Leuconostoc mesenteroides SJRP55: A Bacteriocinogenic Strain Isolated from Brazilian Water Buffalo Mozzarella Cheese

The production of bacteriocins by Leuconostoc mesenteroides represents an important opportunity for exploration of their potential use for industrial purpose. The antimicrobial compounds produced by L. mesenteroides subsp. mesenteroides SJRP55 strain were characterized and purified. Cell-free supernatant of Leuc. mesenteroides subsp. mesenteroides SJRP55 produced antibacterial compounds against Listeria spp. strains and not inhibiting against Lactobacillus spp. The antimicrobial substances were stable at high temperatures (100 C for 2 h and 121 C for 20 min) and low pH (pH 2–4) values, but sensitive to proteolytic enzymes and resistant to aamylase, lipase and catalase enzymes. The optimal temperature for active peptides production was 25 C. The antimicrobial compounds were purified by ammonium sulfate precipitation, affinity column and reverse-phase chromatography. Mass spectrometry and amino acids analyses showed that the bacteriocins were identical to mesentericin Y105 and B105. The producer strain’s DNA analysis revealed presence of open reading frames possibly coding for virulence factors, such as enterococcal surface protein (esp), collagen adhesion (ace) and intrinsic vancomycin resistance (vanA); however, biogenic amines encoding genes were not observed. Leuc. mesenteroides subsp. mesenteroides SJRP55 is a promising biopreservative culture in fermented milk, and the purified bacteriocins can also be applied in food preservation.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Engenharia e Tecnologia de Alimentos, Instituto de Biociências Letras e Ciências Exatas de São José do Rio Preto, Sao Jose do Rio Preto, R. Cristóvão Colombo, 2265, Jardim Nazareth, CEP 15054-000, SP, BrasilUniversidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Engenharia e Tecnologia de Alimentos, Instituto de Biociências Letras e Ciências Exatas de São José do Rio PretoFAPESP: 2010/09302-1FAPESP: 2011/11922-

Microbial metabolites as biological control agents in food safety

Ensuring food safety and at the same time meeting such demands for retention of nutrition and quality attributes have resulted in increased interest in alternative preservation techniques for inactivating microorganisms and enzymes in foods. This increasing demand has opened new dimensions for the use of natural preservatives derived from plants, animals, or microflora. Extensive research has investigated the potential application of natural antimicrobial agents in food preservation. Especially the significance and use of microbes as producers of antimicrobial metabolites has increased significantly during the last decades. Reported studies have demonstrated that microbial metabolites from microorganisms exhibited a great numbers of diverse and versatile biological effects about antimicrobial activities. These microorganisms produce many compounds that are active against other microorganisms, which can be harnessed to inhibit the growth of potential spoilage or pathogenic microorganisms. These include fermentation end products (metabolites) such as organic acids, hydrogen peroxide, and diacetyl, biofilm, exopolysaccharides in addition to bacteriocins and other antagonistic compounds such as reuterin. Up to now, antimicrobial metabolites from lactic acid bacteria (such as nisin) have been mostly used in food preservation. In addition to lactic acid bacteria, some yeast, mold, and another bacteria species as well as some pathogenic bacteria can produce antimicrobial metabolites. Antimicrobial metabolites present in foods can extend the shelf life of unprocessed or processed foods by reducing the microbial growth rate or viability. This offers a new knowledge-based approach to the exploitation of bacteria for food production, from metabolic engineering of microorganisms to produce antimicrobials or nutritionals, to the molecular mining of activities as yet unknown but which could benefit food production. In addition, the availability of the genomes of many food pathogenic and spoilage bacteria may open up new possibilities for the design of novel antimicrobials which target essential functions of these problematic bacteria. In this chapter, antimicrobial metabolites from microorganism in food safety as a biocontrol agent reviewed. © 2014, Springer Science+Business Media New York