Just for general discusion on this topic, the nasty little critters that can cause botulism ( Clostridium botulinum refered to in this post as CB)
are found as spores nearly everywhere. Pressure canning is done to insure that food temps reach a minimum temperature of 240'F (the temperature required to destroy this particular micro-critter. Acidity, and pink salt are both used in dry-cured sausage to do the same thing.
Fortunately for us, the spores are not found usually found in meat tissue, and can only survive and grow in an anaerobic (oxygen free) environment. Other nasty microbes are destroyed between 145 and 165 degrees, depending on the microbe. Sou Vide cooking places the food in an anaerobic environment,
but not long enough forthe CB to grow and cause problems. If you were to home-can green beans, or fish, you could be treading a very dangerous path if not using a pressure canner to reach the proper temperatures.
In roasting, there is oxygen present and so BC is not a risk. The other microbial agents will be killed at anything above 165' F.
Slow and low cooking is a valid way of preparing meat. I have cooked a Boston butt in a covered CI Dutch Oven at 190' for many hours at 190' with wonderful results, and no worries about growing micro-nasties.
Think about drying beef into jerky. You are leaving raw meat, that has been cured in a brining solution, at room tempeartures, or slightly warmer, with moving air, to remove moisture until the meat is dehydrated enough to make it resistant to spoilage (I know, too many prepositions in this sentence
). This usually takes in excess of eight hours. Dried fruits and veggies are done the same way. Low and slow is also great for smoking meats and fish. It takes time to get that great smokey flavor infused into the tissues.
For me though, slow and low is good for only a very few things. I can do in 30 minutes with a pressure cooker, what takes 6-plus hours to accomplish cooking slow and low. I save time, energy, and hassle.
I made a stew just last night with cheep, tough meat, as a practice meal for a pressure cooker class I will be giving next month. Prep, & cook time was a total of 25 minutes, from the time I started peeling spuds and carrots, to the time I served up the stew (ok I took another 5 minutes to make the gravy for the stew after I release the pressure from the PC). The meat had the same texture as if I'd cooked it for hours.
There are always multiple ways to accomplish a desired culinary goal. Think about what you are doing; get the facts from reliable sources (DC is a pretty good place to go for that), and extrapolate from your knowledge base. This will allow you to explore many new, and exciting methods for creating foods that you want to try.
Seeeeeeya; Chief Longwind of the North