{"@context":{"@language":"en","Affiliation":"http:\/\/vivoweb.org\/ontology\/core#departmentOrSchool","AggregatedSourceRepository":"http:\/\/www.europeana.eu\/schemas\/edm\/dataProvider","Citation":"https:\/\/open.library.ubc.ca\/terms#identifierCitation","Creator":"http:\/\/purl.org\/dc\/terms\/creator","DateAvailable":"http:\/\/purl.org\/dc\/terms\/issued","DateIssued":"http:\/\/purl.org\/dc\/terms\/issued","Description":"http:\/\/purl.org\/dc\/terms\/description","DigitalResourceOriginalRecord":"http:\/\/www.europeana.eu\/schemas\/edm\/aggregatedCHO","FullText":"http:\/\/www.w3.org\/2009\/08\/skos-reference\/skos.html#note","Genre":"http:\/\/www.europeana.eu\/schemas\/edm\/hasType","IsShownAt":"http:\/\/www.europeana.eu\/schemas\/edm\/isShownAt","Language":"http:\/\/purl.org\/dc\/terms\/language","PeerReviewStatus":"https:\/\/open.library.ubc.ca\/terms#peerReviewStatus","Provider":"http:\/\/www.europeana.eu\/schemas\/edm\/provider","Publisher":"http:\/\/purl.org\/dc\/terms\/publisher","PublisherDOI":"https:\/\/open.library.ubc.ca\/terms#publisherDOI","Rights":"http:\/\/purl.org\/dc\/terms\/rights","RightsURI":"https:\/\/open.library.ubc.ca\/terms#rightsURI","ScholarlyLevel":"https:\/\/open.library.ubc.ca\/terms#scholarLevel","Subject":"http:\/\/purl.org\/dc\/terms\/subject","Title":"http:\/\/purl.org\/dc\/terms\/title","Type":"http:\/\/purl.org\/dc\/terms\/type","URI":"https:\/\/open.library.ubc.ca\/terms#identifierURI","SortDate":"http:\/\/purl.org\/dc\/terms\/date"},"Affiliation":[{"@value":"Land and Food Systems, Faculty of","@language":"en"},{"@value":"Non UBC","@language":"en"}],"AggregatedSourceRepository":[{"@value":"DSpace","@language":"en"}],"Citation":[{"@value":"Kitts, D.D.; Pratap-Singh, A.; Singh, A.; Chen, X.; Wang, S. A Risk\u2013Benefit Analysis of First Nation\u2019s Traditional Smoked Fish Processing. Foods 2023, 12, 111.","@language":"en"}],"Creator":[{"@value":"Kitts, David D.","@language":"en"},{"@value":"Pratap-Singh, Anubhav","@language":"en"},{"@value":"Singh, Anika","@language":"en"},{"@value":"Chen, Xiumin","@language":"en"},{"@value":"Wang, Siyun","@language":"en"}],"DateAvailable":[{"@value":"2023-09-19T22:36:27Z","@language":"en"}],"DateIssued":[{"@value":"2022-12-26","@language":"en"}],"Description":[{"@value":"First Nations (FN) communities have traditionally used smoke to preserve fish for food security purposes. In this study, an assessment of chemical and microbiological food safety, together with nutritional quality, was conducted on fish preserved using traditional smoke processing. High-molecular-weight polycyclic aromatic hydrocarbons (PAH) residues accounted for only 0.6% of the total PAH in traditionally fully smoked salmon, and Benzo(a)pyrene (B(a)P) was not detected in the FN smoked or commercial smoked fish, respectively. The antimicrobial activity of the solvent extracts derived from smoked fish towards Listeria innocua was very low but detectable. The practice of using full and half-smoked processing for fish reduced all of the fatty acid concentrations and also minimized the further loss of essential omega-3 fatty acids to a greater extent than non-smoked fish during storage (p < 0.05). This finding corresponded to lower (p < 0.05) lipid oxidation in smoked fish. We conclude that the benefits of reducing lipid oxidation and retaining essential fatty acids during storage, together with a potentially significant reduction in Listeria contamination, are notable benefits of traditional smoke processing. Although B(a)P was not detected in FN smoked fish, attention should be given to controlling the temperature and smoking period applied during this processing to minimize potential long-term risks associated with PAH exposure.","@language":"en"}],"DigitalResourceOriginalRecord":[{"@value":"https:\/\/circle.library.ubc.ca\/rest\/handle\/2429\/85969?expand=metadata","@language":"en"}],"FullText":[{"@value":"Citation: Kitts, D.D.; Pratap-Singh,A.; Singh, A.; Chen, X.; Wang, S. ARisk\u2013Benefit Analysis of FirstNation\u2019s Traditional Smoked FishProcessing. Foods 2023, 12, 111.https:\/\/doi.org\/10.3390\/foods12010111Academic Editor: Eva Mar\u00edaDom\u00e9nech AntichReceived: 12 November 2022Revised: 1 December 2022Accepted: 10 December 2022Published: 26 December 2022Copyright: \u00a9 2022 by the authors.Licensee MDPI, Basel, Switzerland.This article is an open access articledistributed under the terms andconditions of the Creative CommonsAttribution (CC BY) license (https:\/\/creativecommons.org\/licenses\/by\/4.0\/).foodsArticleA Risk\u2013Benefit Analysis of First Nation\u2019s Traditional SmokedFish ProcessingDavid D. Kitts 1,* , Anubhav Pratap-Singh 1 , Anika Singh 2, Xiumin Chen 3 and Siyun Wang 11 Food Science, Food Nutrition and Health, Faculty of Land and Food Systems,The University of British Columbia, Vancouver, BC V6T 1Z4, Canada2 NHP Research Group, Centre for Applied Research and Innovation (CARI), British Columbia Institute ofTechnology, Burnaby, BC V5G 458, Canada3 School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China* Correspondence: david.kitts@ubc.ca; Tel.: +1-(604)-822-5560Abstract: First Nations (FN) communities have traditionally used smoke to preserve fish for foodsecurity purposes. In this study, an assessment of chemical and microbiological food safety, togetherwith nutritional quality, was conducted on fish preserved using traditional smoke processing. High-molecular-weight polycyclic aromatic hydrocarbons (PAH) residues accounted for only 0.6% of thetotal PAH in traditionally fully smoked salmon, and Benzo(a)pyrene (B(a)P) was not detected inthe FN smoked or commercial smoked fish, respectively. The antimicrobial activity of the solventextracts derived from smoked fish towards Listeria innocua was very low but detectable. The practiceof using full and half-smoked processing for fish reduced all of the fatty acid concentrations and alsominimized the further loss of essential omega-3 fatty acids to a greater extent than non-smoked fishduring storage (p < 0.05). This finding corresponded to lower (p < 0.05) lipid oxidation in smoked fish.We conclude that the benefits of reducing lipid oxidation and retaining essential fatty acids duringstorage, together with a potentially significant reduction in Listeria contamination, are notable benefitsof traditional smoke processing. Although B(a)P was not detected in FN smoked fish, attentionshould be given to controlling the temperature and smoking period applied during this processing tominimize potential long-term risks associated with PAH exposure.Keywords: First Nation\u2019s smoke processing; safety; nutritional quality; fish; lipid oxidation1. IntroductionFish and fish products represent an important food staple in the diet of First Nationcommunities that live in rural Northern Canada. The use of smoke processing for fishand seafood continues to be practiced as a traditional method of preservation in NorthAmerican First Nation communities [1,2]. Smokehouses typically use hot smoke generatedby burning wood on an open fire to directly expose fish to both smoke and heat overvarying time periods. In British Columbia, Canada, First Nation communities categorizesmoked fish products based on the length of the smoking time; with partially smoked fishrequiring 2\u20133 days compared to fully smoked fish, which can take up to 5\u20136 days [2]. Theseproducts are considered ready-to-eat (RTE) and are used in a manner similar to commercialsmoked RTE fish that has been processed using low heat.The traditional smoke processing used by First Nations communities involves directsmoking, whereby fish are placed above a heat source (e.g., a wood source, such as pineand birch) to generate smoke without controlling for the heat intensity or smoke expo-sure [2,3]. The potential concerns of using this hot smoke process include the combinationof high temperature and the inherent unique lipid compositional properties of the fishthat can potentially produce undesirable by-products, such as polycyclic aromatic hydro-carbons (PAHs) [4\u20136]. The direct pyrolysis of fat melting onto the heat source, togetherwith the smoke produced from the incomplete combustion of the wood used to generateFoods 2023, 12, 111. https:\/\/doi.org\/10.3390\/foods12010111 https:\/\/www.mdpi.com\/journal\/foodsFoods 2023, 12, 111 2 of 14heat, collectively produces PAHs that accumulate mostly on the outside of the fish [7].Symptoms of short-term exposure to PAHs can include skin and eye irritation and immune,reproductive, and developmental toxicities [8]. In contrast, long-term exposure to fifteendifferent PAHs, of which eight are high-molecular-weight isoforms, has raised concerns ofgenotoxicity, mutagenicity and carcinogenesis [9\u201311]. Regulatory bodies have designatedBenzo(a)pyrene (B(a)P) as a marker of the occurrence of carcinogenic PAH in food in orderto evaluate the PAH contamination of commodities, whereas other PAHs that are notidentified as carcinogens may act as synergists [12]. B(a)P residues have been reported toexceed the set limits of 5 \u00b5g\/kg [9] when processed with different durations of smoking andusing different wood sources [13]. In our previous study, we detected only trace amounts(<5 \u00b5g\/kg) of B(a)P in fully smoked fish [2].Another concern related to RTE fish products is the risk posed by exposure to food-borne pathogens, mainly Listeria monocytogenes [14]. It is noteworthy that raw salmon isnot so much the source of L. monocytogenes compared to the significance of the process-ing environment and hygienic practices that result in the recontamination of the productwith Listeria sp. [15]. We reported that the preservation methods used by the First Na-tions showed no signs of L. monocytogenes, albeit the presence of microorganisms thatsignaled breaks in hygiene was noted [16]. In a former study, we also showed that theextracts derived from smoked fish were effective at controlling the growth of Staphylococcusaureus [17].Salmon is a major food source harvested by First Nations communities in B.C. Thenutritional benefits associated with salmon consumption include its high-quality proteincontent and that it is also an excellent source of highly polyunsaturated fatty acids (HUFAS),especially docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids [18,19]. These twoimportant HUFAs have been attributed to numerous health benefits that include preventingcardiac arrhythmia (ventricular tachycardia and fibrillation) and sudden death, as wellas anti-thrombotic functions, which is a known factor linked to reducing myocardialinfarction [20,21]. Moreover, EPA and DHA have well-recognized cognitive benefits thatinclude improving attention deficit hyperactivity disorder, dyslexia, and depression andhave a positive contributing effect on child IQ scores at 4 years of age [22,23]. However, aftercatching fish, the susceptibility of HUFAS to lipid oxidation can represent a potential foodsafety and health risk issue that involves the hydrolytic degradation and autooxidation ofHUFA during storage, which not only lowers the nutritional value of the fish products but isalso a source of unwanted lipid oxidation products [24\u201327]. Thus, reducing lipid oxidationreactions through effective processing is vital to retaining the safety and nutritional valueof the salmon consumed by First Nations communities.The purpose of this study was to investigate the effects of traditional FN smokepreservation methods on potential PAH formation, along with quantifying the losses inthe nutritional value of the lipid content in smoked fish. By measuring both the chemicaland microbiological parameters, we attempted to provide a more descriptive risk\u2013benefitanalysis of using traditional smoke processing to preserve fish than previously reported.2. Materials and Methods2.1. Sample Collection and PreparationFish, in this case, salmon, were collected by four First Nation communities in North-ern B.C. and smoked in similar smokehouses using the protocols reported in our earlierstudies [2,16]. Briefly, prior to smoking, all of the fish were fileted and salted. The treat-ments consisted of fish that were half-smoked (n = 6) for later use as canned products andfully smoked (n = 6), which no longer required further processing. The non-smoked controlfish (n = 6) were also obtained from the FN communities. In addition, three commercial-smoked salmon samples (Finest at Sea Ocean Products Ltd., Vancouver, BC, Canada) werepurchased to be included for the qualitative comparisons only. The actual time periods usedto smoke the fish, thus distinguishing between the partially and fully smoked products,were the same as described previously [2], this being 2\u20133 days and 5\u20136 days, respectively.Foods 2023, 12, 111 3 of 14The samples of smoked fish were stored in re-sealable Ziploc bags on ice and delivered tothe Food, Nutrition and Health Building, located on the Point Grey University of BritishColumbia campus, Vancouver, British Columbia. The samples were obtained within 48 hof shipping. Upon receipt of the samples, the fish were thawed and homogenized using acommercial blender (Waring, Stamford, CT, USA) and then stored at \u221220 \u25e6C until ready forfurther analyses.2.2. Moisture MeasurementThe moisture content of the fish samples was determined according to publishedmethods [28]. Each treatment was performed in triplicate.2.3. Sodium and Potassium AnalysisThe samples were measured for sodium and potassium using ICP-MS (MaxxamAnalytics, Burnaby, BC, Canada) and expressed on a dry-weight basis [16].2.4. Polyaromatic Hydrocarbon (PAH) AnalysisThe PAH analysis of the homogenized samples was conducted by Maxxam Analytics(Burnaby, BC, Canada). The homogenized fish (5 g freeze dried) and a methanol blank werespiked with a surrogate standard mixture containing 4 deuterated PAHs. The samples wereextracted with 100% dichloromethane (DCM) at 100 \u25e6C at a