Are Hong Kong’s pre-packed salads safe to eat? Health officials warn of general risks
Overall standards in city’s shops are ‘acceptable’, but one of 101 samples tested found to be contaminated
Pregnant women, children, the elderly and people with weak immune systems should avoid consuming pre-packaged salads because of the risk of infection from a common bacteria found in the food item, Hong Kong authorities said on Friday.
Tony Chow Chor-yiu, Centre for Food Safety acting principal medical officer, said a form of bacteria found in salads – listeria – could lead to complications such as septicaemia, meningitis or even death if ingested by people who were vulnerable.
However, he assured the public that the overall hygiene quality of salad products in the city was “acceptable” as all but one of the 101 samples tested fulfilled safety standards.
The survey, conducted from September last year to February, involved products drawn from restaurants, wet markets, supermarkets and convenience stores across the city.
Among the 101 samples, eight contained vegetables from hydroponic farming – plants grown from mineral nutrient solutions instead of soil – and four were from aquaponic sources – plants farmed under a form of aquaculture.
All samples went through microbiological tests for E coli O157, salmonella and listeria, conducted by the public health laboratory services branch of the Health Department.
The only problematic sample was found in mid-November last year, from vegetables used in a smoked salmon salad dish in a Sha Tin restaurant. As much as 2,400 Listeria per gram was detected – 24 times the safe amount stipulated by the centre’s Microbiological Guidelines For Food.
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Three possible causes of contamination in this case were suggested by the centre. The restaurant might have used contaminated raw materials, failed to maintain adequate temperature control, or contaminated the food in the post-processing stage.
“Listeria can survive and grow in rather cold environment, such as at 4 degree Celsius, so refrigerated food with a long shelf life is even more at risk,” Fong Long-yan, research officer heading the survey, said.
Chow said the severity of illnesses caused by the consumption of the contaminated salad varied according to a person’s health conditions.
Food safety authorities advised the public to prepare their own salads instead of buying ready-to-eat packs off shelves. These items should also be consumed or disposed of as soon as possible.
Those who cook at home were also reminded to keep their hands clean and observe proper hygiene by using separate cutting boards for raw food.
The centre said the restaurant was ordered to stop selling the food item in question. The eatery also voluntarily suspended its operations for thorough cleaning and disinfection.
Subsequent inspections and follow-up examination of food samples from the restaurant were also conducted. Results were satisfactory, according to the centre.
Officials did not reveal the name of the restaurant.
