Yeah, it would be interesting to see what the Florida Evidence Code has to say on this but that sounds as though your saying the Jury would be smelling the odour to determine that the odour was more akin to a banana rather than a dead human body (to wit: Caylee). Which is problematic:
a.) I am unsure if the Jury should be making a determination that the odour is decomposition of a banana. On what basis would the do so? What experience do they have?
b.) Similarly they certainly shouldn't be making a determinination that the odour is a decomposition of a human body. Considerations, ditto.
c.) They shouldn't be entering into a comparative analysis.