Course:FNH200/Projects/2025/Smoke Salmon - Process, safety and regulation
Introduction:
Smoked salmon is a popular food product that can be incorporated into a healthy diet when consumed in moderation. Unlike fresh salmon, smoked salmon undergoes additional processing, including curing with salt to remove moisture, followed by a smoking process. These processes not only enhance flavour and texture but also extend the product’s shelf life.
This research project examines the food science behind smoked salmon, with a particular focus on the smoking process, associated safety considerations, and recommended handling and storage practices. The findings highlight how specific processing methods can significantly alter the texture, flavour, and overall physical and chemical properties of a food. Our investigation centres on Premium Seafoods Wild Smoked Sockeye Salmon, see picture below for reference, and the research presented is catered specifically to this product.
The Making of Smoked Salmon:
The Smoking Process
Thawed, boneless salmon is first cured with salt and sugar, which draws out moisture, enhances flavor, and inhibits bacterial growth. After curing, the salmon is dried to form a pellicle which is a thin, translucent protein layer that allows smoke to adhere during the smoking process. The salmon is then smoked using wood chips from trees such as oak, maple, hickory, or alder. There are two smoking methods: cold smoking and hot smoking. Cold smoking occurs at temperatures between 10 and 32 degrees Celsius and in contrast, hot smoking heats the salmon to an internal temperature of 63 degrees Celsius (Walle, 2020).
Key Reactions
During curing, salt and sugar draw out moisture from the salmon through osmosis, reducing water activity and inhibiting bacterial growth. This process initiates protein denaturation, which firms the flesh and begins flavour development. Hot smoking applies heat that further denatures proteins, fully cooking the salmon and creating a flaky texture. Cold smoking uses lower temperatures that preserve a smooth, raw-like texture while allowing smoke compounds, particularly phenols such as guaiacol and syringol from hardwoods, to penetrate and bind to the pellicle along with imparting the characteristic smoky aroma. The Maillard reaction, occurring only during hot smoking, produces browning and savory roasted flavors. Finally, controlled lipid oxidation reactions during storage can also enhance umami flavor (Yu et al., 2020).
Texture, Flavour, and Appeal
As moisture is lost and proteins denature during curing, the salmon’s flesh becomes firmer and denser, with a slightly chewy mouthfeel. Cold smoking preserves a raw appearance that is visually appealing (Shallcross & University of Alaska Fairbanks, 2022). The final flavor profile is complex, combining smoky, salty, subtly sweet, and umami notes. Premier Seafoods’ Wild Smoked Sockeye Salmon attains its distinctive rich reddish color, silky texture, and complex flavor through traditional curing and smoking methods, including the use of salt, brown sugar, and alder wood smoke (Bradley Smoker, 2023). According to Premier Seafoods online advertisement, their cold smoked sockeye salmon “has a silky finish yet firm texture, rich in flavour and a dark reddish colour” (Premier Seafoods, 2024).
Additionally, smoked salmon in particular is prized for its rich umami flavor and unique smoky aroma, as well as its nutritional benefits including being high in omega-3 fatty acids, quality proteins, and vitamin B (Haas, 2024). Because it is cured and vacuum-sealed, smoked salmon is convenient and ready to eat.
Smoked Salmon Safety:
Potential Safety Concerns
The food safety regarding cold-smoked salmon has been carefully regulated to ensure consumers safety. According to Government of Canada Guidance Document on Ready-to-Eat (RTE) Smoked Fish (Government of Canada, 2018), two of the main concerns of food-borne pathogens for RTE cold-smoke fish are Clostridium Botulinum (C. Botulinum) and Listeria Monocytogenes (L. Monocytogenes). Beside the bacteria contamination, parasites are also a cause of concern. As such, the Canadian Food Inspection Agency (CFIA) provides regulatory guidance to reduce these risks in RTE smoked fish products.
Elimination/Control of the Risk Factor
Parasite Control
Inadequately cooked or improperly processed fish infested with Anisakis parasite species can pose health risks to humans. Parasite infestation can be effectively eliminated by freezing/cooking. Specifically, for cold smoked salmon, regulatory agencies require that fish be frozen to precise temperatures for set durations before being consumed raw or cold-smoked. For example, freezing at -20°C for 7 days or -35°C for 15 hours is considered effective for killing parasites (Government of Canada, 2018).
Mitigation of Pathogenic Bacteria
As previously addressed, C. Botulinum and L. Monocytogenes, are major concerns among pathogenic bacteria–particularly because the standard 6D/12D lethality treatment is not applicable to cold-smoked salmon products (Eugene, 2024). It is critically important to proactively prevent the growth of C. botulinum from the early stage of food processing. Refrigeration below 4.4 C and /or freezing after harvest along with steps such as scale removal and evisceration, are some of the measures recommended in Enugene’s article to minimize the risk of toxin formation by C. botulinum. To control and minimize the growth of L. monocytogenes, thorough sanitation across the entire food production chain–including harvesting areas, vessels, transportation vehicles and processing facilities–is essential. His article also adheres to the guideline established by the Government of Canada. Eugene went through great detail on how the process of smoked-salmon itself can be used to mitigate the pathogenic bacteria concerns. For example, the initial salt and sugar curing step is not only used to enhance the flavor and texture of the product but also plays a role in drawing out moisture and creates an environment less favorable for bacterial growth.
