I considered putting this question into the Travel stackexchange but this issue feels like it's more to do with interpersonal skills and communication than actually travelling. I'm happy for it to be moved if necessary.
To put it briefly, I have a particular, very uncommon phobia which happens to overlap with a food that's considered a delicacy in many countries. I've found myself in a number of situations where I have to turn down high quality, expensive food because I simply can't bring myself to put it in my mouth, and I'm worried that this comes off as rude.
I'm very adventurous when it comes to new foods and more than happy to try something new, but this food is the one exception for me. Unfortunately it's common enough that it comes up from time to time, but not so common that I can simply avoid any restaurant that might serve it.
Ordinarily it would be simple enough to explain that it's due to a phobia I have, but this is a much bigger issue when travelling in countries where my hosts might have limited, if any, English-speaking skills, and come from a culture that might be less sensitive when it comes to mental health issues. In these cases my hosts may end up pressuring me to try this food, because I 'might like it', but though I hate to, I still have to refuse.
This happened last time I travelled, when my hosts invited me out for a big family dinner with about 10 other people, and I had to turn down the feature dish. The people around me seemed quite confused and perhaps a little hurt that I didn't want to partake. I'm travelling again soon and, being a bit of a foodie, have plans to eat at a number of high-end restaurants, but I'm worried about this coming up and that I'll offend the chef.
I've tried steps to manage my phobia over the last few years and have come a long way. It's a lot milder than it used to be but eating the things that trigger it is still not something I can do, and may never be. I'm worried that if I did just suck it up and try it I would end up vomiting and causing a significantly worse situation.
Obviously learning the local word for 'phobia' would be a start, but I'm not sure how effective this is. Is there a universally-applicable way that I can tactfully refuse this food if it's put in front of me without seeming rude?