Feature Articles

(I) Food Safety Day 2009

Tripartite collaboration among food trade, consumers and the Government is important in ensuring food safety. As such, the Centre for Food Safety (CFS) organises annually a series of publicity activities to promote food safety. The theme for this year is Nutrition Labelling.

The Nutrition Labelling Scheme for prepackaged food will come into effect on 1 July 2010. The CFS has implemented a three-phase Publicity and Education Campaign on Nutrition Labelling and the first phase was formally launched in March this year. The focus of the work during the first phase is to raise public awareness of nutrition labelling.

The highlight of the event was broadcast in a programme on Radio 1 of the RTHK on 12 July 2009. If you wish to listen to the archived highlight, please visit the RTHK's website at http://www.rthk.org.hk.

(II) Aluminium in Food

The results showed that high aluminium levels were found in steamed bread / bun / cake, some bakery products such as muffin, pancake / waffle, coconut tart and cake, and also jellyfish. This means that aluminium-containing food additives have been widely used in such products. On the other hand, the results showed that aluminium contents in soya-based formula samples were in low level. Therefore, infants fed on soya-based formula are unlikely to experience major toxicological effects of aluminium.

Safety of Aluminium-containing Food

The study also revealed that the average dietary exposure to aluminium for an adult weighing 60 kg was estimated to be 0.60 mg/kg body weight / week, which amounted to 60% of the new Provisional Tolerable Weekly Intake established by the Joint Food and Agriculture Organization / World Health Organization Expert Committee on Food Additives. Yet, the potential health risk of aluminium to a high consumer cannot be ruled out. Those who consume large amount of steamed bread / bun / cake, bakery products such as muffins, pancake / waffle, and jellyfish may be at particular risk.

Advice to the Public

Examples of aluminium-containing food additives

(III) Trans Fats in Food

What are Trans Fats?

Trans fats in food has lately become a matter of grave public concern. In fact, what are trans fats? Trans fats, also known as "trans fatty acids", are unsaturated fats with at least one double bond in the trans configuration. Trans fats are made when food manufacturers turn oil from liquid form into semi-solid form through hydrogenation so as to increase the shelf life and improve the texture of food.

What Foods Contain Trans Fats?

Hydrogenated vegetable oils (such as shortening and margarines) are usually high in trans fats. Trans fats in our diet mainly come from fried food and bakery products with hydrogenated vegetable oil used as ingredients or in the cooking process. Besides, trans fats are also found naturally in the milk and the fat of sheep and cattle (such as whole milk and butter) at low level. Examples of foods that may be produced with hydrogenated vegetable oil include crackers, chips, cakes, salad dressings, pastries, dried / powdered non-dairy creamers, bread and fried products such as French fries.

What are the Health Impacts of Trans Fats in Food?

Trans fats can raise the level of low-density lipoprotein cholesterol (often called "bad" cholesterol) of our body, while at the same time lower the level of high-density lipoprotein cholesterol (often called "good" cholesterol). This increases the risk of heart disease. To eat healthily, we should select food products with low trans fats content.

Currently, the World Health Organization and Food and Agriculture Organization of Untied 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 2.2 g per day.

Study on Trans Fats Levels in Local Foods

Sampling from food premises and supermarkets, the CFS analysed the levels of trans fats in 59 food items in six groups, comprising snacks, bakery products, other ready-to-eat foods, dairy/dairy-like products, oils and fats, and beverages.

On a per 100 gram (g) basis, the highest mean trans fats content was found in oils and fats (2.3 g), followed by bakery products (0.48 g), dairy/dairy-like products (0.3 g), other ready-to-eat foods (0.13 g), snacks (0.073 g), and beverages (0.02 g).

The results showed that foods with puff pastry were high in trans fats levels. A bowl of cream soup with puff pastry had 1.6 g of trans fats, about 1.1 g of which came from the puff pastry. The total trans fats reached 73% of the recommended daily intake limit for trans fats while the amount in the puff pastry alone amounted to 50% of that limit.

