# Methods for Determining Polycyclic Aromatic Hydrocarbons (PAHs) in Milk: A Review
## 2 Polycyclic Aromatic Hydrocarbons
### Regulatons of PAHs in the EU and US  
Due to their carcinogenic properties, PAH content limits in food were introduced by the Environmental Protection Agency (EPA) in the United States and the European Food Safety Authority (EFSA) in 2002. The Scientific Committee for Food (SCF) identified 15 genotoxic PAHs out of the 33 tested as priority compounds for assessing dietary PAH intake. Benzo[a]pyrene (BaP) was proposed as a biomarker for monitoring PAH exposure from food and environmental sources [59]. In the EU, the regulation of PAHs in food is covered by Regulation (EU) 2023/915. For PAHs, the regulation sets limits for benzo(a)pyrene and the sum of four PAHs (PAH4), which include benzo(a)pyrene, benzo(a)anthracene, benzo(b)fluoranthene and chrysene. Benzo[a]pirene is highlighted for its high carcinogenicity, and EFSA chose the sum of these four PAHs as a good indicator of the content of PAHs in food products [22; 58]. The SCF evaluated polycyclic aromatic hydrocarbons (PAHs) in food by considering various  
Figure 1: PAH sources in milk [40]. international expert assessments. They prioritized compounds based on potential health risks rather than their prevalence in food. In 2002, the SCF recommended monitoring 15 PAHs, including eight high-molecular-weight ones found on the US EPA list. They identified 15 out of the 33 assessed PAHs, such as benz[a]anthracene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, benzo[a]pyrene, chrysene, cyclopenta[cd]pyrene, dibenzo[a,h]anthracene, dibenzo[a,e]pyrene, dibenzo[a,h]pyrene, dibenzo[a,i]pyrene, dibenzo[a,i]pyrene, dibenzo[a,l]pyrene, dibenzo[a,l]pyrene, indeno[1,2,3-cd]pyrene, and 5-methylchrysene. These compounds have strong evidence of genotoxicity. Besides benzo[ghi]perylene, they also showed definitive carcinogenic effects in several animal bioassays [59; 60] (Figure 2). As a stand-alone product, milk is not listed in the limit ranges for PAHs in EU regulations, but it can be an ingredient in products that already have such limits. Furthermore, regarding the maximum levels for PAHs in infant formula, follow-on formula and food for particular medical purposes intended for infants and young children, these are currently set for products placed on the market without distinction of the product's physical form. Therefore, these maximum levels should be clarified to refer to products ready for use (marketed as such or reconstituted according to the manufacturer's instructions). For the sum of PAHs, the maximum levels refer to the lower-limit concentrations, which are calculated assuming that all the content of the four substances is below the limit of quantification is zero [61]. The EU defined infant formulas, follow-on formulas, and young-child formulas as milk-based drinks and similar protein-based products intended for young children. The maximum level of PAHs applies to the products ready to use (placed on the market as such or after reconstitution as instructed by the manufacturer) [61]. A particular emphasis was placed precisely on children's products due to the daily exposure of children during a period of intensive development and higher sensitivity than adults [62]. Given the reported health effects of exposure to PAHs, it is reasonable to consider implementing additional regulations. Such measures could enhance public safety, particularly given the high consumption of milk and dairy products by vulnerable populations. Monitoring raw milk, as well as products exposed to high temperatures (e.g., pasteurized or sterilized milk, and powdered), could help restrict the distribution of batches with concerning contamination levels. Currently, however, it remains challenging to assess the safety of commercially available products other than those specifically designed for infants. In the US, the Food and Drug Administration (FDA) monitors the regulation of PAHs in food. The FDA has established guidelines and action levels for contaminants, including PAHs, under the Federal Food, Drug, and Cosmetic Act (FFDCA).