We evaluated the performance of a gas chromatography–tandem mass spectrometry method for quantifying 16 polycyclic aromatic hydrocarbons (PAHs), which the Scientific Committee on Food and the Joint Food and Agriculture Organization of the United Nations/World Health Organization Expert Committee on Food Additives have considered to be of concern to human health and used the method to determine the PAH concentrations in smoked foods. Eighty-seven samples of smoked fish, smoked meat, smoked eggs, dried bonito flakes, and dried bonito–related soup-stock products (disposable powder packets for infusion, instant bouillons, and liquids) were purchased in Japan to analyze their content of the 16 PAHs. Because of the low certainty of some results, the analytical values for some PAHs (e.g., benzo[c]fluorene, chrysene, and dibenzo[a,h]pyrene) are given for informational purposes only. The highest median concentrations of benzo[a]pyrene and the sum of all the 16 PAHs (29 and 760 μg/kg, respectively) were found in the disposable powder packets, followed by dried bonito flakes (24 and 512 μg/kg, respectively), and instant bouillons (11 and 227 μg/kg, respectively). These concentrations were much higher than those in the other products tested. We also investigated the percentages of the PAHs transferred from dried bonito flakes and a disposable powder packet to soup stocks commonly prepared at home. These were extremely low (<4%), even though they contained relatively high concentrations of the PAHs. Finally, the intake of benzo[a]pyrene and the sum of the intakes of four PAHs, as a marker proposed by the European Food Safety Authority, were estimated based on the data from a Japanese food consumption survey and the mean concentrations found in smoked fish and smoked fish products. These estimates suggest intakes of PAHs pose a low concern for consumer health. HIGHLIGHTS

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Summar y2-dodecylcyclobutanone (DCB) and 2-tetradecylcyclobutanone (TCB) are specific radiolytic products in irradiated lipid-containing food and can be used to detect irradiation of foodstuffs. Here, we evaluated a rapid shaking extraction method to detect irradiation in beef, pork, chicken and salmon. The amounts of DCB and TCB extracted by the shaking extraction method were 77-121% of those by the conventional Soxhlet extraction method in irradiated meats and salmon. The selected ion-mode chromatograms of DCB and TCB obtained from both extractions were visually inspected, but showed no significant differences. These results suggest that the shaking extraction method achieved similar extraction efficiencies for DCB and TCB to the Soxhlet extraction method. Finally, we used the shaking extraction method to detect irradiation in beef, pork, chicken and salmon irradiated at 0.5 kGy or 1 kGy. All of the non-irradiated samples were judged negative and all of the irradiated samples were judged positive. Overall, our results indicate that the shaking extraction is a useful method for extracting DCB and TCB from meats and salmon. The main advantage of this method is the short extraction time (approximately 1 h), thereby allowing rapid detection of irradiated meats and salmon.