First Step in Managing a Hospital Food Poisoning Outbreak
The first step is to conduct a case-control study to identify the specific food items consumed by the ill staff members compared to those who remained well, not to close the restaurant immediately. 1
Rationale for Epidemiologic Investigation First
The evidence from documented foodborne outbreak investigations consistently demonstrates that determining what the infected individuals ate is the critical first step before implementing control measures. 1
In the Dallas County sodium azide poisoning outbreak, investigators immediately began epidemiologic investigations to identify the contaminated food vehicle through case-control methodology, which successfully identified iced tea as the source (OR = 65). 1
Epidemiologic tools are valuable for active case-finding and confirming suspected contaminated food vehicles, even in the absence of an identified pathogen. 1
The investigation should compare food exposures between the 13 ill staff members (cases) and the 37 well staff members (controls) who also ate at the restaurant. 1
Why Not Close the Restaurant First
While closure may seem intuitive, premature closure without identifying the specific contaminated item can:
Fail to prevent ongoing exposure if the contaminated food item is still being served or prepared elsewhere in the hospital. 1
Miss the opportunity to collect critical food samples and environmental specimens before they are discarded or cleaned. 1
In the Dallas outbreak, authorities conducted a site visit the same evening and only temporarily suspended the specific implicated item (iced tea), not the entire facility. 1
Immediate Parallel Actions
While conducting the epidemiologic investigation, you should simultaneously:
Interview all 13 ill staff members to document specific foods and beverages consumed, timing of consumption, and symptom onset. 1
Interview a sample of the 37 well staff members as controls to identify which exposures are associated with illness. 1
Collect stool samples from symptomatic staff for culture and toxin testing. 2, 3
Collect and refrigerate samples of all foods served during the implicated time period before they are discarded. 1
Test asymptomatic as well as symptomatic food handlers, as carriers can be the source of contamination. 2
Common Pitfalls to Avoid
Do not assume all foods are equally suspect—the investigation must identify the specific vehicle. 1
Do not delay the epidemiologic investigation while waiting for laboratory results, as the case-control study can proceed immediately and guide targeted testing. 1
For rapid-onset foodborne illnesses (symptoms within 1-4 hours), consider chemical poisons or preformed bacterial toxins, not just infectious pathogens. 1, 4
Do not overlook the possibility of intentional contamination, particularly in self-service areas accessible to multiple individuals. 5
When to Close the Restaurant
Closure should occur after the epidemiologic investigation identifies the contaminated food source, allowing for: