I think you should go and by no means let the OCD win. Your post reads like lots of different issues flood your mind. The main common thing about them seems to be the core OCD problem: need for control. Well, we cannot control everything in our lives and traveling is kinda (possibly) unpredictable thing... If we go through your worries one by one:
1. Dirty center and bugs. Since the place hosts business meetings chances of that are pretty slim, in my opinion. And what would be the worst thing that could happen if the place WAS dirty? You'd feel uncomfortable? (I'm sure you can handle uncomfort.) You'd catch a disease? (Chances of that are almost nonexistent.) Any more ideas? All in all this issue doesn't represent a catastrophy but uncomfort.
2. Dogs& allergies. Since there was no problem for decades, the chances of you developing one are really low. And what would be the worst case scenario? You'd have to take your meds or move to another location. That is inconvenient, yes, but it's not a catastrophy.
3. Afraid of sleeping in a strange bed. Why? What could happen? You'd get dirty? See point 1.
4. Food. This doesn't seem to be only the traveling issue. Perhaps you can bring your own food and think about possibly changing the habit while you're back home, in a 'safe' environment. Maybe, if you feel courageous, you could have a small bite of something not prepaired by you on each trip just to survive a tiny exposure? Might give you anxiety, which is uncomfortable, but doing it could boost your self esteem.
I know I make it seem like it's all simple but well...it kinda is. You just need to be ready to confront your fears and don't let them win. Having OCD issues myself, changing my catastrophic thinking into realistic one PLUS small steps exposure seem to do the trick and take the edge off the matters.
Wishing you safe and pleasant trips