CFS announces risk assessment study results on microbiological quality of packaged rice balls
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 foodas 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 canbe 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.
DH announces latest situation of Legionnaires' Disease cases
The Centre for Health Protection (CHP) of the Department of Health today (April 7) reported the latest number of cases of Legionnaires' disease (LD), and reminded the public of the importance of using and maintaining properly designed man-made water systems, adding that susceptible groups should strictly observe relevant precautions.
From March 30 to April 5, the CHP recorded two community-acquired LD cases. The details of the cases are as follows:
A 54-year-old male patient with underlying illnesses livingin Kwun Tong District; and
A 59-year-old female patient with underlying illnesses living in Eastern District.
The CHP is conducting epidemiological investigations to identify potential sources of infection, high-risk exposure and clusters, if any.
As of April 5, 37 LD cases had been recorded this year. In 2024 and 2023, there were 135 and 121 LD cases respectively.
Men, people aged over 50, smokers, alcoholics and persons with weakened immunity are more susceptible to LD. Some situations may also increase the risk of infection, including poor maintenance of water systems; living in areas with old water systems, cooling towers or fountains; using electric water heaters, whirlpools and spas or hot water spring spas; and recent stays in hotels or vessels.
Legionellae are found in various environmental settings and grow well in warm water (20 to 45 degrees Celsius). They can be found in aqueous environments such as water tanks, hot and cold water systems, cooling towers, whirlpools and spas, water fountains and home apparatus that support breathing. People may become infected when they breathe in contaminated droplets (aerosols) and mist generated by artificial water systems, or when handling garden soil, compost and potting mixes.
Immunocompromised persons should:
Use sterile or boiled water for drinking, tooth brushing and mouth rinsing;
Avoid using humidifiers, or other mist- or aerosol-generating devices; and
If using humidifiers, or other mist- or aerosol-generating devices, fill the water tank with only sterile or cooled freshly boiled water, and not water directly from the tap. Also, clean and maintain humidifiers/devices regularly according to manufacturers' instructions. Never leave stagnant water in a humidifier/device. Empty the water tank, wipe all surfaces dry, and change the water daily.
The public should observe the health advice below:
Observe personal hygiene;
Do not smoke and avoid alcohol consumption;
Strainers in water taps and shower heads should be inspected, cleaned, descaled and disinfected regularly or at a frequency recommended by the manufacturer;
If a fresh-water plumbing system is properly maintained, it is not necessary to install domestic water filters. Use of water filters is not encouraged as clogging occurs easily, which can promote growth of micro-organisms. In case water filters are used, the pore size should be 0.2 micrometres (µm) and the filter needs to be changed periodically according to the manufacturer's recommendations;
Drain and clean water tanks of buildings at least quarterly;
Drain or purge for at least one minute infrequently used water outlets (e.g. water taps, shower heads and hot water outlets) and stagnant points of the pipework weekly or before use;
Seek and follow doctors' professional advice regarding the use and maintenance of home respiratory devices and use only sterile water (not distilled or tap water) to clean and fill the reservoir. Clean and maintain the device regularly according to the manufacturer's instructions. After cleaning/disinfection, rinse the device with sterile water, cooled freshly boiled water or water filtered with 0.2 µm filters. Never leave stagnant water in the device. Empty the water tank, keep all surfaces dry, and change the water daily; and
When handling garden soil, compost and potting mixes:
Wear gloves and a face mask;
Water gardens and compost gently using low pressure;
Open composted potting mixes slowly and make sure the opening is directed away from the face;
Wet the soil to reduce dust when potting plants; and
Avoid working in poorly ventilated places such as enclosed greenhouses.
The public may visit the CHP'sLD page, theCode of Practice for Prevention of LDand theHousekeeping Guidelines for Cold and Hot Water Systems for Building Managementof the Prevention of LD Committee, and the CHP'srisk-based strategyfor prevention and control of LD.
