The Library Guides

- Fish and shellfish smoking business issues

This Library Guide has been started to provide information on how to set up and manage a small seafood smoking business. It will evolve over time and will gradually be populated by relevant information as we work with a small group that is trying to establish themselves as a seafood smoking business.

Please feel free to offer suggestions, ask questions or provide the answers needed to make this Guide (and the business) a success. The information we gather here will help other businesses to become established. Are you on our smoking email list? If not then send an email and we'll put you on.

NB: As Library Guides are quick-response, semi-formal products they will occasionally contain errors which we will seek to correct. The information contained in them is for Guidance only and we cannot be held responsible for decisions made using the Guides.

Information leaflets Documents DVDs and Videos Presentations Technical Questions

Q1. My EHO insists on a 5 day shelf life on cold smoked salmon. Why?

A. Perhaps as smoked salmon is a Ready To Eat (RTE) Food it falls under a GMPG Guide on shelf life of RTE Foods with regard to Listeria. If the shelf life of the product is 5 days or less it doesn't fall under the Guide. Other 'exclusion criteria' are that the smoked salmon (or other RTE product) has a water activity less than 0.92 AND the product has less than 20cfu/g of Listeria after production and less than 100cfu/g at the end of its shelf life. If that is the case then you may well be able to safely give a longer shelf life to your product. As the Food Business Operator (FBO), it is your responsibility and if you consult the following resources then you will be better placed to make the right decision re shelf life.

NB: You may decide that the end of the smoking process (and when the shelf life clock starts ticking) isn't when the salmon leaves the kiln, but when it is sliced after maturation.

RTE Shelf Life Online Guidance CFA March 2010

Shelf life guidance in relation to Listeria: 2010 (as pdf)

2002 Publication by the US National Fisheries Institute on Listeria

Lecture on Listeria

Guidelines for Setting Shelf Life of Chilled Foods in Relation to Non-proteolytic Clostridium botulinum (July 2018)


Q2. What are PAHs and why should I care?

A. Polycylic aromatic hydrocarbons (PaH's) form a large group of chemicals, some of which are known to be toxic. They are produced largely by combustion processes and are present in small amounts in smoked foods. Seafish 2003 PAH Report

Q3. My bacterial counts seem too high and varies for no apparent reason - what might be the cause and solution?

A. suggestions from food managers or EHOs etc welcome to

Q4. Is it permitted to use liquid smoke? Is it a way of producing good quality smoked products?

A. See this FSA page for more information on the legality. In our view liquid smoke is a quick way of producing low quality smoked-style products. see also this regulation.


Have you a question to ask? Email


Other Useful Compliance Information

What issues should I consider when setting up a seafood smoking business - outline response from a Seafish Adviser

How to produce safe smoked fish - Food Standards Scotland toolkit - highly recommended.

Listeria - this Canadian Policy document is very useful and an interesting comparison with the information available from the FSA.

Shelf life guidance in relation to Listeria: 2010 from the Chilled Foods Association (local copy - please use link above for the version on the CFA website)

The main food safety risk from chilled ready to eat seafood such as smoked salmon and some other fish and shellfish products would appear to be from Listeria, although Clostridium can be an issue for some products and low oxygen packaging. Sealed packaging packed smoked fish and shellfish should always be packed in an oxygen permeable material to reduce the risk of anaerobic bacterial multiplication. Vacuum packed and modified atmosphere packed products have their own requirements to ensure food safety is not compromised.

- Overview of Listeria

The bacterial genus Listeria currently comprises 10 species, but human cases of listeriosis are almost exclusively caused by the species Listeria monocytogenes (L. monocytogenes). Listeria species are ubiquitous organisms that are widely distributed in the environment, especially in plant matter and soil. The principal reservoirs of Listeria are soil, forage and water. Other reservoirs include infected domestic and wild animals.

The main route of transmission, to both humans and animals, is through consumption of contaminated food or feed. The bacterium can be found in raw foods and in processed foods which are contaminated after processing. Infection can also rarely be transmitted directly from infected animals to humans. Cooking at temperatures higher than 65 °C destroys Listeria, but the bacteria are able to multiply at temperatures as low as +2/+4 °C, which makes presence of Listeria in ready-to-eat (RTE) foods, with a relatively long shelf-life, of particular concern.

- Clostridium botulinum

Capable of producing a toxin which can be fatal and which may not be destroyed during normal cooking. Multiplication takes place in reduced oxygen conditions (canned or sealed plastic pouches for example) but the risk is much reduced if product is kept chilled, below 5C. The risk is also reduced in products that have sufficient levels of salt, nitrite and smoke chemicals. reduced water activity 0.85 - 0.99 are typical for smoked fish. To achieve this appropriate brining, adequate drying during handing and smoking must be achieved by the smoker. See p5 of the Oregon State Guide for detailed specifications, which are summarised below,

Source = FDA 2001 Guidelines

Cold-Smoked Fish (Oxygen Permeable Packaging) - No guidelines; treat as fresh fish

Cold-Smoked Fish (Reduced Oxygen Packaging) - The smoker temperature must not exceed 32.2ºC

Hot-Smoked Fish (Oxygen Permeable Packaging) - No guidelines; treat as cooked ready-to-eat fish

Hot-Smoked Fish (Reduced Oxygen Packaging)
• The internal temperature of the fish must be maintained at or above 62.8ºC throughout the fish for at least 30 min
• Not less than 3.5% water phase salt in the loin muscle, or, where permitted, the combination of 3.0% water phase salt in the loin muscle and 100-200 ppm nitrite.

• The product must not be exposed to temperatures above 10ºC for more than 12 h nor to temperatures above 21.1ºC for more than 4 h, excluding time above 60ºC
• The product must not be exposed to storage temperatures above 10ºC, which may be assured by:
o A maximum cooler temperature of 10ºC ; and/or
o The presence of sufficient cooling media (e.g., adequate ice to completely surround the product)
• The product must not be exposed during transportation to temperatures above 10ºC, which may be assured by:
o A maximum refrigerated container temperature of 10ºC throughout transit;
o The presence of sufficient cooling media (e.g., adequate ice to completely surround the product) upon receipt


Step 1: Try our comprehensive Study Guide on Smoking.

The study guide provides access to learning materials, information on HACCP, older Torry Advisory Notes and more recent publications.

Hot smoked fish and shellfish and cold smoked salmon are Ready To Eat (RTE) foods. RTE foods require high care and may fall under good manufacturing guidance published by the Chilled Food Association in 2010. Consequently you will need a HACCP plan in place and will need to demonstrate staff training, instruction and/or supervision. Are you ready? If not then we can certainly help with food safety training at levels 2 and 3. For more information try here.

A level 3 VRQ on smoking - information here

Information on smoking courses available from Seafish approved trainers.


Business Advice Section


Have you a question to ask? Email


Publications List

Weidmann, Martin and Ken Gall. Listeria monocytogenes: A challenge for the smoked seafood industry in International Smoked Seafood Conference Proceedings, Alaska Sea Grant College Program Publication AK-SG-08-02, University of Alaska, Fairbanks, 2008, Pages 1-4.

Gall, K., VN Scott, R. Collette, D. Hicks, and M. Wiedman. Implementation of Listeria Controls by Ready-to-Eat Seafood Processors Following a National Workshop Series, Food Protection Trends, Vol. 26, No.2, 2006, Pages 89-95.

Hu, Y. K. Gall, A. Ho, R. Ivanek, Y. T. Grohn, and M. Weidman. Daily Variability of Listeria Contamination Patterns in a Cold-smoked Salmon Processing Operation. J. Food Prot. Vol. 69, No. 9, 2006, Pages 2123-2133.

