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Food Safety Bulletin for Consumers 2012 (4 th Issue)

Published by the Centre for Food Safety

Feature Article

Regional Symposium: Food Claims - Truth and Myth

Mrs Marion LAI (in the middle), the Permanent Secretary for Food and Health (Food) and Mr Clement LEUNG, the Director of Food and Environmental Hygiene take a group photo with other government officials and the guest speakers

Picture above: Mrs Marion LAI (in the middle), the Permanent Secretary for Food and Health (Food) and Mr Clement LEUNG, the Director of Food and Environmental Hygiene take a group photo with other government officials and the guest speakers.

Claims made about the nature, contents and functions of food in relation to their nutrition and health effects have been widely used in various forms in the food world.  Some people consider them useful for highlighting to the potential consumers the contents and functions of the food, while others are skeptical about any possible exaggeration or even misleading comments made for the mere purpose of boosting sales.  A balance between protection of consumer health and promotion of fair practice in international food trade seems to be crucial.

In this connection, the Centre for Food Safety (CFS) organised the Regional Symposium "Food Claims: Truth and Myth" in the Hotel Nikko Hongkong at Tsim Sha Tsui East, Kowloon on 29 and 30 October 2012.  The Symposium gathered experts on food science, academics, food traders including the research and development personnel, consumers, and those from food regulatory authorities to examine the current development of nutrition and health claims, explore the market and scientific research directions, and exchange views on various regulatory approaches.

The Symposium consisted of three main topics:

  1. Nutrition and Health Claims – what, how, and who
  2. Regulation, Compliance, and Impact
  3. Scientific Substantiation and Communication

The Symposium drew food safety experts from overseas, the Mainland and the local community to deliver keynote speeches to share their experience and expertise.  Guest speakers included Dr. Basil MATHIOUDAKIS from Directorate-General for Health and Consumers, European Commission; Dr. Albert FLYNN from Scientific Panel on Dietetic Products, Nutrition and Allergies, European Food Safety Authority; Dr. Barbara O SCHNEEMAN from Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration; Mr Dean STOCKWELL from Food Standards Branch, Food Standards Australia New Zealand; Dr. E-Siong TEE from TES NutriHealth Strategic Consultancy, Malaysia; Dr. Nobuyoshi SHIOZAWA from Food Labelling Division, Consumers Affairs Agency, Japan; Professor Yuexin YANG from National Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention; Ms Connie LAU, Chief Executive, Consumer Council of Hong Kong; and Dr. Philip HO, Consultant (Community Medicine) (Risk Assessment and Communication), Centre for Food Safety.

Participants attentively listen to the speakers and actively take part in the discussion sessions to exchange views

Pictures: Participants attentively listen to the speakers and actively take part in the discussion sessions to exchange views.

Participants listen intently to the speaker

Picture above: Participants listen intently to the speaker.

Speakers engage in interactive discussions with the participantsThe Symposium was a huge success, attracting over 400 participants, including representatives from Government departments and the Mainland and overseas authorities, members of the food trade, medical practitioners, nutritionists, academics and students.  The Symposium was well received with positive feedback.  Most of the participants found the Symposium useful in building bridges and forging closer links between the parties concerned, which were important for the protection of public health.

Speakers engage in interactive discussions with the participantsMoreover, the CFS orgainsed the Workshop "Scientific Evaluation of Nutrition and Health Claims" in the Hong Kong Academy of Medicine Jockey Club Building on 31 October 2012.  The Workshop aimed to discuss the principles and issues surrounding scientific substantiation of nutrition and health claims from consumer, trade and regulatory perspectives, and to discuss the application of theories and practices related to evidence-based practice on scientific evaluation of nutrition and health claims.

Picture on the right: Speakers engage in interactive discussions with the participants.

Seasonal Food (Hotpot) Safety Tips:

When having hotpot, we should bear in mind the Five Keys to Food Safety, especially the one about separating raw and cooked food.  We should not put too many dishes on the table to avoid cross-contamination between raw and cooked foods.  Separate sets of chopsticks and utensils with different appearances should be used to handle raw and cooked foods.  In addition, foods should be thoroughly cooked.

