Polycyclic Aromatic Hydrocarbons

They consist of carbon and hydrogen and are a group of relatively stable lipophilic organic substances containing two or more aromatic rings. Hydrocarbons are organic compounds consisting of carbon and hydrogen. The term aromatic refers to the compound containing a cyclic structure as typified by benzene and ‘poly’ refers to two or more aromatic rings, the presence of which gives these compounds enhanced stability.
There are over 600 known PAH structures. The most commonly known are those of public health significance.
Generally, PAH tend to have a high melting and boiling point with low vapour pressure and low water solubility. They are lipophilic and accumulate in lipid tissue over time.

The main routes of exposure are through the environment, food processing and preparation.
The introduction of PAH into food from the environment can occur through a wide variety of sources including stubble burning, motor vehicle and aircraft exhausts, industrial plants, wood preservation, domestic heating, tyre burning, tobacco smoke, oil pollution, forest fires, and volcanoes.
Raw unprocessed foods should not contain significant levels unless there has been environmental contamination.
Processing and heating of foods are major sources of PAH introduction. PAH have been found in a wide variety of foods including smoked meat and fish, barbecued meat, and vegetable oils. Levels found tend to be linked to the amount of fatty tissue, temperature, and duration of heating.

Due to their negative public health impact and historical levels of occurrence in certain food groups, PAH are classified as contaminants and regulated under retained EU Regulation 1881/2006. Maximum regulatory levels have been established for foods intended to be placed on the market. High levels of PAH in a food would lead to that specific food not meeting the food safety requirements as set out in retained EU Regulation 178/2002.
For more information on current regulatory levels, refer to the Contaminants in Food (England) Regulations 2013 and Section 6 of the Annex to retained EU Regulation 1881/2006. Section 6 names the specific foodstuffs covered by the maximum levels and lists the levels that apply. 
Each foodstuff must comply with two maximum levels: the maximum level of benzo(a)pyrene and the maximum level of the sum of the four substances benzo(a)pyrene, benzo(a)anthracene, benzo(b)fluoranthene and chrysene, known collectively as PAH4. The PAH4 level became the parameter of choice following EFSA’s publication of a Scientific Opinion in 2008. According to that Opinion, PAH4 was a more suitable indicator of PAH contamination than the previous marker, which was benzo(a)pyrene alone. The separate maximum level for benzo(a)pyrene was retained to ensure comparability of previous and future data, but this may be reassessed in the future.

In HACCP, one must assess the likelihood of PAH being present, introduced, or developing. Where a hazard does exist, ensure controls are in place to meet regulatory limits as they are considered a chemical hazard.
In cases where PAH are found in raw material streams or formed during processing, operations may be reviewed and redesigned to minimize their presence and/or formation.
Removal of the outer layer of vegetables and fruits and washing can reduce PAH levels, as concentrations tend to be higher on the external tissue when present.
PAH can be introduced from environmental sources, during direct drying and smoking operations. Codex has produced a code of practice for the reduction of contamination of food with PAH from smoking and direct drying processes.