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1st Issue 2007

(I) Studies on Safety of Fresh Fruits and Pre-cut Fruits

To eat more fresh fruits is healthy and to wash them thoroughly is easy.

Fresh fruits and vegetables contain nutrients, vitamins, minerals and dietary fibre, which are essential for human growth and health. In recent years, the people of Hong Kong are becoming more and more health-conscious. There is a large variety of fruits on the market and pre-cut fruits are available in supermarkets, and served in Western and Chinese restaurants as well.
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You may be concerned about whether pesticide residues (commonly called pesticides) and heavy metals are present in fresh fruits. Long-term intake of excessive pesticides and heavy metals certainly damages health. Consumption of pre-cut fruits contaminated with pathogens (such as Salmonella and Staphylococcus aureus) may cause food poisoning. In this connection, the Centre for Food Safety (CFS) has recently conducted two studies on fresh fruits to assess the potential hazard associated with pesticide residues, heavy metals as well as their microbiological quality, and the risk posed to public health.

In the study, CFS collected over 300 fresh fruit samples from retail outlets for testings on some 50 pesticides and 7 heavy metals and some 100 pre-cut fruit samples for testings on microbiological quality (including Escherichia coli, Salmonella and Staphylococcus aureus).

Test results of all fresh fruit samples and pre-cut fruit samples for pesticide residues, heavy metals and microbiological quality were satisfactory.

Nevertheless, foodborne illness outbreaks linked to fresh fruits and vegetables had occurred in other places over the past few years. The public should take note of the following when handling pre-cut fruits to prevent contamination and/or bacterial growth:

  1. The skin or rind of fresh fruits is a natural barrier for microorganism which, if damaged, may lead to microbial invasion and growth in the flesh underneath.
  2. The skin or rind of fresh fruits may be contaminated with pathogens. If fruits are not washed before cutting and peeling, pathogens on the skin or rind may be transmitted to the flesh through the knife. This may even lead to food poisoning.
  3. Unhygienic handling and processing of fresh fruits especially during cutting, slicing or peeling will increase the chances for the invasion or growth of pathogenic microorganisms and also the risk of transmission of foodborne illness.
  4. If pre-cut fruits are left at room temperature for too long or improperly stored, microorganisms are likely to multiply quickly in the flesh. Some of the microorganisms may even produce toxins.

To ensure fresh fruits (especially pre-cut fruits) are safe to eat, the public should note the following:

(1) Purchase

  1. Purchase pre-cut fruits from reliable shops holding permits or licences with endorsement for the sale of pre-cut fruits.
  2. Note the shelf life and storage temperature (at 4°C or below) of pre-cut fruits.
  3. Buy fresh fruits that are not bruised or damaged.


(2) Storage and handling of food

  1. Maintain good personal hygiene practices. Wash hands with liquid soap for at least 20 seconds before handling food or after using toilets.
  2. Use separate cutting boards and knives that are properly cleaned for ready-to-eat foods to handle fruits.
  3. Keep fresh fruits separate from non-ready-to-eat foods (such as raw meat) in the refrigerator to prevent cross-contamination.
  4. The skin or rind of fruits may be contaminated with pathogens. Therefore, before processing fruits or consumption, wash the fruits (including those with skins or rinds that will not be eaten, such as longans) thoroughly under running water. Scrub firm-skin fruits (such as melons) with a clean brush if necessary.
  5. Refrigerate cut fruits at 4°C or below until served.
  6. When transporting pre-cut fruits (e.g. to a picnic), use ice packs or put them in cooler for temperature control.

(3) Leftover

1. Discard cut fruits kept at ambient temperature for more than two hours.

In conclusion, according to the findings of the recent studies on fresh fruits and pre-cut fruits conducted by CFS, all samples are safe for human consumption. CFS advises the public to maintain a balanced diet and eat more fruits every day.

* For updated advice, please visit the webpage on Food Safety Tips for Fruits and Fruit Products

(II) Observe Food Safety Rules And Be Vigilant Against Food Poisoning

According to the Centre for Health Protection (CHP) of the Department of Health, there was an increase in the number of bacterial food poisoning cases during the period from 2003 to 2006. Since raw food may carry pathogenic bacteria, consumption of raw food or food items not thoroughly cooked poses a higher risk of food poisoning. Foods stored at temperatures favourable to the growth of bacteria or production of toxin over a long time is also prone to cause food poisoning. Common bacterial food poisoning cases in Hong Kong are mostly caused by bacteria such as Vibrio parahaemolyticus, Salmonella and Staphylococcus aureus.