pressure of 2000 psi (Dionex\u2014model 2000). The DCM extracts were passed through a sodium sulfate column to removeresidual water and then exchanged into hexane. The hexane extracts were transferred toa fully activated silica gel clean-up column and eluted with 40 mL of hexane, followedby 70 mL of 50% DCM in hexane. The polycyclic aromatic hydrocarbon was recovered iniso-octane and concentrated before adding the internal 3 pre-deuterated PAH standards.Samples were analyzed by GC-MS (Agilent 6890 gas chromatograph equipped with aModel 5973 mass selective detector). A GC capillary fused silica column (Agilent HP-5ms;a length of 30 m, an inner diameter of 0.025 mm, and a film thickness of 0.25 \u00b5m) was used.The samples were injected (2 \u00b5L) in the pulsed split-less mode with an initial pressure of25 psi held for 1.2 min and then maintained a constant flow of 1.2 mL\/min. The columntemperature was programmed as follows: 80 \u25e6C (2 min), 80\u2013100 \u25e6C (50 \u25e6C\/min), 100\u2013300 \u25e6C(5 \u25e6C\/min), and 300 \u25e6C (5 min). The injector temperature was set to 260 \u25e6C, the transfer lineto 300 \u25e6C, and the ion source and quadrupole to 230 \u25e6C and 106 \u25e6C, respectively. Heliumwas used as the carrier gas. Two ions were monitored for each analyte and per-deuteratedPAH standards. The PAH content was determined based on a 5-point calibration curve thatwas checked after every 6 injections for continuing performance. Authentic standards wereused to generate the relative response factor for the PAH. The detection limits and percentrecovery of individual PAHs varied with specific compounds but was less than 1 ng\/g,with recoveries ranging from 70\u201385% [2]. To obtain an estimate of the toxic potency of thePAHs in the smoked fish samples, we calculated a total PAH benzo(a)pyrene equivalentaccording to the equation [29]:BaP eqi =\u2211 (BaP eqi) =\u2211 (CPAHi \u00d7 TEFPAHi) (1)where BaP eqi value represents each PAH from the concentration samples (C) multipliedby the toxic equivalency factor (TEF), derived from Supplementary Table S1 [30].2.5. Fatty Acid AnalysisThe total crude lipids were recovered from the fish extracted in duplicate usingFolch\u2019s method consisting of chloroform: methanol (2:1 v\/v), containing 0.01% butylatedhydroxytoluene (BHT) as the antioxidant [31]. Fatty acid methyl esters (FAME) wereprepared from the total crude lipids by transesterification with Boron trifluoride (BF3)in methanol [32]. An internal standard (tricosanoic acid methyl ester, C23:0, 10 mg\/mLsolution) was added to the sample for the quantification analyses. FAMEs were extracted inhexane and analyzed using gas chromatography (GC-17A, Shimadzu Scientific InstrumentsFoods 2023, 12, 111 4 of 14Inc., Columbia, MD, USA) equipped with a flame ionization detector and an auto-injector(AOC1400, Shimadzu Scientific Instruments Inc., Columbia, Maryland). The samples wereinjected into a capillary column (30 m\u00d7 0.25 mm; 0.25 \u00b5m film thickness; liquid phase: J&WDB 23) with helium as the carrier gas. The column temperature was initially set to 153 \u25e6Cfor 2 min, then increased to 174 \u25e6C for 2.3 \u25e6C\/min, and to a final temperature of 220 \u25e6C for2 \u25e6C\/min. The detector and injector temperatures were both set at 250 \u25e6C. The chromato-graphic peaks of the fatty acids were integrated and identified using the Shimadzu softwarepackage (version 7.2.1 SP1) and were then compared to known fatty acid standards (GLC463 and GLC 68B), as supplied by Nu-Chek Prep, Inc. (Elysian, MN, USA) and a sample ofwell-characterized Menhaden fish oil (PUFA-3 from Matreya, Inc., Pleasant Gap, PA, USA).The individual fatty acids were calculated and reported as weight percent of the totalidentified fatty acids using the peak area percentages and mass response factors relative toC18:0. The contents of the most nutritionally important fatty acids, EPA and DHA, wereadditionally analyzed using the internal standard C23:0 FAME.2.6. Lipid Oxidation AnalysisThe fish samples (30 g) were placed in sealed tubes under a normal air headspace andstored at refrigeration temperature for 30 days to record the generation of oxidation prod-ucts. The lipid peroxidation of the fish lipids was assessed using the FOX assay for primarylipid oxidation products, hydroperoxides [33], and malonaldehyde [34], a secondary lipidperoxidation product. To calibrate the lipid peroxides, a hydrogen peroxide solution wasused to oxidize ferrous to ferric ions and to generate a linear standard curve (0\u2013120 \u00b5M).One gram of ground fish was homogenized in 4 mL propanol and added to the FOXreagent (xylenol orange) along with ferrous ammonium sodium sulfate. Absorbance read-ings were taken at 560 nm using a Shimadzu UV spectrophotometer (Columbia, MD, USA)and converted to lipid peroxides using the equation:Lipid peroxides = Abs 560 nm \u00d7 133.5 \u2212 1.765 (2)where Lipid peroxides (\u00b5M); Abs 560 nm and slope of standard curve = 133.5.The MDA content of the fish was from 5 g filet tissue blended in a homogenizerwith distilled water containing trichloroacetic acid (7.5% w\/v), propyl gallate (0.1% w\/v,Sigma), and ethyenediaminetetracetic acid (0.1% w\/v). The filtrate was reacted with 2-TBA(0.02 M, Sigma) and heated in a boiling water bath for 40 min. Absorbance was recorded at532 nm using a Shimadzu UV spectrophotometer with a standard curve constructed usingMDA standard (1,1-3-3-tetrathoxypropane (TEP, Sigma). The malonaldehyde content ofthe samples was expressed in units of mg MDA\/100 g tissue.2.7. L. innocua Inhibition AssayThe fish extracts were obtained using a sequential hexane extraction (e.g., 1:5 w\/v;3\u00d7) followed by distilled water extraction in triplicate. The hexane extracts were filteredand evaporated under a vacuum at 45 \u25e6C. The water extracts were freeze-dried. The driedextracts were weighed to determine their yield. All of the extracts were frozen (\u221220 \u25e6C)until used.We used Listeria innocua (FSL C2-008) to model microbial growth. The bacterial strainwas isolated from a fish processing plant, and the stock was kept frozen at \u221280 \u25e6C beforeuse. The inoculum was thawed and streaked onto Brain\u2013Heart Infusion (BHI) agar using asterile disposable loop before incubation at 37 \u25e6C for 24 \u00b1 1 h. A colony of L. innocua wasidentified from the overnight culture, recovered, and washed three times in PBS (Difco)and centrifuged (1500 RPM for 5 min, 20 \u25e6C). The pellets were re-suspended in PBS tocontain initial bacteria concentrations of 109 cfu\/mL. Serial dilutions were made in PBS toachieve a starting concentration of approximately ca 106 cfu\/mL. Fresh cultures preparedin 5 mL of BHI broth were prepared for each experiment and the incubation period wasstandardized for 18 h at 37 \u25e6C.Foods 2023, 12, 111 5 of 14To generate the Listeria innocua growth curves, 5 mg of the hexane or water ex-tract collected from different fish