Sous Vide Salmon Safety
Lately on the
sous vide mailing list there has been a discussion about safety with regards to cooking salmon with sous vide, especially when done "mi-cuit" or partially cooked. The two main concerns are the parasite Anisakis simplex and botulism. We try to address some of the concerns here.
As always, please remember:
Sous vide is a new and largely untested method of cooking. It carries many inherit health risks that may not be fully understood. The information on this site is for informational purposes only. Anyone undertaking sous vide cooking should fully inform themselves about any and all risks associated with it and come to their own conclusions. Following anything on this site may make you sick and should only be done if you are fully aware of the potential complications.
This information, as well as over 100 recipes, is available in our book
Beginning Sous Vide which you can get at Amazon.com or as a
pdf download.
Botulism in Sous Vide Salmon
As long as you are eating the salmon as soon as it is done cooking the risk of botulism is very small. This is because the salmon is normally cooked for a short enough period of time that the botulism will not have time to spread. However, if you have the salmon out for over 2 hours then the risk of botulism begins to increase. Feel free to consult the
Practical Guide to Sous Vide for more information on decreasing botulism.
Anisakis Simplex in Sous Vide Salmon
Anisakis simplex is a very common parasite that has been found in around 75% of wild salmon. Normally, salmon is cooked above 140F killing the Anisakis. However, many sous vide salmon recipes call for it to be cooked at lower temperatures, greatly increasing the danger of being infected.
The easiest way to kill the Anisakis parasite is to freeze the salmon before you cook it. Freezing kills the Anisakis and its larve. The FDA guideline is to freeze the salmon at -4F for 7 days and the European Union regulation is -4F for 24 hours.
Before trying to freeze the salmon yourself you should be sure to run a test on your freezer to ensure that it goes at least as low as -4F.
If you are cooking the salmon above 140F then the salmon should be fine and the freezing would be unnecessary.
General Sous Vide Salmon Safety
Douglas Baldwin had
this to say about sous vide salmon safety:
I like
to pasteurize all my fish and shellfish. I do this by cutting the fish
into individual portions and cooking them in a 140F (60C) water bath
for 40--50 minutes. I use 140F (60C) because the fish becomes mushy at
lower temperatures (since it takes much longer to pasteurize) and dry
at higher temperatures (since the muscle fibers contract and squeeze
out the water held between them). I find that 140F (60C) for 40-50
minutes gives safe, moist, and flaky fish.
And from his
Practical Guide to Sous Vide:
While salmon mi-cuit is a popular among sous vide enthusiast, it should never be
served to immune compromised individuals. The low cooking temperatures
in this recipe are not sufficient to reduce the number of food borne
pathogens or parasites. Since the prevalence of the parasite Anisakids
simplex may exceed 75% in various types of fresh U.S. commercial wild
salmon (National Advisory Committee on Microbiological Criteria for
Food, 2008), I recommend either freezing the fish (below –4°F/–20°C
for at least 24 hours) to kill the parasites or pasteurizing the fish
using the times and temperatures in Table 3.5.
He also points out that if you buy sushi grade salmon you can cook it at a lower temperature for a shorter amount of time. However, if he buys sushi-grade salmon he prefers to just eat it raw.
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