Bacterial food poisoning cases
from 2003 to 2006

Source: Centre for Health Protection

Bacteria Files

Vibrio parahaemolyticus

  • Vibrio parahaemolyticus is a bacterium naturally found in the marine environment and seafood. Marine products are easily contaminated by Vibrio parahaemolyticus. Symptoms of food poisoning caused by Vibrio parahaemolyticus include diarrhea, abdominal pain, nausea, vomiting, fever etc.


  • Salmonella is usually found in the intestinal tract of human and animals. Food items easily contaminated by Salmonella include meat, poultry, milk, eggs and egg products. Symptoms of food poisoning caused by Salmonella include abdominal pain, diarrhea, nausea, vomiting, fever etc.

Staphylococcus aureus

This bacteria is frequently present in human skin, hair, nasal cavity, throat and wounds. Foods (e.g. lunch boxes, cakes, pastries, sandwiches) which have been subject to various handling procedures, with no subsequent cooking or reheating before consumption, are easily contaminated by Staphylococcus aureus. Symptoms of food poisoning caused by Staphylococcus aureus include nausea, vomiting, abdominal pain, diarrhea etc.

The best way to prevent bacterial food poisoning is to observe proper food hygiene practices at each preparation stage. In particular, we should take note of the following points:

Purchase of Food

  • Purchase food from reliable sources.
  • Do not patronise unlicensed food establishments or cooked food hawkers.
  • Do not buy ready-to-eat food that is not properly covered (e.g. siu mei and lo mei [barbecued or preserved meat] hanging outside the shops or cooked food that has not been properly covered).
  • Pay attention to the “Use By” or “Best Before” date shown on the label of pre-packaged food. When storing food, read carefully and follow the instructions on the label.
  • Do not buy food that looks abnormal (e.g. swollen or dented canned food).
Food Handling
  • Raw food, especially meat and seafood, must be washed and cooked thoroughly.
  • Wash hands with liquid soap for at least 20 seconds before handling food, or after going to the toilet or touching dirty things, e.g. clearing the refuse.
  • Anyone infected with communicable diseases such as gastroenteritis or influenza must not handle food to avoid spreading of pathogens.
  • Cuts or wounds, if any, should be covered with waterproof plaster before handling food.

Food Storage

  • Cooked food and raw food should be prepared and stored separately to avoid cross-contamination.
  • Cooked food and raw food should be stored at different racks in the refrigerator. To avoid cross-contamination, raw food should be put below cooked food.
  • Cooked food not for immediate consumption should be stored at or below 4℃ or at or above 60℃. Do not store food at room temperature to minimise bacterial growth.
  • Leftover should be discarded or kept in the refrigerator (at or below 4℃) and re-heated thoroughly before consumption.

(III) Nutrients in food – Fat and health

Many people in Hong Kong usually link fatty foods with obesity. We may have questions like “What are the nutritional value and function of fat? How does fat affect our health?”.

Fat, also known as triglycerides and composed of glycerol and fatty acids, is a class of lipids. Fat can be divided into saturated fat and unsaturated fat, depending on their chemical structures. Unsaturated fat can be further divided into mono- and poly-unsaturated fats. Edible fats and oils, butter, margarine, salad dressings, fried foods and high fat animal products are of high fat content.

High-fat foods are generally regarded as high-calorie (also known as “energy”) foods, as the calorie provided by fat is higher than that provided by carbohydrate and protein (1 gram of fat provides 9 kcal while 1 gram of carbohydrate or protein provides 4 kcal). Besides providing energy, fat carries fat-soluble vitamins (i.e. vitamins A, D, E and K) and protects organs against shock. Hence, fat is essential in our diet.
However, excessive intake of fat has been linked to major health problems, such as increased risks of cardiovascular diseases, obesity and certain types of cancers. The Food and Agriculture Organization of the United Nations has recommended not more than 30% of daily energy intake should come from fat source. Based on the daily energy intake of 2 000 kcal, the intake of fat should not be more than 65 gram.
To know more about the fat and nutrient contents of food you are about to purchase, read the information on the nutrition label when you do your shopping.

