Two foods that bacteria help make are yogurt and Swiss cheese. Yogurt is made from milk innoculated with "good" or probiotic bacteria, such as Lactobacillus delbrueckii. Swiss cheese is produced from Streptococcus salivarius, Lactobacillus, and Propionibacterium.
The bacteria used for yogurt support healthy digestion by easing conditions such as lactose intolerance and by reducing the damage done by other bacteria such as H. pylori.
In the production of Swiss, or Emmental, cheese, Propionibacteria eat the lactic acid made by other bacteria. This causes carbon dioxide to form the holes or "eyes" of the cheese, while the nutty and sweet flavor comes from the acetate and propionic acid.