Industry Collaboration Advances Listeria Control in RTE Seafood Plants: An Interview with Ken Gall, New York Sea Grant and Smoked Seafood Working Group. Food Safety Magazine, Vol. 11, No.4, August/September 2005, Pages 52-55 and 63-66.

Scott, VN, M. Wiedmann, D.Hicks, R.Collette, M. Jahncke and K. Gall. Guidelines for Listeria Testing of Environmental, Raw Product and Finished Product Samples in Smoked Seafood Processing Facilities, Food Protection Trends, Vol. 25, No 1, 2005, pages 23-34.

Hicks, D, M. Weidmann, V. N. Scott, R. Collette, M. Jahncke, and K. Gall. Minimizing Listeria Contamination in Smoked Seafood: Training Plant Personnel. Food Protection Trends, Vol. 24, No. 12, 2004, Pages 953-960.

Jahncke, M, R. Collette, D. Hicks, M.Wiedmann, V.N. Scott, and K.Gall. Treatment Options to Eliminate or Control Growth of Listeria monocytogenes on Raw Material and on Finished Product for the Smoked Fish Industry. Food Protection Trends, Vol.24, No.8, 2004, Pages 612-619.

Lappi, VR, J. Thimothe, K. Nightingale, K. Gall, V.N. Scott and M. Wiedmann. Longitudinal Studies on Listeria in Smoked Fish Plants: Impact of Intervention Strategies on Contamination Patterns. Journal of Food Protection, 2004, Vol. 67, No. 11, Pages 2500-2514.

Lappi, VR, A. Ho, K. Gall and M. Wiedmann. Prevalence and Growth of Listeria on Naturally Contaminated Smoked Salmon Over 28 Days of Storage at 4 degrees C. Journal of Food Protection, 2004, Vol. 67, No. 5, Pages 1022-26.

Lappi, V.R., J. Thimothe, J. Walker, J. Bell, K. Gall, M.W. Moody, and M. Wiedmann. Impact of Intervention Strategies on Listeria Contamination Patterns in Crawfish Processing Plants: A Longitudinal Study. Journal of Food Protection, 2004, Vol. 67, No. 6, Pages 1163-1169.

Gall, KL, V.N. Scott, R.Collette, M. Jahncke, D. Hicks and M. Wiedmann. Implementing Targeted Good Manufacturing Practices and Sanitation Procedures to Minimize Listeria Contamination of Smoked Seafood Products. Food Protection Trends Vol. 24, No. 5, 2004, Pages 14-27.

Thimothe, J, K. Kerr Nightingale, K. Gall, V.N. Scott and M. Wiedmann. Tracking and Control of Listeria monocytogenes in Smoked Fish Processing Plants. Journal of Food Protection, Vol. 67, No. 2, 2004, Pages 328-341.

Hoffman, AD, Gall, KL, Norton, DM and Wiedmann, M. Contamination Patterns in the Smoked Fish Processing Environment and for Raw Fish, Journal of Food Protection, Vol. 66, No. 1, 2003, pages 52-60.

Adam D. Hoffman, Kenneth L. Gall and Martin Wiedmann, The Microbial Safety of Minimally Processed Seafood with Respect to Listeria monocytogenes in Microbial Safety of Minimally Processed Foods, Edited by John S. Novak, Gerald M. Sapers and Vijay K. Juneja, CRC Press, Boca Raton, FL, 2003, Pages 53-75.

Thimothe, J, J. Walker, V. Suvanich, K. Gall, M. Moody, and M. Wiedmann, Dectection of Listeria in Crawfish Processing Plants and in Raw, Whole Crawfish and Processed Crawfish (Procambarus spp.), Journal of Food Protection, Vol. 65, No. 11, 2002, Pages 1735-39.

Norton, DM, M.McCamey, K. Gall, J. Scarlett, K.Boor, and M. Wiedmann, Molecular Studies on the Ecology of Listeria monocytogenes in the Smoked Fish Processing Industry, Applied and Environmental Microbiology, Vol. 67, No. 1, 2001, Pages 198-205.