Smoked Salmon Research Articles

Fatty Acid Composition of Commercial Smoked Salmon Products

In this study, the fatty acid composition of smoked salmon fillets sold in grocery stores in Türkiye was investigated. Gas chromatography (GC) was used to determine fatty acid composition from extracted lipid. The main saturated fatty acids observed in smoked salmon samples were myristic acid (C14:0), palmitic acid (C16:0) and stearic acid (C18:0); monounsaturated fatty acids were palmitoleic acid (C16:1), oleic acid (C18:1n9), and vaccenic acid (C18:1n7); polyunsaturated fatty acids (PUFA) were linoleic acid (C18:2n6), eicosapentaenoic acid (EPA, C20:5n3) and decosahexaenoic acid (DHA, C22:6n3). Among the monounsaturated fatty acids, oleic acid was found to be the fatty acid with the highest value. Oleic acid amounts were found to vary between 27.22% and 35.52%. PUFA values in smoked salmon fillet groups were determined as 27.77%, 27.49%, 32.94% and 30.62%. The highest EPA value was determined in F1 group with 4.29% and the lowest value was determined in F2 group with 2.07%. DHA amounts were between 11.74% and 6.22%. The ratio of Σn6/Σn3 was between 0.80 (F4 group) and 1.16 (F2 group). As a result, it was concluded that the smoked fish fillets examined had high nutritional quality in terms of fatty acids. Among the groups, especially F3 and F4 groups were found to have rich content in terms of PUFA and Σn3 values.

Plasmid-Associated Bacteriocin Produced by Pediococcus pentosaceus Isolated from Smoked Salmon: Partial Characterization and Some Aspects of his Mode of Action.

Strain ST3Ha, isolated from commercially available smoked salmon, was identified as Pediococcus pentosaceus based on biochemical and physiological tests and 16S rRNA sequencing. Strain ST3Ha produces a class IIa bacteriocin active against lactic acid bacteria, Listeria monocytogenes and Enterococcus faecalis. The antimicrobial peptide was inactivated by proteolytic enzymes, confirming his proteinaceous nature, but was not affected when treated with α-amylase, SDS, Tween 20, Tween 80, urea, and EDTA. No change in activity was recorded after 2h at pH values between 2.0 and 9.0 and after treatment at 100°C for 120min or 121°C for 15min. The mode of action against Listeria ivanovii subsp. ivanovii ATCC 19119 and E. faecalis ATCC 19443 was bactericidal, resulting in cell lyses and enzyme leakage. The highest level of activity (1.6 × 106 AU/mL) was recorded when cells were grown at 37°C or 30°C in MRS broth (pH 6.5). Antimicrobial peptide ST3Ha adsorbs at high levels to the sensitive test organisms on strain-specific manner and depending on incubation temperature, environmental pH, and presence of supplemented chemicals. Based on PCR analysis, P. pentosaceus ST3Ha harbor a 1044-bp plasmid-associated fragment corresponding in size to that recorded for pediocin PA-1. Sequencing of the fragment revealed a gene identical to pedB, reported for pediocin PA-1. The combined application of the low levels (below MIC) of ciprofloxacin and bacteriocin ST3Ha results in the synergetic effect in the inhibition of L. ivanovii subsp. ivanovii ATCC 19119. Expressed by P. pentosaceus ST3Ha, bacteriocin was characterized as low cytotoxic, a characteristic relevant for its application in food industry and/or in human and veterinary medical practices.

Modeling the Growth of Six Listeria monocytogenes Strains in Smoked Salmon Pâté

In this study, the growth of six L. monocytogenes strains isolated from different fish products was quantified and modeled in smoked salmon pâté at a temperature ranging from 2 to 20 °C. The experimental data obtained for each strain was fitted to the primary growth model of Baranyi and Roberts to estimate the following kinetic parameters: lag phase (λ), maximum specific growth rate (μmax), and maximum cell density (Nmax). Then, the effect of storage temperature on the obtained μmax values was modeled by the Ratkowsky secondary model. In general, the six L. monocytogenes strains showed rapid growth in salmon pâté at all storage temperatures, with a relatively short lag phase λ, even at 2 °C. The growth behavior among the tested strains was similar at the same storage temperature, although significant differences were found for the parameters λ and μmax. Besides, the growth variations among the strains did not follow a regular pattern. The estimated secondary model parameter Tmin ranged from -4.25 to -3.19 °C. This study provides accurate predictive models for the growth of L. monocytogenes in fish pâtés that can be used in shelf life and microbial risk assessment studies. In addition, the models generated in this work can be implemented in predictive modeling tools and repositories that can be reliably and easily used by the fish industry and end-users to establish measures aimed at controlling the growth of L. monocytogenes in fish-based pâtés.

