Smokeville, I believe your concerns about food safety, as a vendor, are very justified. A few thoughts from a purely food safety and food science perspective.
I think manxman hit the nail on the head when he said " ... it is the whole process from the quality of the original product through to food hygiene in the processing plant...". It is about control. I am not a fish smoker simply because I can't get at any reasonable price fish from a source I trust. If I were to smoke fish today it would be only hot smoked to a food safe temperature for that reason. I envy you folks who have good, reliable sources because I love cold smoked fish.
The big commercial plants employ a lot of controls and processes in an attempt to assure product safety. These start with knowledge and inspection of the incoming catch. There is a lot of sanitation involved including sanitation washes. Microbial testing is used both to assure plant sanitation as well as product safety. In spite of their best efforts there remain product recalls.
A few facts - freezing below 0 °F for a sufficient period of time can kill parasites, and I believe for that reason is now required for cold smoke fish sold in the US. But it won't kill any of the common food borne pathogenic bacteria. To kill requires heat to food safe temperatures. In cold smoking curing, drying and smoking control the grow
of bacteria present to keep them at acceptable levels. After that storage practices determine if those safe levels are maintained. A healthy fish harvested form good waters should have acceptably low levels of harmful bacteria. Following that it is largely dependent on how the fish is handled to keep the levels low and prevent cross contamination.
As far as the cold smoking process goes, commercially it is about keeping bacteria from multiplying. A lot of controls and checks are used to that effort. In the home kitchen it is the same without many of the safeguards that are employed commercially, so the risk is increased. A lot of what we rely on at home is based on being
historically safe, so we continue the practice. For cold smoking curing and drying are the key preservation steps, with smoke being used primarily for flavoring and to keep molds and further contamination at bay during the drying process. The old Alaskan native methods were as much drying methods, to reduce moisture while keeping the product quite cold. The smoking periods were quite long - days. When finished it is still a raw and perishable product unless the fish has been really dried as in something like traditional salt cod.
In the end it is about risk and risk management. If I am doing it for myself, for the enjoyment of myself and my family, that is one thing. I would follow manxman's lead. But for commercial practice, selling it to others, in my mind raises the bar a good bit. Can you assure control from initial fish selection through processing and packaging and be comfortable that what you are offering is a safe product? If so, press onward.
I suspect you may have already read
this publication from the U of Alaska, but I'll pass it along just in case.
Also,
this is the section of the FDA's regulations that establishes the basic safety criteria for seafood (21 CFR 123). Down near the bottom see the section titled "General Guidance for Smoked and Smoke-Flavored Fishery Products". In that you will find the processing requirements for smoked (cold and hot) fish. Note that in those regs do not apply to fish that will be subsequently cooked (which includes the label finnan haddie).
edit I meant to add
this reference too. It is meant to be a guideline for smoking fish in convection smokers, but it provides some of the best, easy to understand, background information about food safety on smoking fish I have found. Note that it is now nearly 10-years old and regulations have probably evolved since then.