In general, oils and fats as well as bakery products had high trans fats content. All vegetable oils tested contained trans fats. Besides having high trans fats content, some dairy- or cheese-containing foods also contained high saturated fats content.

Advice to Consumers

Readers' Corner

(I) Safety of Irradiated Food

What is Food Irradiation?

Application of Food Irradiation

1. Reduction of Pathogenic Microorganisms

   Ionising radiation has been shown to reduce the number of disease-causing bacteria such as Listeria monocytogenes, Escherichia coli O157:H7, Salmonella, Clostridium botulinum, Vibrio parahaemolyticus, etc. in various food commodities (seafood, fresh produce and frozen meat products). Food can also be irradiated in its final packaging.

2. Decontamination

   Spices, herbs and vegetable seasonings are valued for their distinctive flavours, colours and aromas. However, they are often contaminated by microorganisms because of the environment and the processing conditions under which they are produced. Irradiation is an effective means whereby dried food ingredients are decontaminated.

3. Extension of Shelf-life

   The shelf-life of many fruits and vegetables, meats, poultry, fish and seafood can be considerably prolonged by treatment with irradiation. Depending on the dose of ionising energy applied, irradiation produces virtually no or minor organoleptic change to the food. Exposure to a low dose of radiation has been demonstrated to slow down the ripening of bananas, mangoes and papayas, control fungal rot in strawberries and inhibit sprouting in potato tubers, onion bulbs, yams and other sprouting plant foods.

4. Disinfestation

   Irradiation has been shown to be an effective method to solve the problem of insect infestation encountered in the preservation of grains and grain products and a good alternative to methyl bromide, which is the most widely used fumigant for insect control.

Is Irradiated Food Safe for Consumption?

At high energy levels, ionising radiation can make certain constituents of food become radioactive. However, the induced radioactivity was found to be significantly lower than the natural radioactivity in food. The risk to individuals from intake of irradiated food is minimal.

Based on the experimental findings of the World Health Organization, the Food and Agriculture Organization of the United Nations, and the International Atomic Energy Agency, the Codex Alimentarius Commission has prescribed the maximum absorbed dose delivered to a food in order to forestall the induced radioactivity in the irradiated food.

Nutritional changes in food attributable to irradiation are similar to those resulting from cooking, canning, pasteurising, blanching and other forms of heat processing. Irradiation-induced changes in nutritional value depend on a number of factors: radiation dose, the type of food, the temperature and atmosphere in which irradiation is performed, packaging and storage time. In general, the quality of macronutrients (protein, lipid and carbohydrate) are not affected by irradiation and minerals have also been shown to remain stable.

Control on Irradiated Food in Hong Kong

While there is currently no irradiation facility for food treatment in Hong Kong, the labelling requirement for irradiated food is stipulated in the Food and Drugs (Composition and Labelling) Regulation of the Public Health and Municipal Services Ordinance (Cap. 132) that every container containing irradiated food shall be clearly and legibly marked with the words "IRRADIATED" or "TREATED WITH IONIZING RADIATION" in English capital lettering and "輻照食品" in Chinese characters.

Regular surveillance to monitor compliance with the labelling requirements on food irradiation is conducted by the CFS. Food commodities are collected at both import and retail levels to check if those food products that have been treated with ionising radiation are properly labelled. In 2000, 69 food samples were taken for detection of ionising treatment. Six of these samples showed positive results. As these products did not bear proper irradiation labelling, warning letters were issued to their sellers requesting the products either be withdrawn from the market or properly labelled. In all cases, the products were withdrawn. No further non-compliance was detected in subsequent surveillances conducted during the period from 2001 to 2008.

Advice to the Public

(II) Safety Tips for Consuming Hairy Crabs

Autumn is a good season for outings and savouring seasonal delicacies like hairy crabs. Mid-autumn is the best time to sample the hairy crabs. Their tender, succulent flesh and rich, delectable roes are great delicacies for crab-lovers.

Why are Hairy Crabs Called "Dazhaxie" (Big Sluice Crabs) in Chinese?

