Lactococcus lactis is a Gram-positive bacteria used extensively in the production of buttermilk and cheese. L. lactis are cocci that group in pairs and short chains, and depending on growth conditions appears ovoid with typically 0.5 - 1.5 �m in length. L. lactis do not produce spores (non-sporulating) and are not motile (non-motile). Cultured in the laboratory, L. lactis colonies appear bright orange on nutrient agar. They have a homo-fermentative metabolism and have been reported to produce exclusively L(+) lactic acid. However, reported that D(-) lactic acid can be produced when cultured at low pH. The capability to produce lactic acid is one of the reasons why Lactococcus lactis is one of the most important micro-organisms involved in the dairy industry.