Purpose: The purpose of our study was to determine the polyaromatic hydrocarbon (PAHs) residue content in smoked fish and relate this to the antimicrobial properties of partially and fully smoked fish, respectively.
Methods: Commercial smoked salmon were purchased from local grocers (cold-smoked; < 43°C). Half-smoked (2 - 3 days) and fully-smoked (5 - 6 days) salmon were obtained from Tl’azt’en and Lieidli T’enneh First Nations communities and previously smoked at temperatures greater than 85°C. PAH measurements were performed by GC-MS, using authentic standards with detection limits within 1ng/g. Fish fatty acids were measured by GC-FID. The lipid peroxides were measured using the ferrous oxidation-xylenol orange (FOX) assay. Antimicrobial property of PAHs against Listeria innocua was tested in brain-heart infusion broth. A disk diffusion assay was also used to test the antimicrobial activity of hexane extracts recovered from smoked commercial and First Nations’ fish samples.
Results: PAHs were not detected in commercial cold smoked fish; in contrast to First Nations’ fully smoked salmon, which had significantly (P < 0.05) higher levels of both low and high molecular weight PAHs. PAHs recovered from half-smoked fish were low molecular weight. Salmon processed using First Nations’ methods exhibited significantly reduced lipid peroxides and enhanced retention of EPA and DHA (P < 0.05). The generation of low molecular weight PAH’s generated from partial and full smoking of fish significantly increased lag-phase and lowered maximum growth (P < 0.05) of Listeria innocua.
Significance: These data suggest that risks associated with PAH contamination of salmon, derived from First Nations’ smoke preservation methods, also provide benefits of retained nutritional value and antimicrobial activity.