The Role of Eco-Labels in Making Environmentally Friendly Choices: An Eye-Tracking Study on Aquaculture Products with Italian Consumers

Eco-labels are crucial in helping consumers make sustainable food choices. However, previous literature has shown that eco-labels lack visibility and, frequently, are not easy for consumers to see. The main goal of the present study was to analyse the influence of aquaculture eco-labels’ visual elements—size and saliency—on consumers’ visual attention and choice. The study uses an eye-tracking methodology, together with a choice experiment and a semiotic analysis. A word association (WA) task was used to explore how each eco-label’s graphic design influenced consumers’ perceptions. Sixty-one consumers’ eye movements were tracked while choosing smoked salmon and seabass products carrying different eco-labels. The results showed that size and saliency largely influence visual attention. The choice of aquaculture products was influenced only by the size of the eco-labels. According to the WA task, the shape, the symbols and the language in which the claim was written influenced consumers’ preferences. The findings contribute to marketing and food research, suggesting which visual elements should be considered to increase consumers’ interest in eco-labels.

The role of production method information on sensory perception of smoked salmon—A mixed-method study from Denmark

Product information is capable of steering the consumers’ expectation formation process. Therefore, this paper aims to investigate whether information on production method influence consumers’ preference and liking of smoked salmon. A consumer test was conducted among 92 consumers to determine liking of the smoked salmon on a 7-point hedonic scale before (blind) and after (informed) receiving information about production method (organic, conventional and wild-caught). Further, two explanatory focus group discussions (n = 5 in each group) were conducted to determine consumers’ belief on production method.A linear mixed-effects model analysis indicated that the consumer overall liking of wild-caught smoked salmon significantly increased after production method information was provided, while regarding organic and conventional smoked salmon no significant difference was noted. Post hoc test indicated that organic smoked salmon was significantly more liked than wild-caught smoked salmon (mean difference ± standard error: 0.652 ± 0.19, p < 0.01) in blind condition, however, between organic and conventional smoked salmon no significant difference was noted (-0.032 ± 0.19, p = 0.983). Further, in informed condition, organic smoked salmon was significantly more liked than conventional smoked salmon (0.50 ± 0.19, p < 0.05), however, between organic and wild-caught smoked salmon no significant difference was noted (0.228 ± 0.19, p = 0.452). Relative importance analysis results suggest that liking of taste was the most important contributor (26.84%) to smoked salmon overall liking (p < 0.05, R2 = 74.17%). Focus group discussion revealed that consumer beliefs related to food safety, animal welfare and sustainability as well as purchasing habits seem to influence smoked salmon preferences.Thus, organic aquaculture sector should focus on promoting consumer beliefs by providing reliable information based on scientific evidences that helps differentiates their products with that of conventional and wild-caught smoked salmon. Future studies might investigate other fish species to better understand the role of product method information on consumer preference and liking of fish.

Quantitative Risk Assessment of &lt;i&gt;Listeria monocytogenes&lt;/i&gt; in Smoked and Raw Salmon

Quantitative Risk Assessment of &lt;i&gt;Listeria monocytogenes&lt;/i&gt; in Smoked and Raw Salmon

Antimicrobial activity of 405nm light-emitting diode (LED) in the presence of riboflavin against Listeria monocytogenes on the surface of smoked salmon.

This study investigated the antimicrobial activity of 405nm light-emitting diode (LED) with and without riboflavin against Listeria monocytogenes in phosphate buffered saline (PBS) and on smoked salmon at different storage temperatures and evaluated its impact on food quality. The results show that riboflavin-mediated LED illumination in PBS 25°C significantly inactivated L. monocytogenes cells by 6.2 log CFU/mL at 19.2J/cm2, while illumination alone reduced 1.9 log CFU/mL of L. monocytogenes populations at 57.6J/cm2. L. monocytogenes populations on illuminated smoked salmon decreased by 1.0-2.2 log CFU/cm2 at 1.27-2.76kJ/cm2 at 4, 12, and 25°C, regardless of the presence of riboflavin. Although illumination with and without riboflavin caused the lipid peroxidation and color change in smoked salmon, this study demonstrates the potential of a 405nm LED to preserve the smoked salmon products, reducing the risk of listeriosis.

