The Centre for Health Protection announced today that it has completed an investigation into clusters of food poisoning among passengers on flights from Nepal.

It explained that an epidemiological probe was carried out due to food poisoning clusters among passengers on two Cathay Pacific Airways flights, flight number CX640 from Kathmandu, Nepal, earlier on.

Based on the results of the investigation, the centre said it did not rule out that the food poisoning clusters were caused by beetroot salad contaminated with Staphylococcus aureus served on board the flights. 

The investigation revealed that a total of 22 men and 21 women on CX640, which arrived in Hong Kong on January 8 and 9, developed symptoms of food poisoning such as vomiting, nausea, abdominal pain and diarrhoea about 10 to 60 minutes after having inflight meals.

In addition to pointing out that none of the affected people, aged between 11 and 75, required hospitalisation, the centre stated that stool samples from two patients tested positive for Staphylococcus aureus.

The overall clinical symptoms and incubation period of the affected people were compatible with food poisoning caused by Staphylococcus aureus.

The centre successfully contacted 120 passengers on board the affected flights through face-to-face interviews, telephone calls, emails and the centre’s hotline to conduct a comprehensive epidemiological investigation.

Additionally, the investigation revealed that all 43 affected passengers had consumed food served on board the aircraft and they had not eaten any other common food before boarding.

Based on the analysis of the case-control study, the beetroot salad served on board was the only food item that was statistically significantly associated with developing disease, suggesting that the consumption of beetroot salad was a risk factor for the disease.

Out of approximately 500 servings of food supplied on the two flights, the centre collected two samples of food servings, including two samples of beetroot salad, from the same batches of food that were left undistributed on the two airplanes, and the test results showed that Staphylococcus aureus did not exceed the food safety standard.

During the probe, the centre found that the beetroot salad had been supplied exclusively to the flights operated by Cathay Pacific Airways from Kathmandu to Hong Kong since this January.

The centre’s staff inspected the food factory twice and found that the preparation of the beetroot salad involved a number of manual handling steps that might increase the risk of contamination with Staphylococcus aureus.

On January 10, the centre instructed the food factory to stop supplying the beetroot salad. Since then, there have been no further reports of food poisoning on related flights.

To reduce the risk, the centre has recommended the food factory to minimise manual handling during the food preparation process, and to use utensils and equipment to avoid direct hand contact with food ingredients as far as possible.

Furthermore, it stated that all food handlers are required to strictly adhere to hand hygiene guidelines, especially during food preparation processes that involve manual handling without subsequent heating steps.