I am glad you are talking to your therapist about this because it sounds like you hit a trigger. You need some concrete techniques to move on. Food is problematic for me as well, for other reasons, so I can empathize. But I can tell you that having a good therapist that helps come up with a workable plan to interrupt the negative thoughts really helps.

And I do not know if this will help or not because our brains latch on to strange things to obsess over but. I have lived in several countries and yes, I have gotten food poisoning and it sucked but I lived, and so did you and that is the part that maters. The what if's and could have's will drive you crazy.