## 4 PAH Occurrence and Formation in Processed Meat, Edible Oils, and Cereal-Derived Products
### Features Underlying PAH Formation in Edible Oils  
The relatively high PAH concentrations (ug/kg) detected in edible oils account for approximately 50% of dietary exposure. It is attributed to their extensive use in cooking, seasoning, and margarines, as well as their incorporation into cereal-based products (e.g., cakes and biscuits) [2; 174; 175]. In the food chain, the main causes of PAH occurrence in vegetable oils include cultivation with contaminated soil and water, the presence of mineral oil residues, and soil burning [2]. In addition, contamination during solvent extraction and the contamination of packaging materials also foster the formation of PAHs [175]. Moreover, the steps involved during processing, such as artificial drying and roasting of seeds and raw materials, seed dewaxing or grinding, and pomace compression, are factors contributing to PAH contamination in crude oil [2; 176; 23; 177]. Figure 5 provides an overview of the important properties modulating PAH levels in edible oils undergoing thermal processing. Further, corresponding factors involved in PAH formation and occurrence are presented and discussed. Figure 5: Flowchart showing the representative factors influencing PAH formation in edible oils undergoing thermal processing. The analysis of raw peanuts and the corresponding crude oil revealed higher PAH content in pressed oil than in solvent-extracted oil (leached). Moreover, due to the temperature applied during roasting, hot-pressed oil results in more abundant PAHs than cold-pressed oil [178]. Similarly, roasting olive fruits results in a significantly higher PAH content in olive oil [13; 179]. The occurrence of PAHs in extra virgin olive oil (EVOO) is generally fairly low and mainly accounts for the environmental load. With lower sensory quality than EVOO and no additional treatment besides mechanical processing, virgin olive oil (VOO) contains comparable PAH levels to EVOO. However, despite undergoing refining steps, olive oil (OO) (consisting of various blends of refined OO and VOO) and olive pomace oil (OPO) contain higher PAH levels than EVOO [180]. Among vegetable oils collected from Egypt, canola oil showed a higher residual PAH concentration than corn, olive, and sunflower oils extracted by cold-pressing. Moreover, heat treatment of canola oil (pan-fried at 180 \({}^{\circ}\)C for 15 min) resulted in a significant increase in PAH levels [91]. In this context, in contrast to crude oils, refining and purification result in considerably lower to non-detectable levels of PAHs in refined oils [114; 120; 175; 181; 182]. For example, PAH levels in sunflower oil throughout processing resulted in decreased contamination upon neutralization (32.02%), bleaching (54.14%), or deodorization (71.77%) compared to the crude oil. Moreover, soybean oil showed comparable refining yields for both bleaching and neutralization (32%), whereas deodorization led to more than an 80% reduction in both soybean and olive oils, respectively [182]. The differences in PAH removal capacity might be attributed to the efficiency variations among activated charcoal and activated earth [182]. Similarly, Brazilian soybean oil registered up to 88% reduction in PAH levels during the refining steps (neutralized, bleached, and deodorized oils) [181]. To this end, notable importance is given to reducing the contamination of oils with OPAHs [114]. Correspondingly, [PERSON] et al. (2016) revealed a significant reduction in total PAH levels in refined soybean oil (59.54%) and rapeseed oil (54.63%). Concomitantly, declines in OPAHs obtained for soybean and rapeseed oils through refining reached 89.82% and 69.05%, respectively [114]. Similarly, olive oil investigated throughout the refining steps rendered neutralization 90% effective in decreasing the total PAH concentration. Moreover, altering the proportion of activated carbon during bleaching from 0.3% to 0.9% resulted in a reduction in PAH content from 86% to 91% [183].