samples (e.g., commercial smoked, FN non-smoked,FN half-smoked, FN fully smoked) were dissolved in dimethyl sulfoxide (DMSO, Ther-mos ScientificTM, Waltham, MA, USA) and BHI broth. Aliquots (100 \u00b5L) of the dilutedstock culture were added to each of the extraction samples to achieve an initial bacterialconcentration of ca 105 cfu\/mL. The control tubes were devoid of fish extracts. An initialaliquot was withdrawn immediately to establish a time zero reading, with the remainingtransferred to a shaking incubator set to 37 \u25e6C. Subsequent aliquots were withdrawn at2 h intervals over the total 8 h test period. Appropriate dilutions were made in PBS beforesurface plating. The experiments were conducted in triplicate, with three rounds of sam-pling. For the first round, three dilutions for each treatment at each time point were plated;while for the second and third rounds, two dilutions were performed in order to yieldcountable numbers. The BHI plates were incubated at 37 \u25e6C for 24 h. The experiment wasconducted three times in total to establish L. innocua growth curves. A new single colonywas selected every time to prepare the overnight culture. The lag times used to define therelative inhibitory effects of the different fish extracts on L. Innocua were determined usingthe Gompertz equation [35].2.8. Statistical AnalysisAll of the results are presented as means\u00b1 Standard Deviation (SD). Statistical analysiswas conducted using One-Way or Two-Way Analysis of Variance with Tukey\u2019s post hoctests (MINITAB software (Version 14, Minitab Inc., State College, PA, USA) with p < 0.05representing a statistically significant difference.3. ResultsThe moisture content of FN non-smoked salmon (72.4 \u00b1 1.79%) was higher (p < 0.05)than FN half-smoked (65.5 \u00b1 3.01%) and markedly higher (p < 0.001) than the FN fullysmoked (10.7 \u00b1 0.8%). Comparatively, the moisture content of commercial smoked fish(67.0 \u00b1 4.2%) resembled that of the FN half-smoked product. The corresponding sodiumand potassium concentrations expressed in the dry weight of the fish were considerablyhigher both in the FN half-smoked (Na-13.5 \u00b1 3 ppm; K-16.1 \u00b1 2 ppm) (p < 0.05) andFN fully smoked (Na- 81 \u00b1 9 ppm; K-103 \u00b1 11 ppm) fish compared to the non-smokedcontrol (Na-0.9 \u00b1 0.1 ppm; K-5.9 \u00b1 0.8 ppm). We attribute these differences to both thepractice of applying salt to fish prior to smoking as a pre-curing process as well as thedegree of dehydration that resulted from the duration of the smoke processing. The totalfat content (g\/100 g) of FN non-smoked salmon (17.86 \u00b1 1.67) was greater (p < 0.05) thanboth FN half-smoked (12.95 \u00b1 1.14) and FN fully smoked (12.24 \u00b1 1.3). For the sake ofcomparison, the fat content recovered from the commercial smoked salmon reference waslower (11 \u00b1 2.0).The PAH profile of the FN smoke-processed fish is expressed on a dry weight basisand is presented in Table 1. There were no detectable PAHs recovered from the non-smokedFN or commercial smoked fish controls. In the FN smoked fish, however, a number oflow-molecular-weight PAHs were identified and quantified in both the half-smoked andfully smoked fish samples. The concentration of PAHs recovered from the FN half-smokedproducts was only 2.5% of the total PAHs recovered from the fully smoked fish samples(p < 0.01). Of the 13 different PAHs, the concentrations of low-molecular-weight PAHs(e.g., 2\u20134 aromatic rings, including naphthalene, acenaphthylene, acenaphthene, fluo-rene, phenanthrene, anthracene, fluoranthene and pyrene) were present in only smallconcentrations compared to the fully smoked fish. Phenanthrene was the most dom-inant low-molecular-weight PAH in both FN half- and fully smoked fish samples. Inaddition, the fully smoked fish also contained a few high-molecular-weight PAHs (e.g.,5\u20136 aromatic rings), namely benzo(a)anthracene, (B(k)P) and chrysene. Other high-molecular-weight PAHs, for example, benzo(b)fluoranthene (B(b)F), benzo(k)fluoranthene, (B(f)F andbenzo(a)pyrene (B(a)P were not detected in FN half-smoked or fully smoked fish, respec-Foods 2023, 12, 111 6 of 14tively. The yield of \u2211 (BaP eqi), a product of the concentration of individual PAH and thetoxic equivalent factor, was approximately 350 times greater in the FN smoked samples,which reflected the difference in total PAH recovered between FN half-smoked and FNfully smoked fish.Table 1. Polycyclic aromatic hydrocarbon (PAH) content recovered from non-smoked FN andcommercial salmon and half-smoked and fully smoked FN salmon 1.PAH Non-Smoked 2 FN Half-Smoked FN Fully SmokedNaphthalene ND 3 229 \u00b1 76 a 351 \u00b1 87 bAcenaphthylene ND 351 \u00b1 92 a 586 \u00b1 210 bAcenaphthene ND 31 \u00b1 15 a 117 \u00b1 18 bFluorene ND 122 \u00b1 46 a 532 \u00b1 85 bPhenanthrene ND 382 \u00b1 137 a 3191 \u00b1 373 bAnthracene ND 76 \u00b1 15 a 538 \u00b1 65 bFluoranthene ND 46 \u00b1 15 a 308 \u00b1 46 bPyrene ND 31 \u00b1 15 a 273 \u00b1 37 bBenzo[\u03b1]anthracene ND ND 13 \u00b1 4 bChrysene ND ND 27 \u00b1 12 bBenzo[b]fluoranthene ND ND NDBenzo[k]fluoranthene ND ND NDBenzo[\u03b1]pyrene ND ND NDTotal PAH ND 1145 \u00b1 382 a 5972 \u00b1 544 bTotal BAP eqi. 4 ND 0.0109 3.971 Values represent a dry weight (\u00b5g\/kg) and are expressed as Mean \u00b1 standard deviation. Means with differentletters are significantly different (p < 0.05). 2 Refers to both commercial and First Nation (FN) non-smoked samples,respectively. 3 ND = not detected (e.g., below the detection limit of 0.001 ug\/g). No PAHs were detected in thecommercial cold smoked fish samples. 4 \u2211 (BaP eqi) = Toxic equivalent factors for total BA.The individual fatty acid concentrations present in the FN smoked and non-smokedfish are presented in Supplement Table S2. A summary of the nutritionally importantfatty acid groups is shown in Table 2. In general, all fatty acids, regardless of the degreeof saturation, were lower (p < 0.05) in fish after undergoing the thermal half-smokedand fully smoked processes, respectively. Of interest was the observation that very littledifference occurred in the individual fatty acids between the fish that were half-smokedor fully smoked. A notable reduction in fatty acids was also observed in the heat-treatedcommercial smoked fish, which for the purpose of this study was used only as a referencepoint, as the starting fish source was different from that used by FN; notwithstanding aswell the smoking procedure, which was also very different. Fatty acids were likely lostquickly during the initial heat process used with smoking, a response of fat liquefying atthe high temperatures used and the quality of the fat characteristic of salmon. The relativeloss of polyunsaturated fatty acids was greater (p < 0.05) compared to saturated fatty acids,which we attribute again to the lower melting point of unsaturated fatty acids. For example,the relative losses in omega-3 (range- 41\u201345%) and