African Journal of Microbiology Research Vol. 6(5), pp. 859-866, 9 February, 2012 Available online at http://www.academicjournals.org/AJMR DOI: 10.5897/AJMR11.031 ISSN 1996-0808 ©2012 Academic Journals Review Streptococcus thermophilus bacteriocin, from production to their application: An overview Shadab Gul 1 , Tariq Masud 1 *, Shabana Maqsood 2 , Asia Latif 1 , Imran Irshad and Irfan ul Haque 3 1 Department of Food Technology, Pir Mehr Ali Shah Arid Agriculture University Rawalpindi Pakistan. 2 Department of Microbiology, Quaid-i-Azam University Islamabad, Pakistan. 3 Department of Plant Pathology, Pir Mehr Ali Shah Arid Agriculture University Rawalpindi Pakistan. Accepted 15 December, 2011 Streptococcus thermophilus have potent antimicrobial activities toward closely related bacteria and undesirable harmful microorganisms. Certain S. thermophilus strains are able to produce substances that compete and prevent pathogenic bacteria from adhering to the receptors on epithelial cells of intestinal surfaces. The potential probiotic effects of S. thermophilus are well known in the human ecosystem and their production of antimicrobial peptides can contribute to elucidate the precise mechanisms by which S. thermophilus can dominate the intestinal microbiota and achieve their probiotic function. This paper presents a review of the antimicrobial proteinaceous compounds produced by various streptococcus strains, the attempts made to purify them, their characterization and useful applications. Key words: Streptococcus thermophilus, bacteriocin. INTRODUCTION Streptococcus thermophilus is commonly used as starter culture for the preparation of different milk products and also considered as most important starter for industry after Lactococcus lactis (Hols et al., 2005). Traditionally, It is used for making yoghurt and different varieties of cheeses, for example, hard-cooked cheeses (Emmental, Gruyère, Parmigiano and Grana-types, etc.), Mozzarella and Cheddar cheeses. Being thermophillic in nature, it plays a vital role for different production processes used for the preparation of dairy products. It may be used alone or in combination with other lactobacilli and mesophillic starter culture used for cheese making, whereas in case of yoghurt it is always used with Lactobacillus delbrueckii sp. bulgaricus due to their symbiotic relationship (Auclair and Accolas, 1983). In milk fermentation, the role of S. thermophilus is attributed to the rapid rate of lactic acid production from lactose that result in reduction of pH and production of secondary *Corresponding author. E-mail: drmasud_tariq@hotmail.com. metabolites. Together, S. thermophilus, S. salivarius and S. vestibularis form the salivarius group of viridans streptococci (Facklam, 2002). S. thermophilus is the only streptococcal species that is present in dairy products therefore regarded as GRAS. Whereas, other viridans streptococci showed commensals relationship in the oral cavity, gastrointestinal and genital tracts of mammals. Similarly, S. salivarius and S. vestibularis have been reported to isolate from the human oral cavity and are responsible for human infections. Some cases of meningitis, endocarditis and bacteraemia are reported due to oral streptococci (Doyuk et al., 2002; Idigoras et al., 2001; Ruoff et al., 1989). The genomes of these three S. thermophilus strains were sequenced recently which showed the inactivation or absence of virulence related genes which is attributing of the pathogenic streptococci. The interest in the research of antimicrobial peptides including bacteriocins and bacteriocin-like compounds is increasing day by day because of their antimicrobial potential that improves the safety of different food products (Yildirim et al., 1999). The combinations of