If you do a search of phobias on google, you will find that some people do have bananaphobia. But the question about if it is medically recognised, I do not think there is a specific term for it. Nevertheless, I do think that psychiatrists, psychologists will be willing to consider the bananaphobia condition if it seriously affects one's lifestyle. Cognitive behavourial therapy or anti-anxiety medicationmight be used if it is particularly a serious and debilitating conditon I believe. But in these circumstances its best to consult a professional, and in case it isnot very serious, I do not think you ought to worry about it because there are loads of conditions for which even medicine has no answers for.