Like, basically worst case, it was tainted with some sort of bacteria that managed to grow on the meat and create a significant enough amount of toxic compounds to give you food poisoning symptoms, somehow all entirely without giving off any discernible smell?

Well yeah, basically. I've heard of numerous different cases where lots of people got really sick or died eating meat (especially pork) that didn't smell or seem bad. The bacteria that makes meat smell bad isn't necessarily always the same that poisons you.

https://now.tufts.edu/articles/food-bacteria-smell-taste-bad-illness