In a joint study conducted by the Consumer Council and the Centre for Food Safety (CFS) on a wide array of "higher risk" buns and sandwiches for their microbiological quality, 4 samples were found to be unsatisfactory.
The samples, a total of 113 buns (57) and sandwiches (56), were purchased from various eatery outlets, supermarkets and bakeries across the territory.
By and large, the results were reassuring with the majority (96%) of the samples classified as either "satisfactory" (Class A) or "acceptable" (Class B), under the Microbiological Guidelines for Ready-to-eat Food (the Guidelines) issued by CFS.
There were 4 samples - 1 hot dog and 3 coconut and cream buns（椰絲奶油包）- deemed "unsatisfactory" (Class C) in terms of their food hygiene and/or safety quality, meaning that the licensees of the food premises concerned should find out the causes and adopt measures to enhance food safety assurance.
2 coconut and cream bun samples, and one hot dog sample were detected to contain high level of Staphylococcus aureus (from 150 cfu/g, to 9,600 cfu/g), which indicated a sub-optimal microbiological safety level but were still within the range of 100 cfu/g - <10,000 cfu/g for "unsatisfactory" level (Class C). When Staphylococcus aureus population reaches 10,000 cfu/g, the food can be potentially harmful to its consumers.
The consumption of food contaminated by Staphylococcus aureus exceeding the safety levels may cause food poisoning. The onset of symptoms is usually rapid (e.g. within 4 hours) and the affected persons usually show gastrointestinal symptoms of vomiting, abdominal pain and diarrhea; prostration may sometimes occur. However, among all buns and sandwich samples tested in this study, none of them has exceeded the safety level for Staphylococcus aureus.
Staphylococcus aureus are bacteria commonly present in the nasal cavity, throat, hair and skin of healthy individuals. Since the production of certain buns and sandwiches (e.g. hot dogs, coconut and cream buns) may involve manual handling processes after baking, the bacteria could be passed from the food handlers to the food if proper personal practices are not adopted.
In general, artificial cream with high sugar content does not support the growth of harmful bacteria and therefore its storage at room temperature could be safe theoretically. However, if there is improper preparation and storage practices that render the artificial cream contaminated, bacteria may grow rapidly and affect the microbiological quality of the artificial cream and final products.
On aerobic colony count (ACC), two coconut and cream bun samples were found with a total ACC of 1,000,000 cfu/g and 2,300,000 cfu/g, exceeding the "acceptable" (Class B) limit of below 1,000,000 cfu/g (for Food Category 3).
The assessment of ACC is based on Food Categories. Due to the nature or production process of the foods, Food Category 5 samples (e.g. raw vegetables, cheese) may contain naturally existed and usually harmless microorganisms leading to a possibility of higher level of ACC. However, this may not be related to a poor hygienic condition and thus, the ACC of Food Category 5 samples are not applicable to the assessment of the overall microbiological quality of the samples.
Results of the current study revealed that some of the Food Category 5 samples had a relatively high ACC and the level varied among different samples in the same food group, in extreme cases, the level of ACC could be as high as 100 million cfu/g.
According to microbiologists, the following individuals should avoid consuming raw vegetables and soft cheese: immunocompromised, patients with liver diseases or major underlying illnesses, patients on antacids or other drugs that reduce the acidity in the stomach, pregnant women, young children and elderly.
The CFS has given health advice to the licensees of the bakeries concerned. Regarding the bakeries of the coconut and cream buns concerned, CFS has taken follow-up samples from them and noted the improvements. While for the bakery of the hot dog concerned, the bakery indicated to CFS that they have stopped selling hot dogs.
Consumers are advised to:
- patronize hygienic and reliable licensed food premises;
- consume purchased buns and sandwiches as soon as possible;
- if buns and sandwiches with higher microbiological risk are not consumed immediately, store them in refrigerator (at 4℃ or below), and consume them within 1 or 2 days, or within shelf-life.
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