To commemorate a patriotic poet, Qu Yuan, of the Chu Kingdom who lived around 300 B.C., it is a Chinese tradition to eat glutinous rice dumplings during the Dragon Boat Festival on the 5th day of the fifth month of the Lunar Calendar. The main ingredient of dumpling is glutinous rice, and stuffing to enhance flavour of the dumpling include green bean, pork, salted egg, chestnut, mushroom, bean paste, etc. Glutinous rice dumplings are wrapped by lotus or bamboo leaves.

In the old days, people used to make glutinous rice dumplings themselves to celebrate the Festival. However, the busy city life drives many people to purchase ready-made ones from restaurants, food shops or supermarkets.

Some unscrupulous merchants have been reported to add boric acid into glutinous rice dumplings to prolong their shelf life. The sale of glutinous rice dumplings containing non-permitted preservatives such as boric acid contravenes the Preservatives in Food Regulations (Cap.132BD). Upon conviction, an offender shall be liable to maximum penalty of a fine up to $50,000 and imprisonment for 6 months.

Under the Food Surveillance Programme, health inspectors of the Centre for Food Safety take samples of glutinous rice dumpling from market for chemical and microbiological testing before the Festival to ensure that glutinous rice dumplings sold in Hong Kong are safe for human consumption. The chemical testing is conducted for preservatives (such as boric acid, salicylic acid and benzoic acid), heavy metals (such as arsenic, cadmium and mercury), pesticide residues (such as methamidophos and DDT) and colouring matters (such as Sudan dyes), while the microbiological testing for pathogenic bacteria (such as Salmonella, Staphylococcus aureus and Bacillus cereus).

The public should pay attention to the following safety tips on the purchase, preparation and consumption of glutinous rice dumplings:

Buying rice dumplings

• Buy rice dumplings from reliable outlets;
• When purchasing non-prepackaged rice dumplings, choose those that are securely wrapped in wrapping leaves; and
• When purchasing prepackaged rice dumplings, check the expiry date and whether the packaging is intact.

Home-made rice dumplings

• Buy wrapping leaves from reliable suppliers and avoid leaves that are unnaturally bright green or with chemical smells;
• Wash hands and utensils thoroughly before and after handling food; and
• Handle raw and cooked food separately to avoid cross-contamination.

Storing and preparing rice dumplings

• Consume rice dumplings as soon as possible and avoid prolonged storage;
• Both the glutinous rice and stuffing should be well covered until the rice dumplings are unwrapped. Do not come into direct contact with the strings upon cooking to prevent contamination at all times.
• Store rice dumplings at 4 degrees Celsius or below, or store them properly according to the instructions on the package if they are not consumed or cooked immediately;
• Keep cooked rice dumplings that are not consumed immediately in a covered container and put them in the upper compartment of the refrigerator. Keep raw food in the lower compartment to prevent cross-contamination;
• Reheat rice dumplings thoroughly until the core temperature reaches 75 degrees Celsius or above before consumption;
• Do not reheat rice dumplings more than once; and
• Consume reheated rice dumplings as soon as possible.

Consuming rice dumplings

• Wash hands with running water and liquid soap, and rub for at least 20 seconds before consumption; and
• Reduce seasonings such as soy sauce or granulated sugar during consumption.