omega-6, (range- 42\u201344%) were highestafter smoking compared to saturated fatty acids (range- 27\u201334%). A summary of thechanges in the important fatty acid subclasses attributed to smoking is presented in Table 2.The omega-6 PUFA content in thr fish was present in relatively lower concentrationscompared to omega-3 fatty acids; however, both fatty acid groups lost approximately50 percent during the specific smoke processing. The omega-3\/omega-6 ratio also appearedto be higher, but this again was not significant and, in general, reflected the proportionallysimilar loss of lipids for all treatments.Foods 2023, 12, 111 7 of 14Table 2. Summary of nutritionally important fatty acid contents of FN non-smoked, half-smoked,fully smoked and commercial salmon 1.Fatty Acid Non-Smoked Half-Smoked Fully Smoked CommercialSFA 3.56 \u00b1 0.33 a 2.33 \u00b1 0.29 b 2.58 \u00b1 1.08 b 1.89 \u00b1 0.67PUFA 5.18 \u00b1 0.41 a 2.88 \u00b1 0.31 b 2.89 \u00b1 0.33 b 0.06 \u00b1 0.03cis-MUFA 8.19 \u00b1 0.80 a 6.47 \u00b1 0.77 b 6.74 \u00b1 4.29 b 2.54 \u00b1 0.40C18:2 n-6 0.45 \u00b1 0.09 a 0.21 \u00b1 0.02 b 0.24 \u00b1 0.18 b 0.11 \u00b1 0.00C20:4 n-6 0.21 \u00b1 0.06 a 0.05 \u00b1 0.00 b 0.06 \u00b1 0.04 b 0.06 \u00b1 0.02C20:5 n-3 1.20 \u00b1 0.09 a 0.72 \u00b1 0.07 b 0.78 \u00b1 0.60 b 0.73 \u00b1 0.09C22:6 n-3 2.20 \u00b1 0.17 a 1.30 \u00b1 0.12 b 1.20 \u00b1 0.70 b 1.70 \u00b1 0.25Omega-3 4.50 \u00b1 0.36 a 2.50 \u00b1 0.23 b 2.60 \u00b1 0.80 b 2.80 \u00b1 0.34Omega-6 0.77 \u00b1 0.17 a 0.33 \u00b1 0.04 b 0.38 \u00b1 0.28 b 0.28 \u00b1 0.03Omega-3\/6 5.80 7.58 6.86 9.891 Values given are means \u00b1 standard deviations (n = 6). Expressed as g\/100 g. Means with different superscriptletters (a,b) in rows are significantly different (p < 0.05). Statistical analysis did not include Commercial salmon asthey are not from the same source as FN salmon. See Supplement Table S2 for the complete fatty acid profiles.The application of traditional FN smoke preservation to the fish resulted in lipidoxidation (p < 0.05), which was monitored over a 30-day period (Figure 1). This observationwas particularly striking in the processed fish that received the full-smoke protocol. Thetemporal patterns of lipid hydroperoxide generation at refrigeration temperature were fairlyconstant in all of the processing treatments, with the exception of the FN fully smoked fish;characterized as having a lag phase of approximately 8 days before propagation occurred(Figure 1A). For comparison purposes, the same trend was also observed for commercialsalmon that had not been smoked.Foods 2022, 11, x FOR PEER REVIEW 8 of 15     (A) (B) Figure 1. (A) Lipid hydroperoxide content in commercial and FN non-smoked and FN half-smoked and fully smoked FN salmon versus storage time (days); (B) Malonaldehyde (MDA) content in com-mercial and FN non-smoked salmon and FN half-smoked and fully smoked FN salmon during stor-age time (days). Values represent mean \u00b1 SD (n = 3). Superscripts with different alphabets (a\u2013c) are significantly different (p < 0.05). In the non-smoked fish, the primary products of lipid oxidation appeared rapidly up to day 21, reaching levels that were higher p < 0.05) than the values observed in the half-smoked fish. The onset of hydroperoxides production in the FN fully smoked fish re-mained very low and significantly lower than that obtained in the FN half-smoked fish (p < 0.05). A similar trend was observed for the secondary products of lipid oxidation, namely malonaldehyde monitored at storage days of 9, 21, and 30, respectively (Figure 1B).  The growth curves of Listeria innocua over 8 h obtained in the presence of water and hexane extracts of non-smoked and FN smoked fish are shown in Figure 2. Listeria innocua growth was not mitigated by exposure to the water extract (Figure 2A) but did show sig-nificant (p < 0.05) inhibition to the hexane extracts (Figure 2B) collected from only FN fully smoked salmon samples. The time defining a lag phase for L. innocua growth was approx-imately 3 h, 4 h, and >8 h, respectively, for commercial smoked, half-smoked, and fully smoked hexane extracts. This corresponded to 19.4 \u00b1 3.55 and 23.4 \u00b1 2.20 percent of growth inhibition for the hexane extracts derived from the commercial smoked and FN half-smoked salmon, respectively. For interest, the hexane extracts collected from the fully smoked salmon samples produced the highest suppression (34.2 \u00b1 0.5%), which was at-tributed to the prolonged lag phase.      c c    cb  b b   aa02040600 2 4 7 9 14 21 30Lipid peroxides Concentration (\u03bcM) Time (day)Commercial SalmonNon-Smoked SalmonPartially-Smoked SalmonFully-Smoked Salmoncc ccccb bba aa048129 21 30mg MDA\/100g fish muscleTime (day)Commercial SalmonNon-Smoked SalmonPartially-Smoked SalmonFully-Smoked SalmonFigure 1. (A) Lipid hydroperoxide content in commercial and FN non-smoked and FN half-smokedand fully smoked FN salmon versus storage time (days); (B) Malonaldehyde (MDA) content incommercial and FN non-smoked salmon and FN half-smoked and fully smoked FN salmon duringstorage time (days). Values represent mean \u00b1 SD (n = 3). Superscripts with different alphabets (a\u2013c)are significantly different (p < 0.05).Foods 2023, 12, 111 8 of 14In the non-smoked fish, the primary products of lipid oxidation appeared rapidlyup to day 21, reaching levels that were higher p < 0.05) than the values observed in thehalf-smoked fish. The onset of hydroperoxides production in the FN fully smoked fishremained very low and significantly lower than that obtained in the FN half-smoked fish(p < 0.05). A similar trend was observed for the secondary products of lipid oxidation,namely malonaldehyde monitored at storage days of 9, 21, and 30, respectively (Figure 1B).The growth curves of Listeria innocua over 8 h obtained in the presence of water andhexane extracts of non-smoked and FN smoked fish are shown in Figure 2. Listeria innocuagrowth was not mitigated by exposure to the water extract (Figure 2A) but did showsignificant (p < 0.05) inhibition to the hexane extracts (Figure 2B) collected from only FNfully smoked salmon samples. The time defining a lag phase for L. innocua growth wasapproximately 3 h, 4 h, and >8 h, respectively, for commercial smoked, half-smoked, andfully smoked hexane extracts. This corresponded to 19.4 \u00b1 3.55 and 23.4 \u00b1 2.20 percentof growth inhibition for the hexane extracts derived from the commercial smoked andFN half-smoked salmon, respectively. For interest, the hexane extracts collected from thefully smoked salmon samples produced the highest suppression (34.2 \u00b1 0.5%), which wasattributed to the prolonged lag phase.Foods 2022, 11, x FOR PEER REVIEW 9 of 15     (A) (B) Figure 2. Effect of smoked salmon water (A) and hexane (B) extracts against Listeria innocua. Values represent means of 3 triplicates, but the SD is too small to show. 4. Discussion All of the smoked salmon samples gifted to us by Canada\u2019s First Nation communities of Tl\u2019azt\u2019en and Lheidli T\u2019enneh were obtained from a traditional smokehouse that em-ployed procedures that did not control temperature and time. A commercial smoked salmon, which was obtained from a different source, was included in the analysis for the purpose of having a commercial reference. The smoking times for the FN half-smoked and FN fully smoked samples were typically 2\u20133 days and 5\u20136 days, respectively, which was identical to our previous study [2], but in comparison, much longer than that used by others [36,37]. The uncontrolled smoking temperature and the long smoking time used in their traditional method of smoke processing are two important factors related to gener-ating both the level and type of PAHs reported in this study.  