Antibacterial mechanism of riboflavin-mediated 460 nm light emitting diode illumination against Listeria monocytogenes in phosphate-buffered saline and on smoked salmon

The aim of this study was to elucidate the antibacterial mechanism of riboflavin-mediated 460 nm light emitting diode (LED) illumination against Listeria monocytogenes in phosphate buffered saline (PBS) solution and on the surface of smoked salmon by determining reactive oxygen species (ROS) production, bacterial membrane permeability, and DNA damage in PBS as well as bacterial metabolic inhibition on smoked salmon. Its antibacterial efficacy against L. monocytogenes in PBS and on the surface of smoke salmon was also evaluated. The results showed that LED illumination alone reduced 0.6 log CFU/ml of L. monocytogenes at dose of 0.2 kJ/cm2, while illumination with riboflavin (100 μM) inactivated 5.6 log CFU/ml in PBS at 20 °C. On the surface of smoked salmon, LED illumination with/without riboflavin reduced less than 1.0 log CFU/cm2 of L. monocytogenes populations at 4 °C at 12.8 kJ/cm2. At 10 °C, bacterial populations on non-illuminated and illuminated samples increased to 5.9 and 4.4 log CFU/cm2, respectively, whereas riboflavin-mediated LED illumination inactivated 1.0 log CFU/cm2. The amount of ROS observed in illuminated cells with riboflavin was higher than those of non-illuminated and illuminated cells. LED illumination alone induced cellular damage to metabolism of RNA and protein, while riboflavin-mediated illumination caused additional metabolic inhibition to DNA. Therefore, these results suggest that the antibacterial mechanism of riboflavin-mediated 460 nm LED illumination might be due to membrane and DNA damages by ROS generated from photo-reaction of riboflavin as well as metabolic inhibition. This study could provide novel insight in the application of riboflavin-mediated 460 nm LED technology to preserve smoked salmon at refrigeration temperatures, minimizing the risk of listeriosis.

Absence of anisakis nematodes in smoked farmed Atlantic salmon (Salmo salar) products on sale in European countries.

The increase of global demand of aquaculture products as compensation for the lowering of fishery sustainability has shown a parallel awareness by the consumers on the importance of the safety and quality of fish products. Among these, salmon industry has reached a leading position demonstrating the negligible risk of presence of zoonotic helminths such as anisakis nematodes in farmed salmon. Despite the massive production of data in literature on parasitological surveys carried out on fresh salmon, no data are published on processed farmed salmon such as smoked products. In 2016, 270 slices of smoked farmed Atlantic salmon (Salmo salar) and 13 smoked slices from wild sockeye salmon (Oncorhynchus nerka) have been analyzed by visual inspection and UV-press method searching for the presence of anisakid nematodes. No parasites were detected in samples from farmed Atlantic salmon, while 10 out of 13 from wild salmon were positive for Anisakis simplex s.s. larvae. This first survey on the possible presence of anisakid nematodes in processed smoked salmon confirms that this risk in farmed Atlantic salmon products has to be considered negligible.

Distinguishing Between Fresh and Frozen-thawed Smoked Salmon: Histology to Detect Food Adulteration in High-Value Products

The issue of food safety has acquired increased importance, and fraud is a major concern for the food industry. Among different types of food adulteration, there is the sale of frozen-thawed smoked salmon product as fresh, which not only decreases the quality of products but also misleads consumers and may involve associated health risks. In response to this problem, we tested the performance of histology to identify smoked salmon as fresh or frozen-thawed as a valid analytical method, so food business operators and official controllers can reliably and correctly classify the storage state of the product. Three groups of samples were prepared: group A (n = 36), fresh samples; group B (n = 36), frozen at -18°C for 30 days; and group C (n = 36), stored at -3°C for 30 days after packaging. Two histopathologists examined all samples in blind evaluations and classified them as fresh or frozen-thawed. Sensitivity, specificity, and interrater agreement were calculated. Results show high performance with the test: 80.6% sensitivity (95% confidence intervals [CI]: 64 to 91.8%); 95.6% specificity (95% CI: 89.1 to 98.8%); and Cohen's kappa was 0.81 (95% CI: 0.64 to 0.98%). Histology is a reliable and highly accurate method to differentiate fresh from frozen-thawed smoked salmon and could be used by the industry and official controllers to verify the labeling of the commercial product.

