There are some bacteria in the gut that produce hydrogen sulfide gas. This gas has a smell
of rotten eggs
. Most of this gas comes from sulfites a person consumes, which is a part of all preservatives. Sulfites are present in all juices, molasses, yellow dye in ready made food stuffs, and red wine. Sulfites are present in lesser amounts in mashed potatoes made from dry powder, pickles, tinned shrimp, cookies, crackers, and readymade pie dough.