What are the examples of superstitious beliefs about food with its scientific explanation?

Answer 1

The old advisory that did not allow the consumption of pork in hot climates. This was before refrigeration, meat spoiled faster in hot climates, food poisoning was thought to come from "evil spirits," hence the superstition.

It was once believed tomatoes were poisonous, this could be explained by the fact tomatoes are a member of the "nightshade" family. Nightshade is poisonous, so thinking tomatoes could kill you made a fair amount of sense. Today we know the plant is not good for us, but the fruit is edible.