a grill with flames and tongs turning some charred meat.

Polycyclic Aromatic Hydrocarbons (PAHs)

General

Polycyclic aromatic hydrocarbons (PAHs) are a group of hundreds of different chemicals formed primarily during the incomplete combustion of organic materials such as coal, oil and gas, wood and garbage. PAHs are usually found as a mixture containing two or more of these compounds; cigarette smoke contains many PAHs. PAHs are present in air, water, soil and food. (Abdel-Shafy et. al., 2016). PAHs are found in common processed food groups such as dairy, processed (e.g., charcoal-broiled or smoked) seafoods and meats, fats and oils, roasted or toasted foods like cereals, grains, nuts and coffee.

During food processing and cooking (e.g. roasting, grilling, smoking, heating, baking, and drying), PAHs can form, and their levels depend on variables such as cooking temperature, duration and methods, reuse and storage (Singh et. al., 2016). Higher cooking temperature generally leads to higher production of most PAHs, due to greater evaporation of PAHs from heated oils into the air and the formation of PAHs through the pyrolysis of partially decomposed organic compounds in food and cooking oils. Foods with higher fat content release more PAHs compared to low-fat foods.

The effects of environmental exposure to low levels of PAHs on human health remain unknown. However, high concentrations of naphthalene in the air can irritate the eyes and respiratory passages. Workers exposed to significant amounts of naphthalene (a commonly detected PAH) through skin contact with its liquid form or by inhaling its vapor have experienced blood and liver abnormalities. Additionally, several PAHs and certain mixtures of PAHs are known to be carcinogens, particularly lung, skin, and bladder cancers.

Commission Regulation (EU) No. 835/2011 of 19 August 2011 listed maximum levels for PAHs in foodstuffs. Some PAHs that are on the California Proposition 65 list include:  anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[j]fluoranthene, chrysene, dibenzo[a,h]pyrene, dibenzo[a,i]pyrene, and 5-methylchrysene. Proposition 65 does not specify fixed permissible limits for each chemical; instead, it requires businesses to provide warnings if their products expose consumers to significant levels of listed chemicals.

Laboratories measure PAHs using high-performance liquid chromatography (HPLC) or gas chromatography coupled with mass spectrometry (GC-MS).

Guidance for Industry

Food processors can control PAHs in their product by:

  1. Using PAH-free oils and fats
  2. Controlling processing times and temperatures to prevent PAH formation
  3. Incorporating techniques such as indirect heating methods
  4. Utilizing specific additives and coatings to reduce PAH formation on grilled surfaces

Information for Consumers to Reduce Exposure from Food

Consumers can reduce their exposure to PAHs by limiting consumption of roasted or toasted foods, grilled and smoked meats; choosing leaner cuts of meat to reduce the amount of fat dripping and burning; using cooking methods such as boiling, steaming, or microwaving instead of grilling and roasting; raising the grill grate higher over the flames to reduce the amount of charring; and removing blackened portions before consumption.

Resources