There are differences between the hairy crabs and the regular crabs. The former is characterised by a roundist-square body and thick black hairs on the legs. Their habitat is the mudholes of rivers and lakes. That is why they are also known as "hexie" (river crabs).

How does the name "dazhaxie" come about?

As hairy crabs love to chase light, a sluice ("dazha") made of bamboo and grass was used by the natives of Jiangsu to catch them. As night fell, the sluice was illuminated on one side to allure the crabs in lakes into the trap.

Advice to the Public

To ensure food safety, the public should observe the simple and effective "5 Keys to Food Safety" in the purchase, storage, preparation and cooking of hairy crabs.

Choose

• Purchase hairy crabs from reliable and hygienic shops or restaurants.
• Do not purchase dead hairy crabs as bacteria will multiply in hairy crabs for their high nutrition content once they are dead.
• Only choose live hairy crabs with intact, shiny shells without a foul smell.

Clean

• Before cooking, clean the shell, legs and claws of the crabs thoroughly with a brush and water and remove all the mud from the shell, taking care to clean the hairs of claws where dirt is usually found.
• Wash hands with warm soapy water before eating.
• Remove the internal organs of hairy crabs before eating.

Separate

• For live hairy crabs that are not intended for immediate consumption, they should be put into clean covered containers and stored in a refrigerator.
• In order to avoid cross-contamination, remember to keep raw and cooked food separately with cooked food on upper shelves and raw food such as hairy crabs on lower shelves.

Cook

• Restrict the quantity of crabs for steaming each time, and never make crabs overlap one another so that every part of the crab is thoroughly cooked.
• Do not be misled by the myth that condiments such as salt, vinegar, wine or wasabi can kill the bacteria and parasites in the crabs. Only through thorough cooking can the hairy crabs be consumed safely.

Safe temperature

• Cooked hairy crabs should be consumed as soon as possible. Never keep them at room temperature for more than two hours.

Apart from observing food safety practices, we should maintain a balanced diet and avoid overindulging in hairy crabs, especially cholesterol-rich roes. People with chronic diseases must consume hairy crabs in moderation.

(III) Cadmium in Food

What is "Cadmium" and what Contributes to "Cadmium" Exposure?

What are the Health Concerns of Cadmium in Food?

Intake of cadmium from the diet rarely causes acute toxicity, and existing evidence does not indicate cancer-causing potential through oral intake. The main concern of cadmium from dietary exposure is its chronic toxicity, particularly in the kidney. Adverse effects such as abnormal excretion of protein, glucose and amino acid in urine have been observed in patients.

How is Cadmium in Food Monitored in Hong Kong?

Advice to the Public

1. To obtain food supplies from reliable sources.
2. To maintain a balanced diet and consume foods that may have high cadmium contents (e.g. shellfish, kidney and liver) only in moderation.
3. Soak and wash vegetables, particularly leafy vegetables, thoroughly in water before cooking.
4. Do not smoke.

Food News

Turn and Look for Healthier Food Choices
Nutrition Labelling Series – Reference Amount of Food

Each of the above three ways for expressing the reference amount of food has its pros and cons. A better understanding of their differences will provide us with flexibility in using the information on nutrition labels.

1. Expressed in "per 100 g/mL"

   Advantage - Consumers can directly compare the nutrient contents of different food products if they are expressed in "per 100 g/mL".
   Disadvantage - It is difficult for consumers to estimate the quantity of food in 100 g/mL with naked eyes (e.g. how many biscuits are there in 100 g?) and therefore it is hard to know the energy and nutrient intake.

2. Expressed in "per serving"

   "Serving size" of a product usually refers to the amount of food consumed customarily at an eating occasion (for instance, an adult normally takes 4 biscuits each time and a child normally drinks half a cup of juice each time).
   Advantage - Using "per serving" as the reference amount of food enables consumers to estimate their energy and nutrient intake by referring to the number of servings they consumed.
   Disadvantage - There is no prescribed serving sizes of different food under the Nutrition Labelling Scheme to be implemented. Serving sizes of different food products can vary (e.g. one serving of Cracker A consists of 3 pieces (total weight of 45 g) while one serving of Cracker B consists of 4 pieces (total weight of 40 g)). Therefore, consumers may not be able to directly compare the nutrition information of different food products if presented in "per serving" basis.