Many cold-smoked salmon products are vacuum sealed to reduce oxygen exposure, thereby extending shelf life by limiting the growth of aerobic bacteria. However, It is important to note that both C. Botulinum and L. Monocytogenes can grow anaerobically. As a result, vacuum-sealed packaging can still support its growth, which makes strict control measures during processing all the more critical to ensure product safety (Government of Canada, 2018). An advanced, non thermal technique, high pressure processing (HPP), can significantly reduce microbial loads—including Listeria— while preserving the texture and quality of cold-smoked salmon. Studies show that HPP can extend shelf life by about two weeks (Erkan et al., 2011)
Recommended Consumer Practices for Safe Handling and Storage
The end consumer plays a critical role in controlling the risk of eating contaminated products. Firstly, continuing to keep the smoked salmon product refrigerated in temperatures lower than 4°C is crucial to inhibit the microbial growth, as the cold temperatures can hinder the function of the enzymes. Secondly, it is recommended for buyers to consume the smoked salmon before the best-before date that is labelled on the packaging in order to minimize the risk of consuming spoiled product. Thirdly, it is highly recommended to avoid refreezing smoked salmon that has already been thawed. In British Columbia, sampling for L. Monocytogenes in food products is not mandatory for food processing facilities licensed under provincial authority. However, a study was conducted to estimate the prevalence of L. Monocytogenes in ready-to-eat (RTE) foods. The result showed that fish products from 5 out of 12 BC fish processing facilities tested positive for the bacterium (Kovacevic et al., 2011). Due to the potential risk of exposure to pathogens before packaging, repeated freezing and thawing of the product, even without opening the package, can promote microbial growth, and therefore is not recommended.
Conclusion:
Smoked salmon is a cherished delicacy that combines tradition with modern food science. While cold-smoking imparts exceptional flavor and texture, it also presents unique safety challenges. By combining proper handling practices, stringent regulatory oversight, and innovative interventions such as high-pressure processing, producers can safeguard the quality and safety of this ready-to-eat product. Ultimately, consumer awareness and adherence to correct storage and usage guidelines are equally essential to ensuring that smoked salmon remains both a pleasure to eat and safe to enjoy.
References:
Bradley Smoker. (2023, January 12). Alder Flavor Profile: The Most Delicate, Earthy Wood Smoke. Bradley Smoker. Retrieved August 10, 2025, from https://www.bradleysmoker.com/blogs/articles-smoking-guide/alder-flavor-profile-the-most-delicate-earthy-wood-smoke
Erkan, N., Uretener, G., Alpas, H., Selcuk, A., Ozden, O., & Buzrul, S. (2011, April). The effect of different high pressure conditions on the quality and shelf life of cold smoked fish. Innovative Food Science & Emerging Technologies, 12(2), 104-110.
Eugene, E. (2024, Dec 19). Understanding hot and cold smoked fish processing and safety. Food Safety Magazine. https://www.proquest.com/trade-journals/understanding-hot-cold-smoked-fish-processing/docview/3190048444/se-2
Government of Canada. (2018, Oct 17). Guidance Document on Ready-to-Eat Smoked Fish and Multi-Ingredient Products Containing Smoked Fish. Retrieved August 4, 2025, from https://www.canada.ca/en/health-canada/services/food-nutrition/legislation-guidelines/guidance-documents/smoked-fish.html#a1
Haas, S. (2024, August 7). Is Smoked Salmon Healthy? Here's What a Dietitian Says. EatingWell. Retrieved August 10, 2025, from https://www.eatingwell.com/article/7892708/is-smoked-salmon-healthy/?utm_source=chatgpt.com
Inside. (2018, Sept 18). How Smoked Salmon Is Made [Video]. Youtube. https://www.youtube.com/watch?v=HxiyDCWHMTs
Kovacevic, J., F. Mcintyre, L., B. Henderson, S., & Kosatsky, T. (2011). Occurence and Distribution of Listeria Species in Facilities Producing Ready-To-Eat Foods in British Columbia, Canada. Journal of Food Protection, 75(2), 216-224.
Premier Seafoods. (2024). Cold Smoked Salmon. Premier Seafoods. Retrieved Aug 10, 2025, from http://www.premierseafoods.ca/cold-smoked.html
Shallcross, L., & University of Alaska Fairbanks. (2022, May). Smoking Fish at Home. Cooperative Extension Service. Retrieved Aug 10, 2025, from https://www.uaf.edu/ces/publications/database/food/smoking-fish.php
Walle, G. V. D. (2020, January 31). Smoked Salmon: Nutrition, How It's Made, and More. Healthline. Retrieved August 10, 2025, from https://www.healthline.com/nutrition/smoked-salmon-calories
Yu, Y., Yang, S. P., Lin, T., Qian, Y. F., Xie, J., & Hu, C. (2020, Sept). Effect of Cold Chain Logistic Interruptions on Lipid Oxidation and Volatile Organic Compounds of Salmon (Salmo salar) and Their Correlations With Water Dynamics. Frontiers in Nutrition, 7(00155), 155. 10.3389
Exam question:
Question
After curing the fish, the forming of what through the drying process was important for flavor development during smoking:
A. Pellicle
B. Dried fish skin
C. Scale
Answer: A
Why: This was a new knowledge we learned as a team. It was interesting to know that denatured protein could play a critical role to bring in diversity of food choice through different processes. I wonder if this is the same reason why the meat made by camp fire always have an extra special taste add to it.