Effect of Combustion Material on the Level of Persistent Organic Pollutants in Smoked Pork

Background: Although smoking has historically been one of the most prevalent methods for food preservation, it was considered a source of carcinogenic and mutagenic persistent organic pollutants (POPs), such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) due to incompletely combustion process. In this study, POPs in pork samples smoked with different materials: sawdust only (NP group), sawdust and polyethylene (PE group), sawdust and polystyrene (PS group), and mixed sawdust (M group) were detected and quantified. Method: The GC-MS method was applied to quantify several POPs in pork samples smoked by various materials. After that, multivariate statistics were used to elucidate differences among groups and chemical markers associated with each smoking material, underscoring the need to evaluate the implications of smoking materials on food safety and public health. Results: The total PAH and PCB contents were lowest in the NP samples (smoked with sawdust only), with PAH levels ranging from 500 to 2000 µg/kg lipid and PCB levels from 0.5 to 1.3 µg/kg lipid. In contrast, the PE, PS, and M groups, which were smoked with sawdust combined with different polymers and contaminants, showed higher levels. The PAH content in these groups exceeded 3000 µg/kg lipid, while PCB levels in PE and PS ranged from 1.5 to over 3.0 µg/kg lipid, and M samples had the widest variation, spanning from 0.6 to 3.2 µg/kg lipid. Regarding PCDD/Fs, none were detected in the NP samples, while the PE and PS groups contained between 1.2 and 1.5 pg/g lipid, with specific compounds identified (e.g., 234678-HxCDF in PE and 12378-PeCDF and 123478-HxCDF in PS). The M samples exhibited the highest PCDD/Fs content, ranging from 5.0 to 14.0 pg/g lipid, with up to six compounds formed, including one PCDD and five PCDFs. Conclusion: The analysis also revealed that the presence of polyethylene and polystyrene significantly elevated POP levels in the respective groups. Meanwhile, samples in the M group possessed various chemical compositions with multiple concentrations, presented by the large area on the PCA biplot and usually intermingled with samples of other groups. Especially, OCDD was the only PCDD that was detected only in M group simples.