If you currently feed your dog/pets a balanced raw diet, then you are most likely aware of the importance of supplying an adequate amount of omega-3 fatty acids & vitamin D. A simple way to provide your pet with these essential nutrients, is to incorporate some amount of raw (or deboned, cooked/canned) fish within their diet.
Aside from mackerel and sardines, salmon can be another safe-to-feed fatty fish you can rotate between when meal prepping for your fur babies. For a simple nutrient breakdown of these fish, please see the following post: NDAG- SEAFOOD!
To date, I have not fed raw or canned salmon to my dogs, instead they have eaten lots of mackerel, sardines, the occasional smelt- that's more of a treat, and some thread herring. Salmon canned in water, with no added salt, was difficult for me to find locally and when I did, I thought it was wayy overpriced. I also steered clear of raw wild-caught Alaskan salmon because I was afraid to feed it to my dogs, only for them to later contract salmon poisoning.
If you weren't already aware, salmon poisoning is caused by Neorickettsia helminthoeca bacterium that can be found in a fluke- Nanophyetus salmincola.
Your dog can contract salmon poisoning by ingesting raw fish (including, but not limited to, raw salmon) infected with Nanophyetus salmincola, that most commonly comes directly from the coastal streams of the Pacific Northwest (includes Washington, Oregon, northern California, Alaska & along the Canadian coastline).
Because the thought of my dogs eating infected raw salmon absolutely terrified me, I continued to exclude it from their balanced recipes. That is, until now...
These parasitic flatworms and bacterium can be killed when enough heat is applied to the contaminated fish, hence why feeding cooked salmon from the PNW has always been a safe recommendation.
But what about freezing the fish?
We tend to follow recommendations to freeze any fresh/wild-caught fish for a minimum of 3 weeks before feeding it to our dogs and cats, so why can't we do the same for fish or salmon sourced from the Pacific Northwest? Well, along the way, someone said Neorickettsia helminthoeca and Nanophyetus salmincola were resistant to freezing, therefore cooking would be the only way to kill them, and we all sort of went with it. It is still the safest option, but I wanted to know if there was any overwhelming evidence to support the notion of this fluke and rickettsial organism being freeze resistant. What I found has been shared below...
Does freezing mitigate the risk of salmon poisoning when consuming raw fish (salmon) from the Pacific Northwest (like wild caught Alaskan sockeye)?
It appears so, the minimum critical freezing temperature for processing/storage of raw salmon is at −20°C for 24 hours. When sustained for at least 24 hours, this temperature will destroy Neorickettsia helminthoeca bacterium present in a sample of raw salmon.
Is cooking the only way to kill the parasite?
Per the FDA’s “Hazard Analysis and Risk-Based Preventive Controls for Human Food”, accepted food processing measures to remove biological hazards include using heat, pressure, irradiation, antimicrobial fumigation, refrigeration/freezing, reducing water activity/moisture, reducing pH, adding preservatives, etc. Table 4-3 below lists these process controls further.
Further, microorganisms grow at certain pH ranges, demonstrated by Table 4-15 below.
How does freezing raw fish or raw meat kill parasites? How does that work?
Per Section 4.3.2.2 of the FDA’s Hazard Analysis and Risk-Based Preventive Controls for Human Food, “Foods are microbiologically stable when held at temperatures below 17.6°F (-8°C). During frozen storage, populations of viable microorganisms in most foods will decrease; however, some microorganisms remain viable for long periods of time during frozen storage. Most viruses, bacterial spores, and some bacterial vegetative cells survive freezing unchanged. Some of the other microorganisms are sensitive to the freezing and thawing process (i.e., freezing, frozen storage, or thawing). Since multi-celled organisms (such as parasitic protozoa, nematodes, and trematodes) are generally more sensitive to low temperatures than are bacteria; freezing and frozen storage are good methods for killing these organisms in various foods. This is especially important if consumers are likely to eat the foods raw or undercooked.”
If freezing does kill the parasite found in raw salmon, how cold does the temperature need to be and for how long should it be frozen?
