Influenza A(H1N1): Let Them Eat Pork!

May 7, 2009

Earlier today, the World Health Organization (WHO, together with the Food and Agriculture Organization (FAO, a UN body) and the World Organization for Animal Health (OIE) reissued the following joint statement in an attempt to clarify their stance on the safety of eating pork during the current influenza outbreak.

"In the ongoing spread of influenza A(H1N1), concerns about the possibility of this virus being found in pigs and the safety of pork and pork products have been raised.

Influenza viruses are not known to be transmissible to people through eating processed pork or other food products derived from pigs.

Heat treatments commonly used in cooking meat (e.g. 70°C/160°F core temperature) will readily inactivate any viruses potentially present in raw meat products.

Pork and pork products, handled in accordance with good hygienic practices recommended by the WHO , Codex Alimentarius Commission and the OIE, will not be a source of infection. 

Authorities and consumers should ensure that meat from sick pigs or pigs found dead are not processed or used for human consumption under any circumstances."

eFoodAlert has been reviewing research reports on the subject, in an effort to clarify this food safety issue for our readers. Here is what we've found.

Influenza Virus Is Restricted To The Respiratory System In Swine

USDA researchers deliberately infected pigs (through the nose) with both swine influenza viruses and with highly pathogenic avian influenza viruses. They collected organ samples from the infected pigs to determine how far the viruses spread through the body. In all cases, the influenza viruses were limited to the respiratory system – the lungs, trachea, nasal passages and tonsils. None of the other organs showed any evidence of influenza virus infection.

The researchers also investigated whether pigs could develop influenza when fed meat from chickens that were infected with avian influenza. Although the animals developed an antibody reaction to the virus, none of the pigs developed symptoms of influenza. The virus was recovered from nose and tonsil samples, but not from rectal swabs. It is likely that the pigs developed mild infections as a result of contact between the infected meat and their tonsils.

Influenza Virus Is Inactivated By Heating

Influenza viruses are inactivated within 5-6 minutes at 51ºC (125ºF), and in no more than a second or two at 70º-74ºC (158º-165ºF). USDA already recommends that poultry meat be cooked to an internal temperature of 160ºF to ensure that bacterial pathogens have been killed. 

Influenza Virus Survives For Longer Periods On Non-porous Surfaces Than On Porous Surfaces

Influenza virus particles can remain active at room temperature for hours – even days – on some inert, non-porous surfaces. These include plastic,  stainless steel (the particles are inactivated much more quickly on copper), and even Swiss banknotes, which are made using a non-porous resin. The virus particles die far more rapidly on porous surfaces, such as facial tissues; they also are inactivated rapidly on human skin.

What does this mean for someone who likes to eat pork?

• All of the federal and state agencies who have weighed in on this issue claim that a pig suffering from influenza would not be approved for slaughter. Even so, it's possible that an infected pig that is not yet exhibiting symptoms might get past this initial screening.
  
• While the influenza virus doesn't appear to invade organs outside of the respiratory system, it's possible that some live virus particles may be spread over other parts of the carcass during organ removal (evisceration) in the slaughterhouse.
  
• Stray influenza virus particles that happen to land on edible parts of the carcass almost certainly would become inactivated between the slaughterhouse and the supermarket.
  
• Any residual stray virus particles that manage to survive the trip from slaughterhouse to household kitchen will be killed by standard, recommended cooking procedures.
  

In a nutshell, it is safe to prepare and eat pork.