3. Expressed in "per package"

   Advantage - Same as "per serving", using "per package" as the reference amount of food enables consumers to estimate their energy and nutrient intake by referring to the amount of food consumed (for instance, if you consume a whole package of biscuits, you will acquire the nutrients as stated on the nutrition label; if you consume half a package of biscuits, you will acquire half the amount of the nutrients listed.)
   Disadvantage – As there is also no standard for the quantity of "per package". Therefore, consumers may not be able to directly compare the nutrition information of different food products.

In conclusion, when we use nutrition labels either for comparison of the nutrient contents of different food products or for calculation of energy and nutrient intake, we should pay attention to the reference amount of food (i.e. "per 100 g/mL", "per serving" or "per package") used on nutrition labels in order to know the true meaning of these figures.

Food Safety Plan Corner

Critical Control Point of Preparing Stir-fried Chicken Fillet with Celery (for the public)

Celery is rich in potassium, which helps to regulate blood pressure. Together with chicken, it makes a delicious and healthy dish – Stir-fried Chicken Fillet with Celery. When preparing this dish for your family, you may refer to our safety tips to ensure food safety so that your family can enjoy the food safely.

Ingredients

Seasoning

Steps:

1. Rinse the celery, cut into sections.
2. Rinse the defrosted chicken fillet and cut it into thick strips. Add light soy sauce and Shaoxing wine, marinate for 15 minutes.
3. Add oil into wok. Put the celery in the wok, stir fry until cooked for later use.
4. Preheat the wok and add half a tablespoon of oil. Add ginger slices, stir fry until they smell good. Then add the chicken fillet. Add the celery when the chicken fillet strips are cooked. Stir fry evenly and serve.

Production Process

Safety Tips on Production of Stir-fried Chicken Fillet with Celery

1. Purchase
   • Purchase the ingredients from reliable and hygienic shops.
   • When buying the ingredients, make sure that:
   • the ingredients are fresh and wholesome.
   • the celery is neither damaged nor bruised on the surface.
   • the frozen chicken fillet is stored at -18℃ or below in a freezer.
   • prepackaged food items (e.g. Shaoxing wine, light soy sauce) are used before the expiry date.
2. Storage
   • Store the ingredients immediately at safe temperature as soon as possible.
     • The frozen chicken fillet should be stored at -18℃ or below in a freezer. The temperature inside the freezer should be checked regularly with a thermometer to ensure that it remains at -18℃ or below.
   • The frozen chicken fillet should be stored in a container with a lid, and put under cooked food or ready-to-eat food to avoid cross-contamination.
   • Practise the first-in-first-out principle for storage.
3. Defrost
   • Defrost the frozen chicken fillet properly by
     • storing it at 4℃ or below in a refrigerator;
     • putting it under cool running water; or
     • using a microwave oven.
4. Preparation
   • Before cooking, wash all food contact surfaces (including worktops, chopping boards and utensils) thoroughly.
   • Before cooking / in the course of preparing food, wash hands thoroughly with warm soapy water.
   • Use two different sets of utensils (including knives, chopping boards, bowls and chopsticks) to handle raw food and cooked food separately.
   • Before cooking, rinse the celery and the chicken fillet. Then, soak the celery for 1 hour or blanch it for 1 minute to reduce pesticide residues.
   • The marinated chicken fillet not for cooking immediately should be stored at 4℃ or below in a refrigerator.
5. Cooking
   • The food should be thoroughly cooked before consumption until the meat juice of the chicken fillet becomes clear and not red.
   • Use a clean food thermometer to measure the core temperature of the food, which should reach at least 75℃. (CCP)
6. Consumption
   • The cooked food should be consumed as soon as possible. It should not be kept at room temperature for more than 2 hours.

