Sunday, 2 March 2008

Bird flu and food

International agencies such as the WHO and the Food and Agriculture Organisation (FAO) state that it is safe to eat fully cooked poultry and eggs, as high temperatures in cooking destroy the avian influenza virus. - Reuters photo

The Stars on line
Sunday March 2, 2008

Avian influenza and food safety.

AVIAN influenza, or “bird flu”, is an infectious disease of animals caused by type A strains of the influenza virus. The virus normally infects only birds and, less commonly, pigs. It sparked worldwide concern when the deadly H5N1 strain of virus crossed the species barrier and claimed human victims in isolated, but nonetheless headline grabbing cases.

Although infected wild migratory water fowl are thought to be primarily responsible for spreading the virus from location to location, experts recognise there are many other potential routes to a global pandemic, such as international travellers, or outbreaks not recognised and contained quickly enough.

Short history

Outbreaks of the highly pathogenic avian influenza H5N1 strain of virus was found among poultry flocks in eight Asian countries (Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand, and Vietnam) during the period of late 2003 and early 2004.

At that time, it is estimated that more than 100 million birds in the affected regions either died from the disease or were killed in order to try to contain the outbreaks. By March 2004, the outbreak was reported to be under control.

Since late June 2004, however, new outbreaks of H5N1 influenza among poultry have been reported in several countries in Asia and Eastern Europe (Cambodia, China, Indonesia, Kazakhstan, Malaysia, Mongolia, Russia, Siberia, Tibet, Thailand, Turkey, Romania, Ukraine and Vietnam). It is believed that these outbreaks are ongoing.

Additionally, outbreaks of influenza H5N1 have been reported among wild migratory birds in China, Croatia, Mongolia, and Romania.

Human cases of influenza A (H5N1) infection have been reported in Cambodia, China, Indonesia, Thailand, Vietnam and most recently, Turkey.

Its impact on human health

Avian influenza does not usually infect humans, but human outbreaks and some deaths have been reported in a small number of countries in Asia, and additionally now in Europe.

According to the World Health Organization (WHO), approximately 150 human cases have been reported since 2003, with just over 50% of them proving fatal. To date, all human infections have been linked to people working in or living near poultry, such as farms and animal markets.

Experts believe that human infections can occur because the H5 strain under some circumstances is able to jump the species barrier. As of now, only a few human cases of bird flu have been reported and this suggests that the virus is not easily transmitted from birds to humans.

Nevertheless, international health authorities are spearheading preventive measures to contain the spread of infection and minimise the possibility of the virus strains mutating to a form which could be both highly infectious to humans and highly pathogenic (illness-causing). This could happen, for example, if a person was infected with both human and avian influenza viruses at the same time.


Control measures recommended to contain the spread of the virus include:

- Raising awareness amongst those handling or rearing poultry and encouraging early detection and notification.
- Rapid destruction (“culling” or “stamping out”) of all infected or exposed birds, proper disposal of carcasses, and the quarantining and rigorous disinfection of farms.
- Seasonal influenza vaccines for poultry workers.
- Restrictions on movement of live poultry, both within and between countries.
- International financial support to fund control measures required.
- Creation of country-specific guidelines and regional coordination programmes.

What about eating poultry and eggs?

International agencies such as the WHO and the Food and Agriculture Organisation (FAO) state that it is safe to eat fully cooked poultry and eggs, as high temperatures in cooking destroy the avian influenza virus.

Similarly highly processed chicken and egg products are also safe to consume, according to manufacturers recommendations, because the high temperatures used in processing will destroy the virus and other micro-organisms.

New research confirms that industrial pasteurisation processes of egg products is sufficient to inactivate the heat sensitive Avian influenza virus. The research shows that using temperatures and times of heat application similar to those used in commercial pasteurisation of liquid egg products are sufficient in deactivating the H5N1 strain of virus.

Here are some simple food safety tips to help ensure that the poultry and eggs that reach the table are both free of the avian flu virus and other micro-organisms such as salmonella and campylobacter which can cause other illnesses.

When buying poultry or eggs: Purchase only poultry and poultry products from shops with evident high food hygiene standards or look for those retailers or caterers with national authority certification of good hygiene practices.

Avoid buying live poultry, as bird flu can spread through close contact with infected live poultry.

Select fresh poultry meat and other products that have no signs of damage or infection, such as unusually dark colour, hemorrhage etc.

Select fresh eggs, without faeces staining on the shell. Avoid buying eggs with cracked shells.
Canned poultry products and chicken essence can be safely consumed, as all processed foods undergo a heat treatment process that effectively destroys viruses.

When storing / thawing poultry and eggs: Freeze or clean and cook poultry as soon as you reach home from a shopping trip, as existing viruses multiply rapidly in raw meat at room temperature.

Keep poultry on the bottom shelf of the freezer to prevent drippings from falling on and contaminating other food. To prevent cross-contamination, avoid storing uncooked poultry beside cooked meat.

Store eggs in the refrigerator.

Avoid thawing frozen poultry at room temperature, as this encourages existing viruses to multiply.
Thaw poultry in the refrigerator the night before and place a pan below to catch the drip. If thawing in a microwave, finish cooking in a conventional oven immediately. Poultry can be thawed as part of the cooking process as long as it reaches a safe internal temperature (see below for more details).

When handling uncooked or frozen raw poultry: Avoid touching the nose, eyes, and mouth when handling food and wash hands thoroughly (about 20 to 30 seconds) with soap and hot water before and after contact with any food product, to keep your hands virus-free. Use separate chopping boards for cooked and raw products.

Separate raw meat from cooked and other raw foods to avoid cross-contamination.

If you cut your hand whilst cleaning poultry, wash the wound with an antiseptic, cover the wound with a waterproof plaster and wear clean gloves whilst cleaning poultry.

Scrub and sanitise the draining board, sink, utensils and chopping boards with hot soapy water, as they may become contaminated when poultry is washed, cleaned and cut. Discard worn out boards, as cut marks on them serve as hiding places for viruses.

Wash sponges and towels frequently with 10% bleach solution, as they can serve as a source of cross contamination.

When handling an egg: Wash the outside of eggs and wash hands after handling an egg, as the egg shell may be contaminated with bird faeces.

When cooking poultry and eggs: WHO recommends that poultry should be cooked to reach an internal temperature of 70ºC for 30 minutes or 80ºC for 1 minute. To check that poultry is well-cooked – juices should run clear and meat near the bone should not be pink. A cooking thermometer can also be used to check cooking temperature.

When cooking in the microwave, cover poultry, stir, and rotate either on a turntable or manually for even cooking, as microwave heat can leave cold pockets inside the poultry where harmful micro-organisms such as bacteria and viruses can survive.

Never partially cook poultry for final cooking later. Bacteria and viruses can survive and grow in partially cooked meat. Cook eggs until the yolks and whites are firm.

Avoid recipes that require the use of raw or partially cooked eggs (for example, mayonnaise or mousse, soft-boiled eggs or a sunny-side-up). Use pasteurised processed egg products instead.
Don’t handle food more than needed – use forks and tongs. Never dip fingers in food to taste.
When eating: Wash your hands before eating. Heat poultry thoroughly before eating, as micro-organisms grow best in warm temperatures.

If fully cooked poultry is purchased, it should be picked up hot and brought home for immediate consumption.

Do not allow any cooked poultry to sit out at room temperature for more than two hours. Refrigerate leftover poultry as soon as it cools slightly and eat it within three or four days.
Never taste leftover poultry that looks or smells strange. When in doubt, throw it out. Reheat leftover poultry until steaming hot.

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