Readers' Corner

Dangerous Drugs in Food Flavourings
Regulation of Gamma-Butyrolactone

The amendments to the Dangerous Drugs Ordinance (Cap. 134) (the "Ordinance") were gazetted in May 2012, specifically listing gamma-butyrolactone (GBL) as a dangerous drug.  The amendments to the Ordinance took effect on 14 July 2012.

GBL is a chemical which can be used as a food flavouring agent and as a solvent for removing rust or superglue. It may also be used for producing other chemical products.  As it is a substance possessing psychoactive characteristics, GBL is liable to abuse.

According to relevant literature, GBL can be quickly converted into gamma-hydroxybutyric acid (GHB) (commonly known as "Rape Water"), a dangerous drug already specified in the First Schedule to the Ordinance, inside the human body.  The Department of Health advised that GBL does not have any known pharmaceutical use, and that the consumption of GBL could cause adverse effects similar or even identical to those of GHB, such as vomiting, hypotonia, tremors, seizures, aggression, impairment of judgment, coma, respiratory depression, hypothermia and bradycardia.

It is known that certain flavourings may contain GBL.  However, even if the flavourings used in foods or drinks contain GBL, the amount of GBL in the foods or drinks produced is so small that will not pose any food safety problem.

In view of this, under the amendments to the Ordinance, GBL has been specifically listed as a dangerous drug.  Besides, an exemption provision has been included to allow the use of GBL at a level reasonably safe for human consumption.  The relevant clause provides for exemption in respect of a preparation of GBL containing not more than 0.1% of GBL, being a preparation compounded with one or more other ingredients in such a way that the preparation has no, or a negligible, risk of abuse and that the GBL cannot be recovered by readily applicable means or in a yield which would constitute a risk to health.

For more information on the provisions under the Ordinance, please visit the Bilingual Laws Information System (BLIS) at

Answers: (1) No  (2) No  (3) Yes  (4) Yes

Listeria monocytogenes and High-risk Individuals

According to the Centre for Health Protection, the number of Listeria monocytogenes infections reported annually in Hong Kong between 2004 and 2011 ranged from 3 to 17.  Nonetheless, there were already 21 reported infections in January to August 2012, hitting a record high since the disease was listed as a statutory notifiable infectious disease in 2008.  High-risk individuals should pay special attention to food hygiene so as to prevent being infected with Listeria monocytogenes.

Listeria monocytogenes is a pathogenic bacterium.  It is universally found in the environment, particularly in soil, vegetation, animal feed, and in human and animal faeces.  Such bacterium can survive and multiply at temperature as low as 0°C, but can be easily destroyed under normal cooking temperature.

Consuming Listeria contaminated food may lead to the development of a disease called listeriosis.  Although infections in healthy people are mostly asymptomatic, foodborne listeriosis is a relatively rare but serious disease with high fatality rates (20% - 30%) to the groups at risk, i.e. pregnant women, newborns, the elderly and immunocompromised individuals such as patients with AIDS, diabetes mellitus, cancer or kidney disease. Symptoms usually appear within 3 to 70 days (estimated median incubation period is three weeks) after consuming contaminated food, which include flu-like illness, nausea, vomiting, abdominal cramps, diarrhoea, headache, constipation and persistent fever.  Serious infections of Listeria monocytogenes are manifested by septicaemia and meningitis.

Prevention of Listeria infections is of major concern in pregnant women.  Even though symptoms may be relatively mild in mothers, the passage of Listeria monocytogenes through the placenta may cause miscarriage, stillbirth or perinatal septicaemia and meningitis in the newborns.

To minimise the risk of Listeria infections, high-risk individuals should avoid high-risk foods like long shelf life refrigerated ready-to-eat foods, such as soft cheese, pate, processed cold meats (e.g. smoked salmon, ham, smoked chicken), or uncooked vegetables or desserts like salad, tiramisu, etc.

Advice to Consumers:

  • Maintain good food and personal hygiene.
  • Check whether the food packaging is intact and the expiry date on the label is not overdue, especially long shelf life refrigerated ready-to-eat foods.
  • Consume perishable foods that are precooked and ready-to-eat as soon as possible.
  • Reheat leftovers thoroughly before consumption.

Additional Advice to the Groups at Risk:

  • Avoid high-risk foods, such as ready-to-eat items with shelf lives longer than 5 days under refrigeration, unless cooked thoroughly.

