Traditional (classical) biotechnology includes fermentation, breeding, and the production of antibiotics and vaccines. Fermentation involves using microbes like yeast and bacteria to produce foods and beverages through anaerobic respiration, including beer, wine, cheese, bread and yogurt. Breeding techniques like inbreeding and crossbreeding were used to selectively develop plant and animal varieties with desirable traits. Early methods discovered antibiotics produced by microorganisms and used vaccines containing weakened or killed pathogens to trigger immune responses without causing illness.