 Risk of PAHs in Barbecued Meats What are PAHs? PAHs (polycyclic aromatic hydrocarbons) refer to a large group of organic
chemicals containing rings of carbon and hydrogen atoms. PAHs are present
everywhere in the environment as pollutant in air, soil, water and foods.
They are formed during incomplete combustion of fuels and organic substances
and are also present in vehicle emissions and tobacco smoke. What are the sources of PAHs? Food attribute to the major exposure (about 90%) to PAHs for non-smokers.
However for smokers, significant contribution of PAH exposure may be attributed
to cigarette smoking. Since PAHs are ubiquitous in the environment, they
are present in almost all food, although they are rarely found in high
levels in raw foods. Cooking methods such as roasting and grilling, on
the other hand, will generate more PAHs and result in higher levels of
PAHs. Also, charred foods have a higher PAH level. That said, people love
barbecued foods may take in more PAHs. What are the health concerns of PAHs? PAHs will undergo metabolic transformation in the human body and may
form products that are excreted or active metabolites that may bind to
DNA, the genetic materials inside the cell. The latter pathway is considered
to be related to the cancer causing potential of PAHs. Three PAHs are
classified as "probably carcinogenic" to human (i.e. Group 2A) by the
International Agency for Research on Cancer of the World Health Organization
and are of more concern, but none of the PAHs is classified as carcinogenic
to humans (i.e. Group 1). Since cancer-causing potential is the concern and that some PAHs can
damage genetic materials inside cells, it is not possible to define a
level of intake which is without risk. The Joint FAO/WHO Expert Committee
on Food Additives is of a view that exposure to PAHs should be as low
as practicable. Local Study on PAHs The Food and Environmental Hygiene Department has conducted a study on
PAHs. Samples of barbecued meats (siu mei, namely roasted pork, BBQ pork
and roasted ducks, and dried meats, namely dried beef and dried pork)
were collected and analysed. We found that the higher the cooking temperature,
the more PAHs will be generated; the closer the distance of the food from
the heat source, the higher the PAH levels. Furthermore, PAH levels tend
to be higher on the skin and fat portion (the outer part) of roasted ducks;
and the cooking method of charcoal grilling gives rise to more PAHs in
foods when compared with gas grilling and electric oven roasting methods.
Having said that, we also observe that PAH levels in siu mei prepared
by electric oven roasting and gas grilling are comparable to those found
in other foodstuffs in other overseas studies. In other words, siu mei
prepared in these ways is not a particular high risk food item. How to reduce the risk? With reference to the findings of our above-mentioned study, to minimise
the risk of exposure, we have the following recommendations to the trade
and consumers - For the trade
- For making "Siu Mei", gas grilling or electric oven roasting is preferred
to charcoal grilling. For making dried meat, electric grilling is preferred
to gas grilling;
- Avoid direct contact of meats with flame and avoid fats from dripping
onto the heat source (this can be done by trimming off visible fats
before barbecuing and proper design of heating chamber); and
- Cook meats at the lowest possible cooking temperatures and avoid overcooking.
However, the meat should be cooked thoroughly to destroy foodborne pathogens.
- Prior to grilling and roasting, the meat could be cooked partially
by a method which employs a lower cooking temperature such as boiling.
For consumers
- Do not overindulge in barbecued meats;
- Do not eat charred foods;
- Maintain a balanced and healthy diet by eating plenty of fruits and
vegetables; and
- When going for barbecuing, trim visible fats before barbecuing; avoid
foods from flame and fats from dripping onto the heat source; and pre-cook
foods (e.g. by boiling) before barbecued.
Risk Assessment Section
November 2004 Further information |
