According to the United Nations Food Agriculture Organization (FAO) and the World Health Organization (WHO), probiotics are “live microorganisms, which when administered in adequate amounts, confer a health benefit on the host.” Traditionally, these “friendly bacteria” were found in fermented foods such as yogurt and cultured milk, but can now be found as an added ingredient in milk and cheese as well. Some strains of probiotics have been associated with digestive health, while others may benefit the immune system.