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pierino is a trusted source on General Cooking and Tough Love.
You will need more than a vacuum sealer for sous vide. You will also need an immersion circulator and lots of liability insurance. Feeling lucky? And I'm being serious. These things don't belong in home kitchens unless you are total pro---and even the pro's screw up on this. It's hip, it sounds smart but unless your last name is Dufresne keep your distance.
Before you invest in sous vide equipment or delve deeply into this cooking method, I would do a lot of reading and listening first. We love the Cooking Issues podcast on the Heritage Radio Network (http://www.heritageradionetwork...). It can be incredibly technical but is totally fascinating if you're interested in food science and technical food/cooking issues. AND you can email, tweet, or call in questions to the show, and they will most likely answer them. Very knowledgeable folks. Oh, and last week on the show, Dave Arnold reported that he spoke directly with someone from P&G about their Ziploc bags, and apparently, they're safe for sous vide cooking. I still don't know if I would want to use Ziploc bags often for sous vide, but it does seem that if P&G is willing to stick its neck out and ok it, they probably aren't kidding.
I would also do some reading. Under Pressure by Thomas Keller is a beautiful but intimidating book. It's clearly written for chefs or people with tons of time and money on their hands. Ditto Modernist Cuisine--it has a lot of good things to offer, but it's really prohibitive for a home cook just starting out with sous vide. Modernist Cuisine At Home is better, but that's still going to run you $100. You might refer to the Sous Vide Cooking Reference Guide for help (http://www.sousvidesupreme...). Also check this out: http://www.cookingissues...
As an aside, killing bacteria can be accomplished a couple different ways--higher heat for a shorter time or lower heat for a longer time. Sous vide uses the latter principle. Also, sous vide often relies upon a quick sear after cooking, since you're not going to get any tasty Maillard reactions (browning) during sous vide cookery. This searing process also helps to kill bacteria.
The safety concerns that Pierino hinted at are very real, though. If you're going to experiment with sous vide cooking, do it in the most cautious and educated manner possible. Read everything you can get your hands on, listen to experts, and always be skeptical--research this for yourself rather than relying solely on anecdotes. Learn about the temperatures and times required to kill bacteria (botulism, for instance, which is a concern for anaerobic cooking methods, takes 8 hours at improper holding temps--between 40-140F--to develop into the bacteria that can harm or kill you). Also, use common sense. Don't take chances, and if something doesn't seem right to you, don't eat it. Also remember that there are only about 145 cases of botulism in the US per year, over half of those cases are infant botulism and about 20% of cases are from wounds. Most of the foodborne cases are from home-canned foods, but no-one's telling you not to preserve foods. So, my point is, educate yourself, don't freak out, but don't be a moron either.
And after saying all that, I would advise children, the elderly, pregnant women, and those with compromised immune systems not to eat food cooked sous vide. That's just a standard precaution that I think bears repeating.
Thank you for the comprehensive answer to James's question, Petitbleu. I just received a sous vide supreme rig for my birthday, and getting started is fairly daunting!
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