PAHs, or polycyclic aromatic hydrocarbons, are formed as a result of incomplete combustion when fossil fuels are used, for example in industry and transport. Atmospheric currents transport them as small particles and they have therefore spread everywhere in nature. PAHs can end up in food as a result of contamination of their raw materials.
PAHs can also be formed in foods as a result of their manufacturing processes. PAHs may occur in particular in products that have been smoked, roasted, barbecued or dried. This means that, depending on their manufacturing methods, PAHs can occur in both industrial and home-made foods.
The European Food Safety Authority EFSA assesses the main sources of PAH in the diet to be cereals and cereal products, as well as various fish and crustacean foods. However, the ways of food consumption and preparation of individual consumers can have a major impact on the most significant sources of exposure.
PAHs usually occur as very complex combinations. The best-known and most harmful of the compounds is benzo[a]pyrene. According to EFSA, benzo[a]pyrene alone is not sufficient to demonstrate the occurrence of PAHs in food. On the other hand, the sum of so-called PAH4 compounds (benzo[a]pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene) is a better indicator for this purpose.
Smoke flavouring means a product obtained by fractionation and purification of condensed smoke. The use of smoke flavourings has generally been considered safer for health than the use of smoke produced by burning wood or heating sawdust or small chips ( EFSA, 2008 ). Used properly, products made using smoke flavourings (so-called liquid smoked foods) contain fewer PAHs than traditionally smoked products. The use of smoke flavourings is regulated and only authorised products may be used. For more information about smoke aromas.
Adverse health effects
Some PAHs are carcinogenic and mutagenic. Currently, 16 PAHs have been identified as carcinogenic. Although PAHs are fat-soluble compounds, they do not accumulate in the body.
The European Food Safety Authority (EFSA) has set the toxicological reference value (BMDL01, benchmark dose limit) for inorganic arsenic at 0.07 mg/kg bw/d. The toxicological reference value (BMDL10) for PAH4s has been set at 0.34 mg/kg bw/d. The values correspond to levels at which the risk of various cancers in the population increases by 10% in the long term compared to a population not exposed to PAHs.
Maximum level in foods
EU legislation ((EC) No 1881/2006 as amended) sets maximum levels for benzo(a)pyrene and the sum of PAH4s for oils and fats, cocoa beans and their products, coconut oil, smoked meat and smoked meat products, smoked muscle meat of fish and smoked fishery products, and heat-treat meat and meat products when sold to the final consumer, smoked bivalve molluscs, processed cereal-based foods and baby foods for infants and young children, infant formulae and follow-on formulae, dietary foods for special medical purposes intended specifically for infants, cocoa fibre and cocoa fibre products, banana chips, certain dietary supplements, dried herbs as well as for dried spices.
Finland has a temporary derogation to allow on its own market traditionally smoked meat and meat products as well as fish and fishery products subject to higher maximum PAH levels (benzo(a)pyrene 5 µg/kg and PAH4 30 µg/kg). The products must be smoked in Finland and they are only allowed for consumption in Finland. In the summer of 2017, the Ministry of Agriculture and Forestry applied on behalf of Finland for a permanent derogation for traditionally smoked meat and meat products and for traditionally smoked small fish and fishery products made from them. The matter is under preparation in the European Commission. In accordance with the Commission's notification, the terms of the temporary derogation will be complied with until the forthcoming decision.