Streptococcus thermophilus

Streptococcus thermophilus also known as Streptococcus salivarius subsp. thermophilus is a gram-positive bacterium, and a fermentative facultative anaerobe, of the viridans group. It tests negative for cytochrome, oxidase, and catalase, and positive for alpha-hemolytic activity. It is non-motile and does not form endospores. S. thermophilus is fimbriated. It has an optimal growth temperature range of 35 - 42 °C while L. bulgaricus has an optimal range of 43 - 46 °C. It is also classified as a lactic acid bacterium. S. thermophilus is found in fermented milk products, and is generally used in the production of yogurt, alongside Lactobacillus delbrueckii subsp. bulgaricus. The two species are synergistic, and S. thermophilus probably provides L. d. bulgaricus with folic acid and formic acid which it uses for purine synthesis. At least 26 strains of S. thermophilis have been identified and had their genomes sequenced. S. thermophilus is one of the most widely used bacteria in the dairy industry. USDA statistics from 1998 showed that more than 1.02 billion kilograms of mozzarella cheese and 621 million kilograms of yogurt were produced from S. thermophilus. Although its genus, Streptococcus, includes some pathogenic species, food industries consider S. thermophilus a safer bacterium than many other Streptococcus species. In fact, yogurt and cheese that contain live cultures of S. thermophilus are thought to be beneficial to health. Live cultures of S. thermophilus make it easier for people who are lactose intolerant to digest dairy products. The bacteria break down lactose, the sugar in milk, that lactose-intolerant people find difficult to digest. As early as the 1900s, S. thermophilus has been used to make yogurt. Its purpose is to turn lactose, the sugar in milk, into lactic acid. The increase in lactic acid turns milk into the gel-like structure characteristic of yogurt. 'Streptococcus' derives from a Greek term meaning 'twisted berry' and refers to the way the bacterium is grouped in chains that resemble a string of beads. 'Thermophilus' derives from the Greek thermē, meaning 'heat'. It refers to an organism's ability to thrive at high temperatures. The genus Streptococcus includes several pathogenic species, such as S. pneumoniae and S. pyogenes, but food industries consider S. thermophilus non-pathogenic. S. thermophilus is believed to have developed separately from pathogenic Streptococcus species for at least 3000 years. Research teams have sequenced the genome of two strains of S. thermophilus, CNRZ1066 and LMG13811, and stated that the bacteria are not dangerous. S. thermophilus strain Orla-Jensen 1919 is a constituent in VSL#3. This standardized formulation of live bacteria may be used in combination with conventional therapies to treat ulcerative colitis. The use of the S. thermophilus-containing VSL#3 may reduce inflammation in mice.