Dear Barbara: Some casual restaurants I go to have the ketchup bottle on the table all day. Does this mean that ketchup doesn’t have to be refrigerated? I would also like to know if mayonnaise has to be refrigerated if it is purchased at a store and not homemade. — Gwen from Lodi
Dear Gwen: Most all ketchup says to refrigerate after opening. Some of this is to hold the quality of the product.