Beetroot salad contaminated with Staphylococcus aureus was the likely source of illness onboard two flights from Nepal.

The Centre for Health Protection (CHP) of the Department of Health in Hong Kong said 43 passengers, 22 men and 21 women, on two flights from Kathmandu in this month were affected.

They developed symptoms of food poisoning such as vomiting, nausea, abdominal pain, and diarrhea, about 10 to 60 minutes after having inflight meals. Patients were aged between 11 and 75 and none of them required hospitalization.

Stool samples from two patients tested positive for Staphylococcus aureus. Clinical symptoms and incubation periods were compatible with food poisoning by Staphylococcus aureus.

Role of manual preparation
CHP contacted 120 passengers on the affected flights through face-to-face interviews, phone calls, e-mails, and a hotline, as part of the epidemiological investigation.

This revealed that all 43 affected passengers had consumed food served on the plane and had not eaten any other common item before boarding. Based on results from a case-control study, the beetroot salad was the only item statistically associated with developing disease.

From 500 servings of food supplied on the two flights, the CHP collected samples, including two of beetroot salad, from the same batches of food that were left undistributed on the planes, but results showed Staphylococcus aureus did not exceed the relevant standard.

CHP found the beetroot salad had been supplied exclusively to f...