Curing fish using cold or hot smoke methods ultimately reduces the moisture content and, most importantly, water activity. Thus, the lower moisture contents recorded in both of the FN smoked fish products relative to a commercial product and our FN non-smoked product were expected. This change corresponded to considerably higher salt contents, most notably measured in the FN fully smoked products. Processing fish at high temper-atures without controlling the distance from the heat source is common to the traditional FN smoke processing employed herein and is thus a critical factor in explaining the final moisture results of the smoke-processed fish. For smoking to be effective for drying, suf-ficient time is needed for the heat to penetrate the muscles of the fish, resulting in the release of bound water and the substitution of moisture with the concomitant uptake of volatile organics derived from the wood heat source. Once the internal temperature is reached, the drying process and the moisture content will be affected by the duration of smoking. This was observed in the present study with the FN fully smoked fish exposed for up to 2 to 3 days longer than the FN half-smoked product using the same traditional process. The dehydration process, therefore, can be described as having sufficient time for heat derived from the wood fire to penetrate into the muscles of the fish, reaching an in-ternal temperature that facilitates a high rate of moisture loss over time. The use of salt as 567890 2 4 6 8log cfu\/mLTime (h) Commercial SalmonNon-Smoked SalmonPartially-Smoked SalmonFully-Smoked Salmon567890 2 4 6 8log cfu\/mLTime (h)Commercial SalmonNon-Smoked SalmonPartially-Smoked SalmonFully-Smoked SalmonFigure 2. Effect of smoked salmon water (A) and hexane (B) extracts against Listeria innocua. Valuesrepresent means of 3 triplicates, but the SD is too small to show.4. Di cussionAll of the smoked salmon samples gifted to us by Canada\u2019s First Nation communi-ties of Tl\u2019azt\u2019en and Lheidli T\u2019enneh wer obtained from a traditi nal smokehouse thatemployed p ocedures that did not control temperature and time. A commercial smokedsalmon, which was obtained from a different source, was included in the analysis for theurp se of having a commercial fer nce. The smoking times for the FN half-smokedand FN fully smoked samples were typically 2\u20133 d ys and 5\u20136 days, respectively, whichwas identical to our previo s study [2], but in comparison, much longer than that usedby others [36,37]. The uncontrolled s oking temperature and the long smoking timeused in their traditional ethod of smoke processing are two important factors related togenerating both the level and type of PAHs reported in this study.Foods 2023, 12, 111 9 of 14Curing fish using cold or hot smoke methods ultimately reduces the moisture contentand, most importantly, water activity. Thus, the lower moisture contents recorded inboth of the FN smoked fish products relative to a commercial product and our FN non-smoked product were expected. This change corresponded to considerably higher saltcontents, most notably measured in the FN fully smoked products. Processing fish athigh temperatures without controlling the distance from the heat source is common to thetraditional FN smoke processing employed herein and is thus a critical factor in explainingthe final moisture results of the smoke-processed fish. For smoking to be effective fordrying, sufficient time is needed for the heat to penetrate the muscles of the fish, resultingin the release of bound water and the substitution of moisture with the concomitant uptakeof volatile organics derived from the wood heat source. Once the internal temperature isreached, the drying process and the moisture content will be affected by the duration ofsmoking. This was observed in the present study with the FN fully smoked fish exposedfor up to 2 to 3 days longer than the FN half-smoked product using the same traditionalprocess. The dehydration process, therefore, can be described as having sufficient timefor heat derived from the wood fire to penetrate into the muscles of the fish, reachingan internal temperature that facilitates a high rate of moisture loss over time. The use ofsalt as a pre-application step, along with the simultaneous uptake and retention of smokevolatiles [38], would produce low water activity and low-moisture final dried product,which in combination, preserves the quality (e.g., color, texture) [39]. The high salt content,despite having important preservation qualities, also presents potential health risks if thesmoked fish cured using this method is consumed regularly [16].The presence and concentrations of individual PAHs reported by others in smokedsalmon are highly variable due to differences in the smoking processes, in particular, thesmoke generation conditions that include the temperature reached for pyrolysis and thesmoking duration, the fats lost due to liquefaction during heat exposure, and the typeof wood used to smoke-process the food products [40]. In the present study, the PAHcontents of the smoked fish were only derived during the smoking process, as no PAHswere detected in the FN non-smoked fish or the commercial salmon samples, thus rulingout environmental contamination as a cause for PAH residues. The total PAH contentin our smoked fish was similar to the levels reported in an earlier study [2] and wassimilar to those by other investigators [13,41]. We confirmed the observation that greateramounts of total PAHs were recovered from the FN fully smoked salmon compared tothe FN half-smoked salmon, thus identifying the smoking time used in traditional FNpreservation methods as a primary factor influencing the total PAHs recovered from theFN smoked salmon. We used safety standards designed for PAHs relative to B(a)P (e.g.,Toxic equivalents of B(a)P)) to show that the PAHs present in the fully smoked salmonwere markedly greater than that present in the half-smoked salmon.An important finding was that low-molecular-weight PAHs predominated in FNsmoked salmon, which is similar to our previous results [2]. Of these particular