In some cases, eating mold can cause an allergic reaction, respiratory problems and illness, according to United States Department of Agriculture. Molds that cause illness are those that produce mycotoxins, poisonous substances that can grow on foods when stored under certain conditions, including in the refrigerator.
In other cases, molds are eaten on purpose and do not cause problems, such as in the case of many cheeses that contain surface or internal molds, including Brie, Camembert, blue and Gorgonzola cheeses, according to the USDA. If mold is found on other foods where it should not be, discarding the food is best to avoid adverse reactions and sickness. Sniffing moldy foods is not advisable either as this can disperse spores and cause respiratory problems.