Hong Kong’s  Center for Food Safety (CFS), a unit of  the Food and Environmental Hygiene Department announced on Monday the results of a recently completed targeted food surveillance project on Bacillus cereus and Clostridium perfringens in ready-to-eat foods.

Except for a preserved bean curd sample detected with excessive Bacillus cereus, which was announced earlier, test results of the remaining samples were all satisfactory.

“A total of 300 samples of ready-to-eat food were collected from different retail outlets, including online retailers, and food factories for testing of Bacillus cereus and Clostridium perfringens this year. The samples included dim sum, rice, noodles, pastries, soya products, stewed meat and meat sauce,” according to a CFS spokesman.

Bacillus cereus is commonly found in the environment. It can form spores which are able to resist heat and survive cooking temperature. Bacillus cereus can produce different toxins causing two types of food poisoning. One, “emetic intoxication” is caused by heat-stable toxins in food and causes vomiting, the other type of poisoning causes diarrhea and usually follows ingestion of a large amount of Bacillus cereus that produces toxins in the intestine. As the production of preserved bean curd requires fermentation, Bacillus cereus will multiply when production is not hygienic or storage is not proper.

Food poisoning caused by Clostridium perfringens is usually associated with inadequately cooked foods or cooked foods that are cooled for a prolonged period or stored under sub-optimal temperature. Foods prepared in bulk, especially cooked meat and poultry dishes, and those stored at room temperature with long cooling periods after cooking, are at high risk. In food poisoning caused by Clostridium perfringens, common symptoms include vomiting, diarrhea and abdominal pain, and sometimes fever. Prolonged and severe symptoms are more likely to appear in the young, the elderly and those with a weaker immune system.

The CFS spokesman reminded food businesses and the public not to take the risk lightly. The agency of the Hong Kong Special Administrative Region of the People’s Republic of China said good personal and food hygiene is required to ensure food safety. It offered the following tips:

  •  When handling food that is not to be consumed immediately, keep it at a safe temperature.
  • Consume perishable prepackaged food and beverages promptly after opening or reheating and avoid prolonged storage at ambient temperatures.
  • Reheat food thoroughly with the core temperature at 75 degrees C or above.
  • If cooked foods are to be cooled, the trade should adopt measures to shorten the required cooling time to restrict the growth of Bacillus cereus and Clostridium perfringens in heat treated food. For example, install specific rapid chilling equipment, divide food into smaller portions and place it in shallow containers and in an ice bath.
  •  Monitor the refrigerator temperature and maintain a temperature log.
  • Cross-contamination of food during cooling and storage should be prevented.

CFS also said food manufacturers  should also observe the Good Hygienic Practices in each stage of production to ensure safe and proper processing of the food and to comply with the limits stipulated in the Microbiological Guidelines for Food.

Hong Kong is an autonomous territory on the Pearl River Delta of China.

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