I'm also allergic to apples, deathly so, and apples are used in a ton of things you would never expect. I recently developed a gluten intolerance.
So I just gave up and have gone vegetarian. I still eat eggs, milk and cheese, but no meat at this time. I feel pretty good.
And yeah, it was very dangers when traveling. Often, I could not express my allergies in another language, and that was risky as hell.