Per the FDA’s “Fish and Fishery Products Hazards and Controls Guidance” (4th Edition, June 2021) :
- Freezing and storing at an ambient temperature of -4°F (-20°C) or below for 7 days (total time)
or
- Freezing at an ambient temperature of -31°F (-35°C) or below until solid and storing at an ambient temperature of -31°F (-35°C) or below for 15 hours
or
- Freezing at an ambient temperature of -31°F (-35°C) or below until solid and storing at an ambient temperature of -4°F (-20°C) or below for 24 hours are sufficient to kill parasites
Note that these conditions may not be suitable for freezing particularly large fish (e.g., thicker than 6 inches).
The temperature of the freezing process, the length of time the fish is held frozen, and the type of parasite appear to be the most important factors towards the effectiveness of freezing on killing parasites. For example, tapeworms are more susceptible to freezing than roundworms. Flukes appear to be more resistant to freezing than roundworms.
A study titled, “Rickettsiosis, Ehrlichiosis, Anaplasmosis, and Neorickettsiosis” by Robert G. Sherding concluded that freezing at −20°C for 24 hours, or thoroughly cooking salmon destroys rickettsiae parasites, which coincides with the FDA guidelines above.
Concluding Thoughts
A parasite can be a bacterium, virus, fungus, etc.
A parasite is defined as an organism that uses a host organism for survival. The term describes the function of an organism rather than its biological identity or classification.
Canids are affected by the Neorickettsia helminthoeca bacterium, for which the trematode Nanophyetus salmincola is the vector/carrier and not the parasite itself. If a dog ingests raw fish containing Nanophyetus salmincola that are infected with Neorickettsia helminthoeca, salmon poisoning will occur.
Fluke- Nanophyetus salmincola: attaches to your dog’s intestines and begins feeding
Rickettsial organism- Neorickettsia helminthoeca: released into your dog’s bloodstream and is carried throughout the dog's circulatory system
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I'm still scared to feed my dog raw salmon from the PNW, what should I do?
If you do not want to feed your dog or dogs, raw fish that comes from the Pacific Northwest, then don't. Continue to feed deboned, cooked salmon or other fatty fish, like mackerel or sardines.
If you need to feed canned salmon, look for those packed in water with no added salt or flavouring! Canned salmon will already be cooked, so there is no need to cook it further.
Can I freeze raw fish or raw salmon in my normal freezer (refrigerator freezer)?
Most refrigerator freezers are kept at -18ºC (0ºF).
Per the FDA’s “Fish and Fishery Products Hazards and Controls Guidance,” that would not be cold enough to kill the fluke or bacterium. If your freezer settings are adjustable and you are able to lower the temperature and follow the FDA's guidance, THEN it may be okay to use your regular freezer.
For chest freezers and upright freezers, settings vary, but on average, the lowest temperature setting seems to sit around -23ºC (-10ºF) for most models. Double check the specifics for the size and model you have before using it to freeze any fish or meat.
Can humans get salmon poisoning?
To date, canid species are the only species susceptible to salmon poisoning. But this does not mean humans won't experience any gastrointestinal illness from consuming contaminated fish from the Pacific Northwest.
If I purchase raw Alaskan sockeye salmon that has already been frozen, do I still need to freeze or cook it?
If you are sourcing raw Alaskan salmon from a trustworthy source and you are able to verify the fish has in fact been frozen at the correct temperature for an appropriate amount of time, then technically, no, you would not need to freeze or cook it.
If you are ever unsure of the quality or freezing methods of the fish, I would probably discontinue sourcing from said party. If I have to second guess my source or the quality of the meat/fish, then I'm not comfortable purchasing from them, full stop. Alternatively, if you just want to be as safe as possible, you can absolutely still cook the fish or freeze it at the appropriate temperature for 3 additional weeks, before feeding it to your dog.
Should I freeze my raw fish or raw salmon for only 24 hours, per FDA guidance?
I would still continue to follow the general recommendation for freezing all raw fish that has not been previously frozen, for a minimum of 3 weeks!
Better to be safe than sorry.
**IMPORTANT NOTE**
Even though your freezer may be able to reach and maintain a certain temperature, that does not guarantee the meat or fish being frozen/stored in the freezer will reach and/or maintain that set temperature throughout. Bear this mind when freezing all raw fish and meat, as your fur baby could still be at risk.
References
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Please consult physicians/veterinarians, and/or other trustworthy science-based sources for advice on human and animal dietary questions.
Hope this was helpful to some!
Follow me on instagram @nolorlin for more raw feeding content & recipes!
xoxo
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