My rule is, and I learned it the hard way, twice, is that if it tastes off, stop eating it and toss it.
About 39 years ago, I got some food at a popular chain of fast food places that I won't name. I bought two sandwiches for me to eat then, one for my dogs to split, and 2 more to freeze for the future. I ate mine, and they just tasted slightly off. They didn't smell funny, or anything else. I tore the one for the dogs in half and they scarfed it down. I felt ok for a while, and then suddenly both dogs, at almost the exact same time, threw the sandwiches up. I didn't think it was a coincidence. I went into the bathroom and made myself puke. Too late. I spent about the next 24 hours on the toilet with a bucket in my hands. It was horrible. After it was over, I avoided the place for several months, and then one night, I just didn't feel like driving to the closest other one, and I did a very stupid thing, I went and got the same exact order as before. The second time, it lasted 36 hours and my girlfriend begged me to let her take me to the ER, but I refused. It ended just like the first time, I was going both ends and then it stopped. I told her it was over, and she asked, "How do you know?". I don't know, but I did. I drank a gallon jug of water, and went to sleep for about 14 hours. I woke up and cooked myself and the dogs a huge pot of hamburger and rice (One of my dogs would kill for it, he just loved it). I stuffed myself and the dogs did too, and I went back to sleep for another 12 hours. For 3 years I avoided the chain, even though it was my favorite fast food place, but after we came back to Ohio, I went back and as far as I know, it hasn't made me sick since. If it happened today, I would definitely go to the ER, and after I got out, I would find the closest lawyer and sue away. I doubt I would survive it again, to be honest about it.