PAHsrecovered, fluorene, phenathrene, napththalene, benzo[a}anthracene, and chrysene havea Group 2B classification as possible human carcinogens [42,43]. Naphthalene, the mostconcentrated PAH recovered in both the FN half-smoked and fully smoked fish posespotential health risks associated with chronic exposure that includes both cataracts andretinal hemorrhage, whereas headache, nausea, and anemia can occur with acute exposure(44). Occupational workers exposed to naphthalene have recorded laryngeal carcinomasor neoplasms in the pylorus and cecum [44]. Chrysene was only recovered from the FNfully smoked fish, which confirmed our earlier reports [2]. Human data on chrysenecarcinogenicity are unavailable; however, it has been reported to induce carcinomas andmalignant lymphoma in mice [45]. Chronic exposure to chrysene has also been associatedwith disorders that include immunologic deficiency syndromes and kidney, liver, and lungneoplasm [45].Foods 2023, 12, 111 10 of 14Unlike our previous study, higher molecular weight PAHs that included B(a)P werenot detected herein in both FN half-smoked and fully smoked fish, respectively. Thefact that we did not reproduce our previous finding in this respect is of interest andcould be related to the differences in the wood sources used between the studies. Forexample, available wood sources during our two studies included mixtures of spruceand alder. The relative amount of each wood source used in our former study was notrecorded; however, in the present study, we requested that spruce be preferentially used,which is a relatively soft wood and lower than many other kinds of wood. Others havereported a higher risk associated with carcinogenic and mutagenic toxicity equivalentsoccurred when hardwoods were used to smoke-cure fish for longer durations [13]. Leg-islation for the maximum levels of B(a)P for smoked meats and smoked meat productsset in 2006 is 5 \u00b5g\/kg, but there are many cases where B(a)P exceeded this. Japaneseworkers, for example, reported that smoked, dried fish products derived from bonitocontained high levels of B(a)P residue [46], which more recently was reduced by counter-measures using smoking on a hot plate with wood chips [47]. B(a)P, classified as a Group1 carcinogen, was chosen as a marker for potential carcinogenic risks of PAH exposurein food. More recent evidence from a number of in vivo bioassays using experimentalanimals have identified up to 15 PAHs (e.g., benz[a]anthracene, benzo[b]fluoranthene,benz[j]-fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, benzo[a]pyrene, chrysene,cyclopenta[cd]pyrene, dibenz[a,h]anthracene, dibenzo[a,e]pyrene, dibenzo[a,h]pyrene,dibenzo[a,i]pyrene, dibenzo[a,l]pyrene, indeno[1,2,3-cd]pyrene, and 5-methylchrysene)with potential adverse health risk effects from long-term dietary intake [48]. Of the 15 PAHsidentified above, only small amounts of chrysene and benz[a]anthracene were only detectedin the FN fully smoked products. Thus, addressing the potential carcinogenic potential ofexposure to the PAH mixtures identified in this study is muted by the fact that PAHs withchronic health concerns were either not present in FN smoked fish or only occurred in traceamounts in the fully smoked fish products. Nevertheless, future studies addressing howto optimize the smoke-processing to eliminate all PAHs are warranted. This goal wouldfollow the Codex Alimenarius Commission, the code of practice, which called for reducingthe PAH contamination of food processed using smoke curing [49].The application of traditional FN smoke processing methods for fish resulted in signif-icant losses in all classes of free fatty acids compared to non-smoked control (SupplementTable S2 and Table 2). This observation corresponded to the proportional loss of approxi-mately 27% total fat in FN smoked fish relative to the non-smoked control. Others havealso reported losses in total fish PUFA following smoke processing [50]. Despite the pro-portional losses in MUFA, PUFA, and SFA, respectively, the FN smoke processing protocoldid not affect the high omega-3 fatty acids\/omega 6 ratio that typically exists in salmonand reflects their cold-water habitat. In wild Atlantic salmon, an n-3 to n-6 PUFA ratio of 11was compared to a ratio of 3.6 in farmed Atlantic Salmon [51]. Using the salmon source inthis study, our respective n-3 to n-6 PUFA ratios ranged from approximately 6 to 7, with noappreciable change attributed to the different FN smoking procedures. Although there wasa 50 percent loss in both EPA and DHA due to the smoke processing, these fish were stillsources of HUFA-n-3, which suggests that increasing daily fish intakes could accomplishreaching daily recommendations of total EPA + DHA, proposed for health benefits [52].Parallel to these findings was the fact that a 20\u201330-day cold-storage trial for fishproduced characteristic patterns of shelf-life, depicted by a relative tendency to generatelipid hydroperoxide (primary) and malonaldehyde (secondary) lipid oxidation productsin the non-smoked fish. It is expected that the proportionally greater n-3 PUFA content infish tissues enhances the relatively greater susceptibility for lipid peroxidation [53], withMDA representing the principal secondary peroxidation product of n-3 PUFAs, comparedto n-6 PUFA [54]. Moreover, exposing fish to heat during smoke processing results intriglyceride and phospholipids hydrolysis and the subsequent yield of free fatty acidsthat are available for autooxidation during subsequent storage, if not lost during smoking.Related to the stability of PUFAs in smoke-processed fish was the observed slower rateFoods 2023, 12, 111 11 of 14of lipid peroxidation when fish received the FN smoke procedures. Normally, smoked,refrigerated fish products are shelf stable with a shelf life of 21 to 35 days, depending on thecategory of smoking applied [55]. In this study, the products of primary oxidation, namelyhydroperoxides, occurred rapidly in non-treated salmon but were reduced in the FN half-smoked and especially markedly lower in the FN fully smoked salmon samples. Secondaryby-products of lipid oxidation, including some off-flavor compounds and malonalde-hyde, are generated from hydroperoxides, and typically, malonaldehyde levels that exceed2 mg MDA\/kg are regarded as producing objectionable odor and color. FN smoked fishthat were stored at refrigeration temperature over prolonged periods reaching 30 dayshad an MDA content that was well below this threshold concentration. Hence, an anti-peroxidation effect of the FN smoke processing method was evident and can be explainedby both the brine that was applied prior to smoke processing and the generation of phenoliccompounds that occurred during smoking that impregnate the fish flesh and contributeto antioxidant activity [56]. Moreover, it is also likely that the peroxide content presentin the fully smoked salmon samples was relatively stable, thus reducing the subsequentgeneration of