A great chef once told me:
“Put down your science for a moment and just imagine this. In a vacuum bag you put a beautiful octopus, add organic olive oil, a little bit of lemon zest, and some fresh aromatic herbs to create a wonderful flavor. You then use a vacuum sealer and sous-vide for 45 minutes at a high temperature. When you take it out of the water bath, you will have a perfectly cooked and flavored octopus, tender and delicious.
Because what happens when you sous-vide is that the flavor really gets injected into the core of the product and it seasons it. It’s not just what we call surfaced season but it’s seasoned thoroughly. The texture, the flavor, the smell will be cooked perfectly every time. I will be serving an incredible dish”
She had a lot of great ideas for sous-vide clams, salmon, octopus, and all kinds of seafood. However, as I started writing her HACCP plan for sous-vide I had to tell her “no, you can not use this slow cooking process for seafood.” I know she was disappointed. Of course the dish sounds delicious. Of course it will yield perfect results. But the real issue is if it’s safe.
Even when sous-vide is a cooking technique that results in amazing dishes, the truth is that its use is not always safe because it implies the modification of the food environment by reducing the oxygen that surrounds it.
Reduced Oxygen Packaging (ROP) extends food shelf life and inhibits the growth of spoilage aerobic microorganisms as Bacillus subtilis or Listeria spp. But, what about anaerobic microorganisms?
Clostridium botulinum is an anaerobic bacteria that has been found in the gills and viscera of finfish, crabs and shellfish. The cells of C. botulinum are easily killed by heat. However, this pathogen is able to produce spores that are very resistant to heat. C. botulinum produces the highly dangerous botulinum toxin. The toxin is so potent that 3 kg are enough to kill off the entire population of California (40 million people).
The reduced oxygen environment in packaged fish and fishery products increases the potential for the formation of C. botulinum. Furthermore, this bacteria forms toxins more rapidly at higher temperatures than at lower temperatures.
One way to avoid the presence of C. botulinum when reduced oxygen packaging raw seafood is keeping the food frozen before, during and after being packaged. The freezing temperature inhibits the C. botulinum growth, but also eliminates the opportunity to sous-vide seafood.
Scientists are experimenting with sous-vide seafood in search of a way to make it safe by controlling C. botulinum growth. But for now, in the realm of sous-vide cooking, avoiding sous-vide seafood is the best practice for food safety and HACCP.