Origin of Genetically Modified Food

Long ago, humans learned to apply the techniques of cross breeding in order to produce plants and animals with desirable characteristics (e.g. high yield and better adaptation to the growth environment).  With the development of science and technology, the conventional approach of cross breeding, which is more time-consuming, is no longer the only way of modifying foods.  We are now turning to biotechnology in selecting and modifying genes, by which species with the desired characteristics can be obtained in a faster manner.

A gene is a unit of hereditary material which is made up of deoxyribonucleic acid (DNA).  It carries the required information necessary for protein(s) synthesis in a cell, which determines the characteristics of an organism.  By modifying genes in plants or animals, we can change the characteristics of the organisms.  With modern biotechnology, we are now able to transfer genes between different species and specifically modify the genetic make-up of different organisms in a faster and more precise manner, so as to obtain species with certain characteristics.  Genetically modified (GM) organisms can be applied directly for food use (e.g. GM tomato) or to produce products used as food additives or processing aids (e.g. aspartame, an artificial sweetener used in soft drinks, which is produced by GM bacteria).

The research and development of GM food is not only targeted at the reduction of production cost, increased yield, enhanced pest resistance for crops and minimised pesticide usage in crop cultivation, but also production of crops with enhanced nutritional content and improved flavour and texture.  It can even help to remove certain potential allergens from crops.

While the use of genetic engineering may provide us with food of better quality, the potential risks associated with GM foods/crops have always been the cause of concerns of green groups and consumer groups over the followings:

  1. the unintended modification of similar conventional species in the neighbouring fields due to cross pollination with GM crops;
  2. the potential disturbance to the ecological balance by GM crops;
  3. the emergence of super pests due to growing GM crops;
  4. whether it is acceptable to move genes between plants or animals which do not normally interbreed; and
  5. the unknowing intake of foods containing genes from something which would never be eaten for religious, health (e.g. food allergy) or other reasons.

For the sake of putting the potential risks of GM food under control, national authorities of GM food producing countries have put in place safety assessment schemes.  Such a move helps to ensure that newly developed GM organisms, before available on the market, have passed the safety assessment and hence would not pose health threats to human and are suitable for human consumption.

Food Safety Q&A

Q:       What is the difference between trans fats and saturated fats?

The process of hydrogenation turns vegetable oils from liquid to semi-solid formA:        Fats can mainly be categorised into saturated fats and unsaturated fats.  Saturated fats are solid in form at room temperature.  They are abundant in animal fats such as butter and lard, as well as some vegetable oils (e.g. coconut oil and palm oil).  Unsaturated fats are generally found in vegetable oils (e.g. corn oil and peanut oil) and they are liquid in form at room temperature.  However, having undergone "hydrogenation" (i.e. addition of hydrogen), unsaturated fats turn from the form of liquid into semi-solid, and trans fats are produced in the process.  Food manufacturers often use hydrogenated vegetable oils as ingredients to extend the shelf life of food products and improve their texture. 

Both saturated fats and trans fats raise the level of "bad" cholesterol in our body and increase the risk of coronary heart disease, while trans fats lower the level of "good" cholesterol at the same time and thus increase the risk of coronary heart disease to a greater extent.

Picture on the right: The process of hydrogenation turns vegetable oils from liquid to semi-solid form.

Fried food and bakery products in which hydrogenated vegetable oils are used as ingredients or in the cooking process are the main sources of trans fats in our diet.  A low level of trans fats is found naturally in the milk and the fat of sheep and cattle (e.g. full cream milk and butter).  The World Health Organization and the Food and Agriculture Organization of the United Nations suggest that diets should provide a very low intake of trans fats.  In practice, this implies an intake of less than 1% of daily energy intake.  For example, an individual with a daily energy intake of 2 000 kcal should limit the intake of trans fats to less than 2.2g per day.

Advice to Public:

  • Maintain a balanced diet, eat less deep-fried and fatty foods.
  • Read food labels and choose foods with lower trans fats content, avoid foods produced with hydrogenated vegetable oil or fats, such as margarine, shortening, crackers, chips, cookies, French fries, cakes, salad dressing and dried/powdered non-dairy creamers.
  • Choose foods low in saturated fats and trans fats, since both will increase the risk of cardiovascular diseases.

Picture below: Eating less deep-fried and high fat food is recommended.