secondary lipid oxidation products [33].The sequential extraction of the smoked fish samples, first with water and followed byhexane, allowed us to demonstrate that hydrophobic compounds recovered in extracts fromthe FN smoked fish were responsible for the antimicrobial effect against L. innocua. Ourformer study also reported a similar antimicrobial property of hexane extracts from smoke-processed fish that corresponded to inhibiting growth of Staphylococcus aureus [17]. Woodphenolic compounds derived from multiple species have antimicrobial properties [57], andthis has also been reported with wood smoke tested against both spoilage and pathogenicmicroorganisms [58]. The reasons for choosing Listeria as a test organism in this studywere based on reports that smoked salmon is regarded as a risk factor for human listeriosissince smoked salmon can sporadically be re-contaminated with Listeria if systemic hygienicmeasures are not in place [16]. This occurs when Listeria, although damaged duringexposure to optimal time and temperature combinations of smoke processing, proceeds torecover during extended storage [15].5. ConclusionsIn this study, we further explored the risks and potential benefits of traditional FNsmoke-processing procedures for salmon preservation currently in use by two communitiesin northern B.C., Canada. According to the findings, the highest total B(a)P equivalentwas ascribed to the duration of the smoke curing process in the smokehouse and involvedmainly low-molecular-weight (LMW) PAHs. In accordance with these findings, B(a)P orother notable high-molecular-weight (HMW) PAHs with carcinogenic potential were notdetected at levels of concern in both smoked products. Despite the fact that the smokeprocessing of salmon resulted in a significant loss of lipids, this effect was quantitativelysimilar for all fatty acid groups and, more importantly, did not adversely affect the ratio ofessential n-3\/n-6 PUFA. Losses of PUFA are expected with the fat type of salmon and thedistance from the cooking flame during smoking. It was also important to observe that thegeneration of both primary and secondary lipid oxidation products was mitigated duringthe subsequent storage of the smoked fish. Furthermore, an apparent antimicrobial effectof FN smoke-processing, specific to the lipophilic constituents recovered from the smokedfish products, occurred with Listeria sp. Thus, the retention of lipid quality of smokedsalmon during storage and prevention of recontamination by Listeria organisms duringstorage would be regarded as benefits of the smoke processing conditions used by FN.On the whole, FN fully smoked processing of salmon may pose a potential risk to humanhealth since it generated the highest number of PAHs, which could, both individually orsynergistically, induce non-cancer or cancer processes. However, the extent of retention ofn-3\/n-6 essential acids and mitigation of lipid oxidation in a stored product, not to mentionthe prevention of Listeria sp., are benefits to consider in establishing a risk assessment ofFN smoke processing of fish.Foods 2023, 12, 111 12 of 14Supplementary Materials: The following supporting information can be downloaded at: https:\/\/www.mdpi.com\/article\/10.3390\/foods12010111\/s1, Table S1: Toxicity parameters for polycyclicaromatic hydrocarbons (PAHs) used to calculate the Toxic equivalent factors for total Benzo[a]pyrene(BaP); Table S2: Complete fatty acid composition analysis of non-smoked and smoked salmon.Author Contributions: Conceptualization, D.D.K., A.P.-S., X.C. and S.W.; writing\u2014original draftpreparation, D.D.K.; resources, D.D.K., A.P.-S. and S.W.; methodology, data analysis and curation,D.D.K., A.P.-S., A.S. and S.W.; writing\u2014review and editing, all. All authors have read and agreed tothe published version of the manuscript.Funding: This research was funded by Natural Sciences and Engineering Council (NSERC) grants toD.D.K (RGPIN-2019-04885), A.P.-S. (RGPIN-2018-04735) and S.W. (RGPIN-2015-04871).Data Availability Statement: Data are contained within the article or in Supplementary Materials.Acknowledgments: The authors are grateful for the donation of smoked fish samples from B.C. FirstNation communities of Tl\u2019azt\u2019en and Lheidli T\u2019enneh and Paul Broda for his assistance. We especiallythank Ellen Hao for her assistance with data collection and analysis. The Listeria innocua strain usedin this study was provided by Martin Wiedmann at Cornell University, USA.Conflicts of Interest: The authors declare that they have no competing conflict of interest.References1. Forsberg, N.D.; Stone, D.; Harding, A.; Harper, B.; Harris, S.; Matzke, M.M.; Cardenas, A.; Waters, K.M.; Anderson, K.A. 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Smailagic\u00b4, A.; Ristivojevic\u00b4, P.; Dimkic\u00b4, I.; Pavlovic\u00b4, T.; Dabic\u00b4 Zagorac, D.; Veljovic\u00b4, S.; Fotiric\u00b4 Ak\u0161ic\u00b4, M.; Meland, M.; Natic\u00b4, M.Radical scavenging and antimicrobial properties of polyphenol rich waste wood extracts. Foods 2020, 9, 319. [CrossRef]58. Su\u00f1en, E. Minimum inhibitory concentration of smoke wood extracts against spoilage and pathogenic micro-organisms associatedwith foods. Lett. Appl. Microbiol. 1998, 27, 45\u201348. [CrossRef]Disclaimer\/Publisher\u2019s Note: The statements, opinions and data contained in all publications are solely those of the individualauthor(s) and contributor(s) and not of MDPI and\/or the editor(s). MDPI and\/or the editor(s) disclaim responsibility for any injury topeople or property resulting from any ideas, methods, instructions or products referred to in the content.","@language":"en"}],"Genre":[{"@value":"Article","@language":"en"}],"IsShownAt":[{"@value":"10.14288\/1.0435932","@language":"en"}],"Language":[{"@value":"eng","@language":"en"}],"PeerReviewStatus":[{"@value":"Reviewed","@language":"en"}],"Provider":[{"@value":"Vancouver : University of British Columbia Library","@language":"en"}],"Publisher":[{"@value":"Multidisciplinary Digital Publishing Institute","@language":"en"}],"PublisherDOI":[{"@value":"10.3390\/foods12010111","@language":"en"}],"Rights":[{"@value":"CC BY 4.0","@language":"en"}],"RightsURI":[{"@value":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","@language":"en"}],"ScholarlyLevel":[{"@value":"Faculty","@language":"en"},{"@value":"Researcher","@language":"en"}],"Subject":[{"@value":"First Nation\u2019s smoke processing","@language":"en"},{"@value":"safety","@language":"en"},{"@value":"nutritional quality","@language":"en"},{"@value":"fish","@language":"en"},{"@value":"lipid oxidation","@language":"en"}],"Title":[{"@value":"A Risk\u2013Benefit Analysis of First Nation\u2019s Traditional Smoked Fish Processing","@language":"en"}],"Type":[{"@value":"Text","@language":"en"}],"URI":[{"@value":"http:\/\/hdl.handle.net\/2429\/85969","@language":"en"}],"SortDate":[{"@value":"2022-12-26 AD","@language":"en"}],"@id":"doi:10.14288\/1.0435932"}