I have done a lot of research on sous vide as well as a lot of sous vide cooking. As a technique, it isn't exactly like traditional "low and slow" cooking, since LnS is usually done at braising temperatures. Most of the time with sous vide, you're looking at bracketed cooking times to maintain food safety. You are correct that you can look at the minimum time and temperature and cook to that point. That makes some assumptions about the lineage of your food, though. Let's say that I have some beef that has been improperly stored (in the danger zone between 40 and 140) for 3 hours. If my minimum sous vide cook time for rare at 130 is 100 minutes, that means that I've had meat sitting for over four hours in the food safety danger zone. This is where the time factor comes in... the beef is *cooked* at 130, but in this example it isn't pasteurized. Please bear in mind that this example is contrived because the pasteurization time at 130 is over 100 minutes). Luckily, pasteurization is a factor of both temp and time. If you can't change the temp, then you have to add time to get the same doneness and get over food safety dangers. If you are sure that everything has been stored properly, by all means cook to minimum time and consume short-term. You can also get into trouble if you cook something to a really cool temp for shorter than pasteurization time and don't eat it soon or have a thing for cold leftovers.
That's why most sous vide recipes (reputable ones, at least), will say that you can cook to a doneness in "up to 3 hours and over 8". If you get over 3, you can't take it out until 8... that's purely for pasteurization not doneness, except for really fatty cuts of some meats because certain types of fats go through an intermediate weirdness that isn't tasty, so you're better on the short side or long side, but not in the middle.
Anyways, a few comments back, I was imploring people to pick up some sous vide references because you can get some people seriously sick if you don't know what you're doing. Time and temperature aside, thickness also matters. There are many charts and tables that let you triangulate those three factors to sous vide safely.
I will routinely sous vide fillet mignons for 8 or 10 hours to medium rare out of convenience. They won't be negatively affected ("overcooking", but not really) until hour 18 and it is convenient to just get them done for a dinner party or something. Finish up on the grill and there you go. For other things, like pork belly, they actually do require 24+ hours for the fat to gelatinize at a temperature that keeps the meat parts from being tough.
Anyways, sous vide is great fun but it is a fairly complicated technique and not so much like low and slow as we normally know it. We are a house of crazy kitchen geeks (about to open a gastropub, hopefully
), so I could debate/discuss about this stuff forever. Especially over a home brew!