Eating less deep-fried and high fat food is recommended

News on New Dishes

So Tender and Appetising: "Fried Fish with Sweet and Sour Sauce"

Fried Fish with Sweet and Sour Sauce, succulent fish fillets with a crispy coatingA sweet and sour sauce made with green peppers, tomatoes, pineapples, etc. goes perfectly well with fried fish.  The "Fried Fish with Sweet and Sour Sauce" is a delicious dish featuring succulent fish fillets with a crispy coating and an appetising sauce.  In this issue, it is our honour to have invited Mr HO Po-lung, head chef of Super Star Seafood Restaurant, to demonstrate how to prepare the dish.  Super Star Seafood Restaurant is a signatory of the Food Safety Charter.

Picture on the right: Fried Fish with Sweet and Sour Sauce, succulent fish fillets with a crispy coating.

  Preparation Steps Small Tips, Big Wisdom
First, purchase sole fillets and other ingredients from approved and reliable suppliers.  Upon receipt of the ingredients, check with meticulous care to ensure their freshness.  After receiving, vegetables should be stored in a refrigerator at 4°C while frozen sole fillets in a freezer at -18°C for later use. 
Defrost the frozen sole fillets under running tap water.  Wash the vegetables. Frozen food can be defrosted within a short period of time by putting it under running tap water.  This method of defrosting frozen food will prevent bacterial growth by avoiding prolonged storage of food at room temperature or food temperature danger zone.  Apart from putting the food under running tap water, food can also be defrosted in the chilled compartment of a refrigerator or in a microwave oven. 
Cut the sole fillets (320 g) into rib-shaped slices.  Other ingredients: green pepper (1/4 pc), red pepper (1/4 pc), tomato (1 pc), pineapple (1 slice) and a suitable amount of spring onion, all diced.. Cutting sole fillets into rib-shaped slices shortens the cooking time and makes it easier to cook the fillets thoroughly. 
Season the sole fillets with  salt, sugar and chicken powder (each half a teaspoon) and then dip the fillets in a suitable amount of beaten egg and cornflour.  Eggs should be stored in a refrigerator at 4°C before use. 
frying Shallow frying
Shallow fry the sole fillets in preheated oil for about 3 to 4 minutes.  Place the shallow-fried fillets on paper towel to absorb oil and then on a dish for later use. Shallow-fried fillets should not be left at room temperature for more than 2 hours should be avoided .
Add a small amount of water to the wok.  When water boils, add the cut ingredients, a suitable amount of ketchup, sweet and sour sauce and cornflour to thicken the sauce.  After bringing the thickened sauce to the boil, pour it onto the sole fillets.  Ready to serve. The sauce should be kept boiling for at least 1 minute before being poured onto the sole fillets.  The food should be consumed immediately. 

Tips from Chef HO:

  1. One can make use of the sweet and sour sauce available in the market and dilute the sauce with water to adjust its concentration according to personal taste.  If ketchup is not available, cooking with only the sweet and sour sauce will do as well.  Sweet and sour sauce should be added to the wok at the last step because with vinegar as its ingredient, the longer it cooks, the darker it will become, which in turn will spoil the appearance of the dish.  Moreover, use of broth or chicken broth in the sauce is not required as it will overwhelm the fresh flavour of tomatoes.
  2. Utensils of different colours or types should be made available in the kitchen for identification for different uses.  For example, yellow plastic gloves can be used for handling raw meat; black plastic gloves for cleansing purposes; and disposable gloves for handling ready-to-eat food for the purpose of hygiene and convenience.
  3. Super Star Seafood Restaurant strictly observes the principle of separating raw and cooked foods, including storing raw and cooked foods in separate refrigerators and handling raw and cooked foods with cutting boards, knives and utensils of different colours to avoid cross-contamination.
  4. Instructions on the use and storage of various utensils, with full illustrations and descriptions, are posted at conspicuous places as constant reminders and easy reference for staff.
  5. A supervisory system is put in place to ensure food and environment cleanliness (hygiene).  Various codes of hygiene and operational guidelines are laid down for staff . Furthermore,  on-the-job hygiene training is provided.
  6. Each refrigerator is managed by a designated staff member.  Information such as the names of the responsible staff and the maintenance contractor and their contact numbers are posted on the door of each refrigerator to facilitate monitoring of refrigerator temperature and regular maintenance.

