Why is it always said that "barbecue should be eaten sparingly, as frequently eat barbecue is not good for the body; smoking is prohibited in public places, as smoking is harmful to health", which has a common risk factor is - polycyclic aromatic hydrocarbons (PAHs). Due to genotoxicity, mutagenicity and carcinogenicity, the PAHs can cause a variety of hazards to human body , such as damage to the respiratory system, circulatory system, nervous system, liver, and kidney , recognized as the main organic pollutants affecting human health. In this article, Foodmate will take you to understand what are PAHs, the harm of PAHs to human body and the current regulatory requirements of PAHs in various countries.

1. What are PAHs

Polycyclic Aromatic Hydrocarbons (PAHs) are hydrocarbons that contain two or more benzene rings in their molecules. The main sources of PAHs in food are grains, vegetables, fats and oils, and commonly barbecued meats. Processing methods such as baking and grilling will generate more PAHs and thus increase the level of PAHs in food; and charred food contains more PAHs, so people who love to eat barbecued meat may consume more PAHs.

PAHs can be categorized into four groups according to their molecular structure and chemical properties:

(1) Compounds with a thickened polybenzene structure, such as trisubenzene, dibenzo[e,i]pyrene, tetrabenzo[a,c,h,j]anthracene, etc., which have similar chemical stability to benzene;

(2) Polycyclic aromatic hydrocarbons arranged in a straight line, such as anthracene, butyl and pentyl provinces, are much more chemically active than benzene.

(3) Polycyclic aromatic hydrocarbons in angular arrangement, such as phenanthrene, benzo[a]anthracene, naphtho[2,3-a]anthracene, anthraceno[2,3-a]anthracene, etc., are generally less chemically active than the corresponding isomers in linear arrangement.

(4) Thick cyclic hydrocarbons with more complex structures such as benzo[a]pyrene, dibenzo[a,i]pyrene, etc., have active mesophenanthrene bonds but no active para-positions.

2. Hazards of polycyclic aromatic hydrocarbons to humans

PAHs enter the human body through the respiratory tract, skin, and digestive tract during their generation, migration, transformation, and degradation, which greatly threaten human health and have strong teratogenic, carcinogenic, and mutagenic effects. Ingested PAHs are absorbed by the body through the gastrointestinal tract, and then distributed to all parts of the body, including almost all organs in the body.The metabolism of PAHs is complex, in simple terms, PAHs are transformed through the process of metabolism into a product that is excreted from the body, or formed into a metabolite that has an activity, which eventually binds to Deoxyribonucleic Acid (DNA) and becomes a covalent adduct compounds. Since the appearance of DNA addition compounds is considered to be the initial stage of chemical carcinogenesis, the appearance of active metabolites is considered to be closely related to the carcinogenesis of PAHs. Benzo[a]pyrene is classified by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) as one of the PAHs as "carcinogenic to humans" (i.e., Group 1), and three other PAHs (cyclopenta[c,d]pyrene, dibenzo[a,l]pyrene, and dibenzo[a,h]anthracene) are classified as "possibly carcinogenic to humans" (i.e. Group 2A).

3. National regulation of PAHs

(1) China

GB 2762-2022 "National Food Safety Standard Maximum Levels of Contaminants in Foods" stipulates the limits of benzo[a]pyrene, which are 2.0 μg/kg for grains and their products: paddy (in terms of brown rice), brown rice, rice (flour), wheat, wheat flour, maize, maize flour, maize grits (dregs), and 5.0 μg/kg for meat and its products: smoked, broiled, roasted meat and aquatic products. Animals and their products: the limit of benzo[a]pyrene in smoked and roasted aquatic products is 5.0 μg/kg, and the limit of benzo[a]pyrene in milk and dairy products, including thin cream, cream, anhydrous cream and fats and oils and their products, is 10.0 μg/kg.

(2) CAC

Regarding the control measures for PAHs in food, CAC formulated the "Code of Practice for the Reduction of Contamination by Polycyclic Aromatic Hydrocarbons (PAH) in Food from Smoking and Direct Drying Processes" in 2009, which provides guidance for national and local authorities, producers and other stakeholders to independently review and improve their processing operations based on the Code of Practice, in order to minimize the risk of contamination of food products with PAHs.

(3) European Union

On May 5, 2023, the Official Journal of the European Union (OJEU) announced that the European Commission issued Regulation (EU) 2023/915, which sets new standards for contaminant limits in food, replacing Regulation (EC) No 1881/2006. The new version of the standard canceled the maximum limit of PAHs in instant/soluble coffee products, and clarified that the maximum limit of PAHs in infant formula and formulae for special medical purposes for infants and young children is only applicable to products in ready-to-eat state. The specific limit requirements are shown in the table below:

(4) United States

Part 165 of Title 21 of the U.S. Code of Federal Laws, which stipulates that the limit of benzo(a)pyrene in bottled water is 0.0002 mg/L.

(5) Japan

No limit value for PAHs in food has been established and they are contaminants in food that need attention.

(6) Korea

The Codex Alimentarius of Korea provides relevant provisions for benzo(a)pyrene in 11 types of products. Among them, the limit of benzo[a]pyrene is 1.0 μg/kg in foods for special purposes (infant formula milk products, follow-up formula milk products, infant formula, follow-up formula, complementary foods for infants and young children, special formula for infants and young children), the limit of benzo[a]pyrene in black ginseng (including powder), fish oil, fish oil, other animal fats and oils, mixed edible oils, flavored oils, processed fats and oils, shortening, margarine) is 2.0 μg/kg, the limit of benzo[a]pyrene in black ginseng concentrate is 4.0 μg/kg, the limit of benzo[a]pyrene in smoked meat and its processed products, mollusks (except shellfish) and crustaceans, smoked fish, cooked and dried huangdi is 5.0 μg/kg, and the limit of benzo[a]pyrene in shellfish and smoked and dried fish is 10.0 μg/kg.

Summary

The issue of polycyclic aromatic hydrocarbons (PAHs) as food contaminants has attracted worldwide attention, and many countries are actively formulating and implementing relevant policies and standards to control the levels of PAHs in food in order to protect consumers' health. Foodmate reminds relevant enterprises to pay attention to the pollution of PAHs during the production process. Meanwhile, Foodmate will continue to pay attention to the changes of relevant policies and regulations, and share the important information for the industry in a timely manner.