Gevo announces breakthrough development of low carbon no particulate renewable diesel

The aim of the study was the selection of appropriate enzymatic TTIs for quality and shelf life monitoring of ready-to-eat smoked fish products during refrigerated storage. The response of different types of enzymatic TTIs was kinetically modelled and correlated with the quality decay and shelf life of vacuum packed hot smoked eel and trout and cold smoked salmon fillets in the cold chain. The kinetics of shelf life determining quality indices for the tested smoked fish products were established via isothermal experiments. Mathematical models which describe the effect of the enzyme concentration, storage time and temperature on the response of the TTI were developed and validated at variable conditions. The effect of the temperature on the response change of the TTIs was expressed through activation energy and the values were calculated in the range of 80-150 kJ·mol−1. Applying the developed models, the required TTI design to reliably monitor the shelf life of the respective smoked products was determined. Shelf life of vacuum packed smoked eel, trout and salmon at 5 °C was 7.5, 11 and 2 weeks, respectively. LP-17U, M-17U and M-5U enzymatic TTI adequately monitored shelf life of vacuum packed smoked trout fillets, smoked salmon slices and smoked eel fillets, respectively.

Method for catalyst heating control

The aim of the study was the selection of appropriate enzymatic TTIs for quality and shelf life monitoring of ready-to-eat smoked fish products during refrigerated storage. The response of different types of enzymatic TTIs was kinetically modelled and correlated with the quality decay and shelf life of vacuum packed hot smoked eel and trout and cold smoked salmon fillets in the cold chain. The kinetics of shelf life determining quality indices for the tested smoked fish products were established via isothermal experiments. Mathematical models which describe the effect of the enzyme concentration, storage time and temperature on the response of the TTI were developed and validated at variable conditions. The effect of the temperature on the response change of the TTIs was expressed through activation energy and the values were calculated in the range of 80-150 kJ·mol−1. Applying the developed models, the required TTI design to reliably monitor the shelf life of the respective smoked products was determined. Shelf life of vacuum packed smoked eel, trout and salmon at 5 °C was 7.5, 11 and 2 weeks, respectively. LP-17U, M-17U and M-5U enzymatic TTI adequately monitored shelf life of vacuum packed smoked trout fillets, smoked salmon slices and smoked eel fillets, respectively.

Time temperature integrators for monitoring the shelf life of ready-to-eat chilled smoked fish products

Abstract The aim of the study was the selection of appropriate enzymatic TTIs for quality and shelf life monitoring of ready-to-eat smoked fish products during refrigerated storage. The response of different types of enzymatic TTIs was kinetically modelled and correlated with the quality decay and shelf life of vacuum packed hot smoked eel and trout and cold smoked salmon fillets in the cold chain. The kinetics of shelf life determining quality indices for the tested smoked fish products were established via isothermal experiments. Mathematical models which describe the effect of the enzyme concentration, storage time and temperature on the response of the TTI were developed and validated at variable conditions. The effect of the temperature on the response change of the TTIs was expressed through activation energy and the values were calculated in the range of 80-150 kJ·mol−1. Applying the developed models, the required TTI design to reliably monitor the shelf life of the respective smoked products was determined. Shelf life of vacuum packed smoked eel, trout and salmon at 5 °C was 7.5, 11 and 2 weeks, respectively. LP-17U, M-17U and M-5U enzymatic TTI adequately monitored shelf life of vacuum packed smoked trout fillets, smoked salmon slices and smoked eel fillets, respectively.

Not Everything is a Question of Reputation: Safety of Bacteriocinogenic Lab Isolated from Smoked Salmon

Total DNA extracted from bacteriocinogenic and potential probiotic lactic acid bacteria (LAB) (Lactobacillus curvatus ET06, ET30 and ET31, Lactobacillus fermentum ET35, Lactobacillus delbrueckii ET32, Pediococcus acidilactici ET34 and Enterococcus faecium ET05, ET12 and ET88), have been screened for presence of more than 50 genes related to production of biogenic amines (histidine decarboxylase, tyrosine decarboxylase and ornithine decarboxylase), virulence factors (sex pheromones, gelatinase, cytolisin, hyaluronidase, aggregation substance, enterococcal surface protein, endocarditis antigen, adhesion of collagen, integration factors) and antibiotic resistance (vancomycin, tetracycline, erythromycin, gentamicin, chloramphenicol, bacitracin). Tested strains presented low frequencies of presence for virulence genes. Only few genes were detected in some strains, indicating their safety for application in fermented food products. Besides all beneficial properties studied for various LAB, most considered as GRAS, a special attention need to be addressed on the possible presence of virulence factors, production of biogenic amines and antibiotic resistance. Results from appropriate biochemical tests and detected main genes associated to virulence factors and antibiotic resistance in LAB strains, could be considered as potential hazard of application of this organisms in food products. Moreover, additional in vitro and in vivo experiments must be designed in the system simulating GIT conditions in order to investigate deeper the possible expression of the present virulence genes.