Reader's Corner

How to prevent breeding of flies in bottled soy sauce?

The various kinds of soy sauce available in the market are made by fermentation. They taste delicious, and are used in cooking, marinating or for dipping and can enhance the colour, aroma and flavour of foods.

In 2006, the Centre for Food Safety (CFS) received some 20 complaints about the presence of larvae inside bottled soy sauce. Investigation found that they were mainly the larvae of flies, and there were adult flies in some complaint articles.

The smell of fermented food (including soy sauce) is especially attractive to flies. If the soy sauce is not properly covered, flies may find their way into the container and lay eggs (some species may lay larvae) in the soy sauce.

With advanced plant facilities, modernised production technique, scrupulous production process and full attention paid to personal and environmental hygiene, the presence of larvae in the manufacture of soy sauce can be effectively prevented to meet the customer need and to comply with the requirements of the legislation. In 2006, no complaint about larvae found in unopened bottled soy sauce was received by the Centre for Food Safety.

To prevent the breeding of flies in bottled soy sauce, CFS has written to soy sauce manufacturers and importers, advising them to improve the lid design of soy sauce bottles so as to make them more user-friendly, and to remind consumers, by means of product labels, to close the lid tightly and clean the bottle thoroughly after use and to store the product properly.

Advice to Members of the Public

  • Store soy sauce properly after the seal is opened.
  • Close the lid tightly after use.
  • Clean empty soy sauce bottle thoroughly.

Food Safety Plan Corner

Safety Guidelines on Take-away Lunch Boxes

Schools, companies and organisations order lunch boxes from food factories for their students, staff or activity participants. To ensure that the bulk orders meet the food safety and hygiene requirements, the management of schools and other institutions is advised to adopt the following guidelines so as to prevent large-scale food poisoning incidents.

Points to note in selecting food suppliers

  • Select suppliers licensed by the Food and Environmental Hygiene Department (FEHD) as “Food Factory (Supplying Meal Boxes)”.
  • Before signing or renewing a contract for a long-term order of lunch boxes, or upon report of food poisoning case or food complaint involving the selected food factory, arrange a site visit to the food factory during the peak hours of its operation and pay attention to its hygienic conditions and the personal hygiene of staff to ensure observance of hygiene practices in the premises.


Points to note in the consumption of lunch boxes

  • Lunch boxes to be served hot should be kept in insulated containers (at 60 ° C or above) until consumption. Time for storage of lunch boxes should be shortened as far as practicable.
  • Further procedures such as reheating or adding gravy should not be done at the place of consumption.
  • Lunch boxes should be sampled to check food temperature prior to distribution, to ensure that hot food is kept at 60 ° C or above and chilled food at 4 ° C or below.
  • Places of consumption must be kept clean.
  • Wash hands thoroughly before eating.
  • When abnormalities are detected in lunch boxes, stop consumption immediately and lodge a complaint to the supplier and FEHD.
  • Places of consumption must be cleaned up and trash properly disposed of as soon as possible after each meal to prevent pest infestation.


(I) International Symposium on Food Safety

With “Food Safety in the New Era” as its theme, the Interna tional Symposium on Food Safety cum Official Opening Ceremony of the Centre for Food Safety, organised by the Centre for Food Safety (CFS), was held on 12 and 13 January 2007 at the Kowloon Shangri-la Hotel. Guests and speakers from local, the Mainland and overseas food authorities/ institutions shared their experience, expertise and insight on risk assessment, risk management and risk communication with respect to food safety during the two event days. The participants benefited greatly from the discussions. Here are some pictures taken by young reporter at the Symposium.

(II) Public Consultation Forums on Amendments to the Preservatives in Food Regulations

To introduce to the public on the proposed amendments to the Preservatives in Food Regulations and to seek their views on the subject, CFS held two public consultation forums on January 23 and February 7 at the Hong Kong Science Museum and the Hong Kong Central Library respectively. At the forums, views were freely expressed and the proposed amendments actively discussed. Before the proposed amendments are finalised, CFS will thoroughly consider the views expressed by the public at the forums and through other means.


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