Food Safety Plan Corner

Fried Fish with Sweet and Sour Sauce - Frozen Sole Fillets Must be Defrosted Thoroughly


Frozen sole fillets, red peppers, green peppers, tomatoes, pineapple slices, chopped spring onions and eggs

Salt, sugar, chicken powder, sweet and sour sauce and cornflour


  1. Defrost the frozen sole fillets and cut them into rib-shaped slices.  Season with salt, sugar and chicken powder.
  2. Brush the sole fillets with beaten egg and coat with cornflour.  Shallow fry until done and put aside for later use.
  3. Dice red peppers, green peppers, tomatoes, pineapple slices and spring onions.  Cook until done.  Add sweet and sour sauce and cornflour for thickening, and pour sauce onto sole fillets.

Production Process

Production Process

 Critical Control Point

Truth against Fallacy

"Fresh Wrap" for Vegetables

Q:    Is wrapping fresh vegetables directly with newspaper before storing them in refrigerator the best way to keep them fresh?

A:    Many people wrap fresh vegetables with newspaper before storing them in refrigerator, believing that vegetables can thus be preserved longer.  As we all know, printing ink comes off easily from newspapers and it often stains our hands after reading newspapers.  Printing ink for newspapers is complicated in composition.  Apart from pigments, various industrial organic solvents may be used in its manufacturing process.  It may also contain heavy metals such as lead and cadmium. Printing ink may transfer to the surface of the vegetables if they are wrapped with newspaper and may not be easily detected by naked eyes.  Prolonged exposure to these chemicals may pose potential risks to human health.  As such, wrapping vegetables with newspaper is not a wise way to keep them "fresh".

Advice to Public:

  1. Do not wrap vegetables with newspaper.
  2. Avoid buying vegetables wrapped with newspaper.
  3. Do not wet the vegetables after purchase.  Keep them dry before putting them in plastic bags.
  4. Store vegetables in perforated plastic bags, or wrap them with white cloth or paper towel before putting them in plastic bags.
  5. Soak vegetables in water for some time and rinse thoroughly before cooking.

Tips for Getting the Temperature Right

Store Foods at Safe Temperature

All cooked foods should be consumed as soon as possible.  For those not for immediate consumption, they should be kept at above 60oC before serving.  When reheating foods, make sure that the core temperature reaches at least 75oC.  To prevent bacterial growth, leftovers should be stored in refrigerator within 2 hours to keep them at 4oC or below.  Leftovers should not be stored in refrigerator for more than 3 days and should not be reheated more than once.  Discard foods that perish, stink or go mouldy due to possible prolonged or improper storage.

Briefing of Activities

Roving Exhibitions on Food Safety in 2013

The CFS holds a series of exhibitions in shopping centres of public and private housing estates across the territory every year.  Panels covering topics such as food safety and nutrition are displayed and audio-visual programmes are shown to enhance public knowledge on food safety and making suitable food choices.  New arrangements of the exhibitions will be announced regularly and members of the public are welcome to visit the CFS website.

For any enquiries, please contact our Communication Resource Unit on 2381 6096.

Upcoming Activities

Public Talks 2013

To enhance the awareness and knowledge of the public on food hygiene and safety, the CFS plans to assign experienced health inspectors of its Communication Resource Unit to deliver food hygiene talks in 2013.  The talks, with the target audience being the general public in various districts, will be conducted in Cantonese and the duration of each talk will be about 2 hours.  Leaflets and souvenirs promoting "Food Safety" messages will be given out during the talks.  New arrangements of the talks will be announced regularly and members of the public are welcome to visit the CFS website.

For any enquiries, please contact our Communication Resource Unit on 2381 6096.

Brain Gym

  1. Is it all right to wrap vegetables with newspaper?
  2. Is it true that trans fat causes no harm to human health?
  3. Is it true that saturated fat increases the "bad" cholesterol and trans fat decreases the "good" cholesterol in the human body?
  4. Was the Regional Symposium on Food Claims: Truth and Myth held between 29 and 30 October 2012?

(Answers can be found on page 4.)

Enquiry and Subscription

Printed copies of the Food Safety Bulletin can be collected at the Communication Resource Unit located at 8/F, Fa Yuen Street Municipal Services Building, 123A Fa Yuen Street, Mong Kok, Kowloon. For enquiry, please call 2381 6096.  The public may also visit the website of the Centre for Food Safety ( for the online version.