provider of several reports of GI illness following consumption of food from a Brazilian-style restaurant. Since the initial notification, additional cases continued to be identified over the coming 2 weeks, ultimately resulting in 35 confirmed and 17 probable Salmonella cases among patrons (36% hospitalization), and 1 confirmed case among restaurant employees.
The majority of cases reported a consumption date of Sunday 7/14 (n=40) with exposures ranging from 7/12 to 7/19). Most cases reported a symptom onset of Monday 7/15 (range 7/13 to 7/20). Cases reported various exposure settings including in-restaurant dining, self-service takeout, and delivery directly from the restaurant. The local health department obtained a list of buffet items served on Sunday 7/14 from the restaurant that was used to interview or re-interview cases in order to collect detailed food histories. Additionally, Epi requested and received a line list of individuals who received delivery from the restaurant on Sunday 7/14 to help identify controls for a case-control study. The restaurant-specific meal items were incorporated into MAVEN disease events for both cases and controls using a Dynamic question package. This ultimately resulted in re-interviews (completed or attempts) of 62 individuals (cases and controls) conducted by PHNs, Regional Epis, and DPH Epis. Epi conducted a case-control analysis of menu items served on 7/14 that included 35 cases and 13 controls. Chicken Salad (Salpicao) was determined to have an Odds Ratio of 48.0. This finding was determined to be statistically significant indicating that chicken salad (Salpicao) was the likely cause of illness among patrons at the restaurant.
The local health department conducted three inspections (7/18/24, 7/19/24, 7/22/24) and throughout the inspections identified 16 critical violations including improper hot/cold holding temps, improper cleaning techniques, and sanitizer out of the proper concentration range. The LBOH observed 60 pounds of cooked chicken that was at a temperature of 71F degrees and had been cooling for 24 hours in the freezer. The out of temperature chicken was voluntarily discarded. A NEARS form was completed on 7/24/24.
The ingredients in the chicken salad include chicken tenders, fully cooked deli ham, diced carrots (raw), frozen pea/corn/carrot mix, raisins, mayonnaise, whole green olives with pepper, potato sticks, and chicken base. The shredded chicken used in the implicated chicken salad (Salpicao) dish was prepared by boiling raw chicken tenders (80 pounds) in a large pot with 6 gallons of water and stirring the chicken occasionally. The chicken was considered to be cooked once the water evaporated (4 hours); a thermometer was not used to check the temperature of the final product. The restaurant’s process for both cooking and storing the cooked chicken likely resulted in the survival and proliferation of Salmonella. The person who typically prepares the chicken salad was not there on 7/14 and therefore could have resulted in a breakdown of their typical processes.
The restaurant voluntarily closed on 7/24 for staff to undergo a training by a hired food safety consultant and have new food safety systems put into place. The restaurant then reopened on 7/26.
Foodhandler testing for Salmonella (culture only) was conducted for 27 foodhandlers, which resulted in 1 foodhandler testing positive for Salmonella. This foodhandler was also a match to the national cluster.
On 8/5, Epi and Lab were notified by CDC that cases linked to this local restaurant cluster were linked to a national Salmonella Enteritidis 2407MLJEG-3 cluster with cases from 5 other states. Ultimately, 42 MA Salmonella cases were linked to this national cluster, 37 of which reported exposure to the Brazilian restaurant. A chicken-focused questionnaire was administered for non-MA cases. FPP obtained invoices on chicken tenders from the restaurant and provided them to USDA. A traceback was not conducted based on the lack of information from other states with cases.