Evaluation of ultraviolet light (UV), non-thermal atmospheric plasma (NTAP) and their combination for the control of foodborne pathogens in smoked salmon and their effect on quality attributes

Abstract The effectiveness of UV-C and Non-Thermal Atmospheric Plasma (NTAP) treatments, applied individually or in combination, for the inactivation of Listeria monocytogenes, Listeria innocua, Salmonella enterica serovar Typhimurium, Salmonella enterica serovar Enteritidis, Staphylococcus aureus, Escherichia coli O157:H7, Aeromonas hydrophila and Plesiomonas shigelloides on smoked salmon, compared to an abiotic surface (BHI agar), was evaluated. The impact of these technologies on the color, external appearance and degree of lipid oxidation of vacuum-packaged smoked salmon during refrigerated storage (4 ± 1 °C) for up to 28 days was also determined. D values (mJ/cm2) required to reduce the microbial population in 1 log cycle ranged from 3.12 (S. Enteritidis) to 1.00 mJ/cm2 (P. shigelloides) and t99% values (time of exposure to NTAP needed to inactivate the 99% of the population) ranged between 2.48 (P. shigelloides) and 0.48 (L. innocua) min. Although all microorganisms exhibited a higher resistance to UV-C and NTAP treatments on smoked salmon, the application of a a 900 mJ/cm2 UV-C or a 15 min NTAP treatment allowed the inactivation of −0.5–1.3 log CFU units of the microbial population, with no significant changes in the sensory quality properties of the treated products. The sequential application of UV-C and NTAP resulted in an additive lethal effect, except in combined treatments involving high UV-C energies (500 mJ/cm2) and long (≥4 min) NTAP exposure times, which showed an antagonistic interaction. In addition, these latter combined treatments induced lipid oxidation and adverse changes in appearance. In conclusion, UV-C and NTAP can be considered as promising surface decontamination technologies against foodborne microorganisms of concern in fishery industries, especially for their application on abiotic materials. In addition, they cause minor effects on quality properties of smoked salmon, achieving log reductions ranging from 0.1 to 1.57 when applied in combination, what evidences their potential within hurdle technology approaches aimed at maintaining smoked salmon quality and safety.

Sustainability Descriptive Labels on Farmed Salmon: Do Young Educated Consumers Like It More?

Despite the efforts to make fish sustainable, it is largely unknown if young educated consumers’ taste of fish and their willingness to pay more for fish is influenced by positively framed messages regarding sustainable farming practices. This research investigated if a positively framed description of sustainable farming opposed to positively framed descriptions of flavour, health benefits, or socially responsible farming, influences young consumers’ liking, and willingness to pay for farmed salmon. Young consumers of fish (n = 119) randomly tasted Fresh and hot Smoked salmon and rated their liking and willingness to pay more on structured line scales. The salmon were labelled with either a description of sustainable farming practices, flavour benefits, nutrition/health benefits, socially responsible farming practices, or no descriptions. Descriptive labelling about Sustainability (p = 0.04), Flavour (p = 0.01), and Health/nutrition (p = 0.01) significantly increased consumers’ liking of Fresh salmon compared to Fresh salmon without labelling. No such a difference was found between the social responsibility label and the sample without labels (p = 0.2). Participants were willing to pay more for 250 g of Fresh and Smoked Salmon with descriptive labels (Fresh: $9.3 ± $0.003; Smoked: $10.1 ± $0.003), than for the same Salmon without such labels (Fresh: $9.0 ± $0.06; Smoked: $9.8 ± $0.08) (p &lt; 0.001). The sustainability descriptive label had no added benefit above other descriptive labels. The liking and buying intent were, for all labels and fish types, strongly correlated (r = 0.80, p &lt; 0.001). In conclusion, sustainability labelling is promising, but does not differentiate from other positively framed messages.

