Foodborne Outbreak investigation: Hail city, Saudi Arabia,
2021. A case control study
- Water or foodborne
Background
Hail’s food safety program reported an unexpected number of food poisoning cases. All patients gave a history of sharing a meal from a fast food restaurant in Hail City on July 28–30,2021. We conducted this investigation to identify the cases, the source of the outbreak and the causative agent, if possible, and recommend preventive measures.
Methods
A case-control study was used. Cases were defined as previously well individuals who suddenly developed gastrointestinal symptoms after eating a meal from a specific fast food restaurant from July 28–30, 2021, while controls were people who ate food from the same restaurant without showing symptoms, which were selected from cases' family members. Data including demographics, symptoms, and food items consumption were collected by phone call interviews using a semi-structured questionnaire. Moreover, hospital records and laboratory data (for cases, food handlers, and food items) were reviewed.
Results
Thirty-three cases were identified, among which 52% were males, and the median age was 26.18 years (range: 3-63 years). The main reported symptoms were diarrhea (100%), abdominal cramps (84.4%), fever (94.4%), and vomiting (57.5%), while the reported incubation period was 9–38 hours. Among 5 food items consumed, garlic sauce was significantly associated with illness (odd ratio = 112.4, 95% CI = 19.1-660.5, p value <0.0001). Among the cases, 10 had their stool samples tested and 60% were positive for salmonella. There were no hospitalizations or deaths among the cases. The results of laboratory testing on garlic food items show a mixed infection (E. coli, staphylococcus and Enterobacteriaceae). Normal flora growth in food handlers' stools.
Conclusion
Based on our results, this outbreak was most probably caused by Salmonella contamination of garlic sauce. Food should be stored at the proper temperature for a safe period of time.
Hail’s food safety program reported an unexpected number of food poisoning cases. All patients gave a history of sharing a meal from a fast food restaurant in Hail City on July 28–30,2021. We conducted this investigation to identify the cases, the source of the outbreak and the causative agent, if possible, and recommend preventive measures.
Methods
A case-control study was used. Cases were defined as previously well individuals who suddenly developed gastrointestinal symptoms after eating a meal from a specific fast food restaurant from July 28–30, 2021, while controls were people who ate food from the same restaurant without showing symptoms, which were selected from cases' family members. Data including demographics, symptoms, and food items consumption were collected by phone call interviews using a semi-structured questionnaire. Moreover, hospital records and laboratory data (for cases, food handlers, and food items) were reviewed.
Results
Thirty-three cases were identified, among which 52% were males, and the median age was 26.18 years (range: 3-63 years). The main reported symptoms were diarrhea (100%), abdominal cramps (84.4%), fever (94.4%), and vomiting (57.5%), while the reported incubation period was 9–38 hours. Among 5 food items consumed, garlic sauce was significantly associated with illness (odd ratio = 112.4, 95% CI = 19.1-660.5, p value <0.0001). Among the cases, 10 had their stool samples tested and 60% were positive for salmonella. There were no hospitalizations or deaths among the cases. The results of laboratory testing on garlic food items show a mixed infection (E. coli, staphylococcus and Enterobacteriaceae). Normal flora growth in food handlers' stools.
Conclusion
Based on our results, this outbreak was most probably caused by Salmonella contamination of garlic sauce. Food should be stored at the proper temperature for a safe period of time.