 Additionally, exogenous bacteria can enter a secondary host through an intermediate host such as insects and parasites.Exogenous bacteria can also enter an enclosed ecosystem via ingestion of contaminated food.Food-borne diseases such as "Salmonella" poisoning are transmitted by food not properly cooked or by individuals infected with the pathogen.One of the most common food-borne illnesses, "Salmonella" poisoning is caused by ingestion of unsanitary conditions during food preparation.