Briefing of Activities

(I) Food Safety Charter 2009

In 2008, the CFS launched the "Food Safety Charter 2008" with the aim of joining hands with the trade to promote the "5 Keys to Food Safety". The "5 Keys to Food Safety", namely, Choose, Clean, Separate, Cook and Safe Temperature, are the five simple and effective keys advocated by the World Health Organization to prevent foodborne diseases.

(II) Food Hygiene Seminar 2009

The CFS of the Food and Environmental Hygiene Department holds the Food Hygiene Seminar 2009 during the period from July to December with "5 Keys to Food Safety" as the theme. This series of seminars aims to promote proper food handling to employees of food business, staff of care centres, teachers and the wider community. Through tripartite collaboration among the Government, the public and the food trade, together with their active participation, food safety can be ensured. A topic included in the seminars is the Nutrition Labelling Scheme whose aim is to assist the public in making informed food choices by using the nutrition label , thereby promoting healthy eating.

The food hygiene seminars, 22 numbers in total, have been holding at different venues across the territory. Two of the seminars are open to the public for enrolment and participation. One was held in August and the other will be held in the Ngau Chi Wan Civic Centre on 7 December. For details of that seminar and enrolment method, please visit the website of the CFS (www.cfs.gov.hk).

The seminars, free of charge, are conducted in Cantonese. All participants will be awarded a certificate of attendance and a souvenir.

Q & A

1. In the supermarket, the shelf-life of different brands of soya milk may vary greatly. Does that mean that the longer lasting ones have a higher dose of preservatives and that we should avoid them?

The difference in shelf-life among different brands of soya milk may be due to the use of different types of heat treatment process in their production. For example, the shelf-life of products that have undergone ultra-heat treatment which virtually eliminates all microbial population can extend to months. But there may not be significant difference in terms of nutrition and other quality attributes between such products and products treated with other heat processes.

UHT, an acronym for Ultra Heat Treated, may be found on the package of products which have been treated with ultrahigh temperature. The use of preservatives in UHT products is generally considered not necessary. Also, UHT products normally do not need refrigeration until opened.

2. Why should I read nutrition labels?

Nutrition labels help you make informed food choices. You can use nutrition labels to compare food products and choose food according to your own dietary needs. For example, people with diabetes can look at the carbohydrate and sugars contents of the food products to find out whether such products are suitable for them as advised by their doctor or dietitian.

3. My mother bought a pack of low salt breakfast cereal from the supermarket the other day. Is it true that the cereal is low in sodium?

Yes. Salt is also known as sodium chloride (NaCl). Sodium is naturally present in some foods including milk. It may be used as food additives such as sodium nitrate or sodium nitrite. Under the nutrition labelling regulation, any food that makes a claim of "low salt" after 1 July 2010 must contain not more than 120 mg of sodium per 100 g of food.

Legislation

Sweeteners in Food Regulations

Under the laws of Hong Kong, sweetener means any chemical compound which is sweet to the taste, other than sugars or other carbohydrates or polyhydric alcohols. There are two categories of sweeteners, namely naturally occurring sweetening agents and synthetic compounds. They are either extracted naturally from plants or chemically synthesized. Some sweeteners are tens of times more sweet than cane sugar and only a small quantity of them will be sufficed to sweeten food, but the calories they entail are much lower than that of cane sugar. Like all the other food additives, sweeteners have to undergo stringent safety assessments before they are permitted for use in food.

According to the Sweeteners in Food Regulations made under the Public Health and Municipal Services Ordinance (Cap. 132), only the following eight groups of sweeteners are permitted for use in Hong Kong:

1. Acesulfame Potassium
2. Alitame
3. Aspartame
4. Aspartame-acesulfame Salt
5. Cyclamic Acid (and Sodium, Potassium, Calcium Salts)
6. Saccharin (and Sodium, Potassium, Calcium Salts)
7. Sucralose
8. Thaumatin