The number of foodborne outbreaks decreases in Hong Kong

Outbreaks concerning food premises and businesses were reported to the Centre for Food Safety (CFS) of the Food and Environmental Hygiene Department in 2018.

Food poisoning is a statutorily notifiable disease in Hong Kong. With the Department of Health, the CFS is responsible for investigating and controlling outbreaks related to local food premises and businesses.

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CFS has referred 158 foodborne outbreaks affecting 641 people from the Department of Health. The annual number of referred cases has decreased slightly in the past few years.

Bacterial foodborne agents remained the leading causes (82 per cent) of all outbreaks with Salmonella, Vibrio parahaemolyticus, and Bacillus cereus being the top three.

Viral causes accounted for around 12.7 per cent of the outbreaks and all were related to norovirus. Inadequate cooking, contamination by raw food and improper holding temperature were the most frequently identified contributing factors.

Last year the CFS identified almost 2,000 food incidents from a system designed to monitor and review incidents that occurred outside Hong Kong. About 450 of these recalled on the Food Incidents Surveillance System (FISS) related to undeclared allergens.

For incidents with local relevance, 46 per cent of cases related to microbiological hazards, 33 per cent to chemical, 15 per cent to physical and 6 per cent to others (e.g. substandard qualities).

From late February to mid-March 2018, six clusters of outbreaks related to a restaurant affecting 16 people were reported to the CFS. Stool specimens of two victims in two clusters were positive for Salmonella enteritidis. Epidemiological investigation of these clusters by the Department of Health suggested they were related to consumption of various dishes with stir-fried eggs on the same day.

An investigation found that unpasteurized eggs were used and cooked for a very short time before serving. Health advice was given to food handlers and the premises was advised to suspend the sale of food items and carry out thorough cleansing and disinfection. After irregularities such as inadequate cooking of food were rectified no further outbreaks were reported.

CFS advises trade to choose pasteurized eggs, egg products or dried egg powder to prepare dishes not requiring further heat treatment.

From late May to early June 2018, three outbreak clusters related to consuming products from a cooked food stall were reported to the CFS, with six people affected. Two victims submitted stool specimens for testing and both were positive for Vibrio parahaemolyticus.

The epidemiological assessment indicated the ready-to-eat food package with cooked cuttlefish and tofu was the possible source. Field investigation revealed products were marinated at room temperature for hours next to a working table for preparing raw seafood. Then they were packed and kept in a display showcase for sale until five to six hours later. The temperature of the display was measured at 29 degrees Celsius during the inspection.

Cross-contamination by raw food and improper holding temperature of cooked food may have contributed to the outbreak. Health advice was provided to the premises and sale of food items was suspended immediately. The site was thoroughly cleaned and disinfected. Follow up visits found no additional cases after the change of practices.