Concentration of polycyclic aromatic hydrocarbons (PAHs) in bread and health risk assessment across the globe: A systematic review and meta-analysis

Although bread is the principal food in most countries, polycyclic aromatic hydrocarbons (PAHs) may be present and pose a potential risk to consumers. The aim of this review is to provide a comprehensive report on the concentration and health risks associated with PAHs in bread around the world. Various databases, such as Scopus, PubMed, Science Direct, and Google Scholar, were searched from their beginnings until December 2023 for this systematic review, which included 34 potentially relevant articles with data relating to 1057 bread samples. Utilizing a multilevel regression modeling approach, the study evaluated various factors such as fuel type, bread type, and geographical location. Following the initial evaluation, in 26.47% and 20.28% of all studies, the levels of Bap and PAH4 were higher than the permissible limit values, respectively. Based on the isomer ratios, 55.88% of the studies associated the presence of PAHs in bread samples with pyrogenic/coal combustion sources. According to the carcinogenic risk results, bread consumers in all studies have been exposed to moderate or high levels of carcinogenicity. The most significant risk levels are associated with the consumption of bread in Egypt, Kuwait, Iran, and India. Moreover, meta-regression analysis demonstrated significantly higher toxicity equivalent quotient and cancer risk mean values in bread baked using fossil fuels compared to other sources (p < .05). The high concentrations of PAHs, especially Benzo[a]pyrene, in bread pose a serious public health risk. Stringent regulations and monitoring are crucial to reduce contamination. Further research is necessary to develop safe processing methods to remove PAHs in bread.