Sushi fans have to choose food premises carefully as sushi may easily be contaminated by bacteria during the production process.
For it would seem that they are comparatively more at risk of bacterial food poisoning.
The Consumer Council and the Centre for Food Safety (CFS), have conducted a joint test on a wide array of food samples of everyday rice and noodles.
A total of 114 samples were drawn randomly from different outlets across the territory - restaurants (Chinese, Western and Japanese), cafes and supermarkets - and put through the test to assess their microbiological quality.
By and large, the results were reassuring with the great majority (96%) of the food samples classified as either "satisfactory" (Class A) or "acceptable" (Class B), under the Microbiological Guidelines for Ready-to-Eat Food issued by CFS.
Only 4 samples - 3 of them sushi - were deemed "unsatisfactory" (Class C) in terms of their food hygiene or safety quality.
This means that close to 20% of the sushi test samples, 3 out of 16, fared unsatisfactorily in the test.
Two of the sushi samples were found with a total Aerobic Colony Count (ACC) of 1,600,000 cfu/g and 2,000,000 cfu/g, exceeding the "acceptable" (Class B) limit of below 1,000,000 cfu/g (for Food Category 3).
The other sushi sample was identified to contain 510 cfu/g of the foodborne pathogen Staphylococcus aureus (S.aureus), which indicated a sub-optimal microbiological safety level but still within the range of 100 cfu/g - 10,000 cfu/g for "unsatisfactory" level (Class C).
The consumption of food contaminated by bacterial pathogens exceeding the safety levels may cause food poisoning. Affected persons usually show gastrointestinal symptoms of nausea, abdominal pain, diarrhea and vomiting; fever may also develop. The incubation period varies from hours to days depending on the type of bacteria.
The fourth sample, a cold noodle dish, was detected with an ACC of 380,000 cfu/g, in excess of the "acceptable" (Class B) limit of below 100,000 cfu/g (for Food Category 2), as well as Escherichia coli (E.coli) of 400 cfu/g.
All 4 samples in question were sourced from restaurants at different locations between the months of July and September this year.
It is of no coincidence that these 4 samples were served cold for consumption. In the case of sushi, some may include raw ingredients. Personal hygiene and cleanliness in handling, and proper storage are therefore crucially important in the preparation of these foods.
The CFS has given health advice to the licensees of the restaurants concerned, and has taken follow-up samples and noted the improvements.
Consumers are advised to:
- patronize hygienic and reliable licensed food premises;
- consume ready-to-eat rice and noodles as soon as possible;
- store cooked rice and noodles not consumed immediately at above 60?℃ (hot storage) or at 4℃ or below (cold storage); and
- reheat refrigerated rice and noodles thoroughly, if applicable to core temperature of at least 75℃.
Between January and September this year, a total of 359 cases of bacterial food poisoning outbreak were reported. These cases concerned all types of food.
There were 500 such cases in 2007, 838 cases in 2006, and 740 cases in 2005.
For more details, consumers are advised to refer to the test report in this December issue of CHOICE.
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