Food Safety Focus (141st Issue, April 2018) – Incident in Focus
Review of Food Poisoning Outbreaks Related to Food Premises and Food Business in 2017
Reported by Dr. Addi CHAN, Senior Medical Officer,
Risk Management Section,
Centre for Food Safety
This article reviews the food poisoning outbreaks related to local food premises and food business that were reported to the Centre for Food Safety (CFS) of the Food and Environmental Hygiene Department in 2017.
Food Poisoning Outbreaks Related to Local Food Premises and Food Business
Food poisoning is a statutory notifiable disease in Hong Kong. To protect public health, the CFS, in collaboration with the Department of Health (DH), is responsible for the investigation and control of food poisoning outbreaks (FPOs) related to local food premises and food business. In 2017, the CFS received 185 food poisoning cases referred from the DH which affected 711 persons. The annual number of referred cases showed a general decreasing trend over the past decade (see Figure 1).
Figure 1: Number of food poisoning outbreaks related to food premises and food business and the corresponding number of persons affected from 2007 to 2017.
Causative Agents and Contributing Factors
Bacterial foodborne agents remained the leading causes (65.4%) of all FPOs in 2017, with Salmonella (SM), Vibrio parahaemolyticus (VP), and Clostridium perfringens (CP) being the top three bacterial pathogens. For the viral causes, norovirus accounted for around 21.6% of all the FPOs referred to the CFS. Of the 185 cases reported, inadequate cooking, contaminated by raw food and contaminated raw food were the most frequently identified contributing factors. The importance of good hygiene and food safety practices in safeguarding food safety could be illustrated by the following two major food poisoning outbreaks that occurred in 2017.
10 Clusters of Food Poisoning Outbreaks Related to Inadequate Cooking and Improper Storage
In late October to early November 2017, 10 clusters of FPOs related to a restaurant affecting a total of 22 persons were reported to the CFS. Stool specimens of seven victims in four clusters were cultured positive for Salmonella enteritidis. Epidemiological investigation of these clusters showed that they were related to the consumption of scrambled egg in fusilli or noodle.
Our field investigation revealed that the incriminated food, scrambled eggs was prepared in semi-cooked condition in advance and kept in room temperature for prolonged period of time. Upon receiving an order from the customer, the semi-cooked scrambled egg was just placed on top of the fusilli/noodle without any further reheating or cooking.
The lapse in hygiene practice, inadequate cooking and improper storage of scrambled eggs were the contributing factors to these FPOs. Specific health advice was conveyed to the food handlers, in particular, the risk of inadequate cooking and improper storage of cooked food was emphasised. The sale of the food items were suspended immediately and the food premises were instructed to carry out thorough cleansing and disinfection. The hygiene condition of the food premises was kept under close monitoring. Follow up food sample was collected after resumption of sale of scambled eggs and the result was negative and no further FPO outbreaks were received afterwards.
Eggs are commonly consumed food. However, eggs may be contaminated with Salmonella and hence eating raw or undercooked eggs may result in salmonellosis. The above example revealed the importance of thorough cooking and proper storage of dishes with scrambled eggs. The trade is advised to choose pasteurised eggs or egg products to prepare dishes not requiring further heat treatment.
Food Poisoning Outbreaks Related to the Consumption of Raw or Under-cooked Blood Cockles Contaminated by Pathogens
In 2017, the CFS received 11 clusters of FPOs related to blood cockles affecting 44 persons in different restuarants. The suspected pathogens included norovirus, Vibrio parahaemolyticus and Salmonella. Investigation of these cases revealed that inadequate cooking of raw blood cockles or pre-packed pickled blood cockles were the contributing factors. Indeed, according to traders, these pre-packed pickled blood cockles were not ready-to-eat food and further cooking is required but clear instruction of further cooking was not provided on the package. The traders were therefore instructed to provide relevant information, such as clear instruction on packing. Health education was provided to concerned food premises to purchase food ingredients from reliable supplier, as well as the importance of adequate cooking of blood cockles. The number of FPOs related to blood cockles decreased afterwards.
Conclusion
While it appeared that the number of food poisoning outbreaks has remained at relatively low level over the past few years, the CFS will continue to be vigilant in safeguarding food safety. On the other hand, the trade and public need to recognise the risks involved and follow the “Five Keys to Food Safety” to prevent food poisoning outbreaks. The trade should also ensure the food sold is fit for human consumption.