What exactly do you mean by this? Do you mean that if the meat is from a reputable source that the risk of food borne illness is pretty small?
My initial reasoning for opening this thread was that I hate it when I am cooking a roast or any type of meat and I am not 100% sure that it is at the proper temperature (like sometimes my thermometer will say 140 or so for pork or 120s for salmon and I am not sure if it's safe). So I just want to know how much I should be concerned for things like that. Along those lines, whenever I eat a piece of meat that I feel is questionable in terms of whether it was as done as it should have been, I wonder how long it is until I am "clear" or if illness could still occur.
Wasn't getting into reputable sources at all. Just meant that if it isn't contaminated in some way. For the person cooking it, pretty much just food handling and storage techniques. Very few of us actually know how the food is handled up until the time we receive it so you are somewhat limited by sight and smell of the meat/fish. I assume that we all generally only buy food from places we feel are reliable.
Fish and steak (beef, lamb and presumably veal, venison and other meats) can be served rare, cured or even raw. Pork used to need to be cooked thoroughly but over here in Oz, it is now being marketed that it may be cooked to medium-rare, although most still aren't comfortable with the concept. (I don't eat pork though so my knowledge is limited.) Poultry that isn't properly cooked I would be more suspicious of.
I don't use a meat thermometer but look at the juices instead and use a skewer. It isn't how I was taught to cook and I haven't felt the need to use one, although I do have a meat thermometer somewhere...
Also when cooking a roast, keep in mind that the meat continues to cook a little while it rests, esp when talking about seafood. I eat lots of meats/seafood either raw or done as a cerviche or other semi-cured style. And it isn't the most likely way that I will get ill if the ingredients are good. If you are carving a roast and discover a bit that you think is too undercooked, cut around it as you can put it back in the oven to finish cooking without worrying about your diners.
If you are confident of the ingredient before cooking it, then being out a couple of degrees I wouldn't have thought would be an issue but maybe someone who uses a thermometer will be better to clarify that point.
As already mentioned, the time taken to incubate the organism/bacteria enough to show food poisoning symptoms will depend on the organism/bacteria as well as your tolerence. When I got sick, I had next to no tolerance as I was really run down having been super busy at work and super stressed having my position dissolve underneath me!! Different time, I may have been able to resist the bug better.