This taste keynote by Stuart Firestein attempts to explain why certain foods taste good, while other foods taste bad. His explanation is defined from a biological and cultural standpoint and uses the theory of nature versus nurture.
Stuart believes that taste is an innate and learned thing. For instance, some foods disgust us in a deep way that is built into a being, while other foods like vegetables we learn to find good or bad. Concerning culture, food is sometimes used as punishment and rewards, so this affects our taste. Also, different cultures are offended or disgusted by certain foods while some feature that dish as a staple.
He concludes his taste keynote by saying that for the most part this answer is still unknown and is more than just a scientific answer.