July 2022
The purpose of this document is to provide an overview of Polycyclic Aromatic Hydrocarbons, their formation and occurrence in foods, public health significance, legislation, methods of detection, and industry good practices.
Further background and information can be found in the references.
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.
PAH are primarily formed during incomplete combustion or breakdown of organic matter at high temperatures and during various industrial processes. They can also be formed in natural processes such as carbonisation.
In food preparation, they may be formed in a number of processing and domestic preparation steps including grilling (e.g. on a barbecue), roasting, smoking, drying, baking, frying, and toasting.
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.
Many PAH have been shown to exhibit immunotoxicity, genotoxicity, reproductive toxicity, carcinogenicity, and may influence the development of atherosclerosis.
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.
The accepted methods of sampling and analysis are laid down in retained EU Regulation 333/2007 (9). Sampling methodology is important in order to ensure representative samples are taken which will lead to meaningful results. The method of analysis must meet the specific requirements of the performance criteria as defined in table 7 (Performance criteria for methods of analysis for benzo(a)pyrene) of that regulation.
When performing analysis for official control purposes, the "fitness-for-purpose" approach may be used to assess the suitability of the method of analysis. Methods suitable for official control must produce results with standard measurement uncertainties less than the maximum standard measurement uncertainty calculated using the formula in section C.3.3.2 of retained EU Regulation 333/2007.
Part D of that regulation covers the reporting and interpretation of results.
There are various methods of detection in the marketplace for PAH analysis.
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.
1. IUPAC Gold Book http://goldbook.iupac.org/
2. National Institute of Standards and Technology The NIST Polycyclic Aromatic Hydrocarbon Structure Index
3. EFSA Evaluation of public health significance http://www.efsa.europa.eu/en/efsajournal/pub/724.htm
4. WHO evaluation on health http://www.euro.who.int/__data/assets/pdf_file/0015/123063/AQG2ndEd_5_9P...
5. JECFA evaluation http://www.inchem.org/documents/jecfa/jeceval/jec_1941.htm
6. EFSA Occurrence of PAH in food supplements EURL 2014 PT PAH in food supplements (europa.eu)
7. EU regulatory Contaminants Retained EU regulation 1881/2006. https://ec.europa.eu/food/safety/chemical-safety/contaminants_en
8. The Contaminants in Food (England) Regulations 2013 https://www.legislation.gov.uk/uksi/2013/2196/contents/made
9. Accepted methods of sampling and analysis laid down in retained EU regulation 333/2007.
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2007:088:0029...
10. CODEX Code of practice for the reduction of contamination of food with PAH from smoking and direct drying processes. https://www.fao.org/fao-who-codexalimentarius/sh-proxy/en/?lnk=1&url=htt...
Institute of Food Science & Technology has authorised the publication of this Information Statement on Polycyclic Aromatic Hydrocarbons
This is an update to the Information Statement that has been prepared by Sarah Howarth FIFST in 2015. It has been peer-reviewed and approved by the IFST Scientific Committee and is dated July 2022.
The Institute takes every possible care in compiling, preparing and issuing the information contained in IFST Information Statements, but can accept no liability whatsoever in connection with them. Nothing in them should be construed as absolving anyone from complying with legal requirements. They are provided for general information and guidance and to express expert professional interpretation and opinion, on important food-related issues.