Help me understand Sous Vide.

gmac

So I get the basic idea, long slow cooking time with a controlled water bath to hold the temperature.  But, what about food safety?  How do you handle that aspect?  I've always read that between 40F and 140F was dangerous but I'm seeing posts about 130 for 3 days and the like. 

I'd like to give this a try sometime but I want to be sure I fully understand the process etc first.

Thanks

 

The Cen-Tex Smoker

smart to ask- do some reading and you'll get it. 

Good place to start: http://www.douglasbaldwin.com/sous-vide.html

The short story is that you can safely pasteurize food at lower temps within a certain time range (depending on thickness of the food). Everything will eventually die around 130 but it dies instantly at 140. So the idiot's version is that as long as you get your food to a safe temp within the 4 hour window, you can hold it there safely indefinitely. The only thing that changes is the texture of the food. The lonerg it's held there, the more it breaks down. leave it to long and it gets mushy but if you cook to the recommended temps and times, it provides  the most tender juicy food you'll ever eat. 

gdenby

To add a bit more.

When meat is cooked, the muscle proteins "denature," and squeeze out the water held in the tissue. The muscle bundles are held together by collagen, which, when heated, turns into slippery gel. If one can cook the meat in such a way that less moisture is squeezed away, and more collagen is produced, the food will be soft and succulent.

As it happens, pathogens creating toxins grow ever more strongly up to about 126F. After that they begin to die away. As far as I know, there aren't any traditional cooking methods that could reliably hold the food at 130 for the days it took to wipe out the pathogens and also gel the collagen.

attempting an equation, low temp x long time = dead pathogens & low temp x long time = maximum gel.