The Centre for Food Safety (CFS) of the Food and Environmental Hygiene Department today (December 30) announced the results of a risk assessment study on the microbiological quality of packaged rice balls. All samples were compliant with the microbiological food safety criteria for pathogenic bacteria (i.e. Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus). The overall result was satisfactory.
A spokesman for the CFS said, “Rice balls in convenient packages can facilitate consumers to consume them on-the-go and has thus gained in popularity. The CFS conducted a study and collected 63 pairs of samples of packaged rice balls from four takeaway chains and five supermarket chains or convenience store chains in different regions of Hong Kong between February and March this year. The change in microbiological quality after leaving the samples concerned under ambient conditions for a period of time was assessed against the criteria stipulated in Microbiological Guidelines for Food.”
The study results showed that the overall microbiological quality of the samples was satisfactory. Only one rice ball sample with braised salmon was detected to have an excessive level of E. coli, resulting in an unsatisfactory rating for hygienic quality, but there was no food safety concern. This indicated that there may be room for improvement in the food manufacturing and handling processes. The CFS has provided advice on the food preparatory process to the concerned manufacturer. A follow-up sample was taken, and the result was satisfactory.
Furthermore, regarding the change in microbiological quality of packaged rice balls after leaving the samples concerned under ambient conditions for a period of time, among the 58 samples to which the aerobic colony count (ACC) criterion was applicable, only one sample kept at ambient conditions after purchase for four hours was found to be borderline for ACC, while all the others were found to be satisfactory. However, three of these samples had an ACC more than 10 times higher than the control samples that were refrigerated at 4°C or below immediately after purchase. The ACC is an indicator of quality rather than safety and hence does not indicate a food safety concern. Nevertheless, the ACC can provide useful information about the general quality and remaining shelf life of the food.
The food trade should follow Good Hygiene Practices at all times and consider the advice below regarding the safe handling of packaged rice balls:
- Food handlers should receive proper training to prepare rice balls properly and prevent contamination of rice balls;
- The preparation areas for raw food should be separated from areas for handling ready-to-eat food as far as possible to minimise potential cross-contamination;
- The schedule or sequence of rice ball preparation should be planned to avoid leaving perishable/ready-to-eat ingredients under ambient conditions for too long;
- In general, rice balls intended to be displayed for a prolonged period should be refrigerated after preparation;
- Control measures for limiting microbial growth so that the rice balls can be kept at temperatures above 4ºC for a certain period of time should be validated; and
- Recommendations on storage conditions should be provided for the safe handling of rice balls by consumers.
Members of the public are also reminded to take heed of the following recommendations to ensure the food safety of packaged rice balls:
- Consume rice balls as soon as possible after purchase;
- For packaged rice balls, follow the storage instructions available on the packaging and consume them before the use-by date;
- Refrigerate packaged rice balls at 4°C or below if they are not to be consumed immediately.
The study is available on the CFS’s website at
www.cfs.gov.hk.
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