Expanding horizons of active packaging: Design of consumer-controlled release systems helps risk management of susceptible individuals

The objective of this study was the development of zein based antilisterial films that contain a consumer-controlled and pH-triggered release mechanism for lysozyme (LYS). For this purpose, composite films were formed by mixing hydrophobic zein with hydrophilic soy protein isolate (SPI) or lentil protein isolate (LPI). Active property of films was formed by maintaining 30 to 50% of total LYS in free form (LYSfree). On the other hand, the pH-triggered release mechanism was formed by exploiting attractive charge-charge interactions between LYS (pI: 11.4) and SPI or LPI (pI values ≈ 4.5), and binding remaining LYS (LYSbound) in film matrix. The pH-triggered release mechanism of composite films worked in buffers that had pHs varying between 4.3 and 7.3. The composite films bound majority of LYS between pH 5.3 and 7.3, but they released LYS at pH ≤ 4.5. The pH-triggered release of LYS was achieved with zein-LPI films activated by acidification in packed cold-stored beef, lamb and smoked salmon. The zein-SPI films performed pH-triggered LYS release in packed food with the exception of packed smoked salmon. The LYSfree and LYSbound released from pH-triggered films showed antimicrobial activity on Listeria innocua. Consumer-controlled release mechanisms enable increasing antimicrobial stress over pathogens during transfer from market to home and cold storage at home. Thus, such films could initiate personalized packaged food to help risk management of susceptible individuals.

Closing gaps for performing a risk assessment on Listeria monocytogenes in ready‐to‐eat (RTE) foods: activity 2, a quantitative risk characterization on L. monocytogenes in RTE foods; starting from the retail stage

Closing gaps for performing a risk assessment on Listeria monocytogenes in ready‐to‐eat (RTE) foods: activity 2, a quantitative risk characterization on L. monocytogenes in RTE foods; starting from the retail stage

Yield and Gel Strength of Gelatin Extracted from Smoked Salmon (Salmo salar) Skins

ABSTRACTThe gelatin yield and gel strength of gelatin extracted from the skins of smoked salmon were determined. The skins had a crude protein content of 43.5 ± 1.2% and an estimated collagen content of 23.6 ± 1.0%. Following an alkali extraction process under varying extraction conditions, the protein content varied from 2.78% to 32.1%, and the gelatin yield ranged from 2.23% to 22.4% of the initial skin weight. The gelatin purity (gelatin/protein) ranged from 55.4% to 100%, with the highest Hyp/protein sample arbitrarily designated as being 100% pure, i.e., an assumption of pure gelatin. Statistical analysis showed that HCl concentration, pretreatment temperature, and extraction temperature significantly affected the protein yield and gelatin yield. The wide range of gel strengths indicates that the gelatin might have been hydrolyzed to different extents during the different extraction and cooling processes. Statistical analysis did not show that any of the factors studied affected the gel strength. However, the data indicated that low NaOH concentrations and HCl concentrations might not prevent hydrolysis during the extraction process. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS–PAGE) showed that the gelatins contained α- and β-chains and that the gelatins composed of higher concentrations of larger molecular weight polypeptide chains had higher gel strengths.

Microbial survey of ready-to-eat salad ingredients sold at retail reveals the occurrence and the persistence of Listeria monocytogenes Sequence Types 2 and 87 in pre-packed smoked salmon

BackgroundAs the preparation of salads involves extensive handling and the use of uncooked ingredients, they are particularly vulnerable to microbial contamination. This study aimed to determine the microbial safety and quality of pre-packed salads and salad bar ingredients sold in Singapore, so as to identify public health risks that could arise from consuming salads and to determine areas for improvement in the management of food safety.ResultsThe most frequently encountered organism in pre-packed salad samples was B. cereus, particularly in pasta salads (33.3%, 10/30). The most commonly detected organism in salad bar ingredients was L. monocytogenes, in particular seafood ingredients (44.1%, 15/34), largely due to contaminated smoked salmon. Further investigation showed that 21.6% (37/171) of the pre-packed smoked salmon sold in supermarkets contained L. monocytogenes. Significantly higher prevalence of L. monocytogenes and higher Standard Plate Count were detected in smoked salmon at salad bars compared to pre-packed smoked salmon in supermarkets, which suggested multiplication of the organism as the products move down the supply chain. Further molecular analysis revealed that L. monocytogenes Sequence Type (ST) 2 and ST87 were present in a particular brand of pre-packed salmon products over a 4-year period, implying a potential persistent contamination problem at the manufacturing level.ConclusionsOur findings highlighted a need to improve manufacturing and retail hygiene processes as well as to educate vulnerable populations to avoid consuming food prone to L. monocytogenes contamination.