The use of lactic acid bacteria in food production is perhaps one of the oldest examples of biotechnology. It is probable that fermented milk has been consumed since man started milking animals, possibly as far back as 11,000 years ago. Over the years, numerous fermented foods have been developed, each with its own microbiological flora involved in production. These fermented foods have arisen without microbiological skills or knowledge; only relatively recently have we been able to understand the biological process underlying food fermentation by lactic acid and other bacteria.