Download or read book Lactic Acid Bacteria written by Wilhelm H. Holzapfel and published by John Wiley & Sons. This book was released on 2014-04-29 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lactic Acid Bacteria Biodiversity and Taxonomy Lactic Acid Bacteria Biodiversity and Taxonomy Edited by Wilhelm H. Holzapfel and Brian J.B. Wood The lactic acid bacteria (LAB) are a group of related microorganisms that are enormously important in the food and beverage industries. Generally regarded as safe for human consumption (and, in the case of probiotics, positively beneficial to human health), the LAB have been used for centuries, and continue to be used worldwide on an industrial scale, in food fermentation processes, including yoghurt, cheeses, fermented meats and vegetables, where they ferment carbohydrates in the foods, producing lactic acid and creating an environment unsuitable for the survival of food spoilage organisms and pathogens. The shelf life of the product is thereby extended, but of course these foods are also enjoyed around the world for their organoleptic qualities. They are also important to the brewing and winemaking industries, where they are often undesirable intruders but can in specific cases have desirable benefits. The LAB are also used in producing silage and other agricultural animal feeds. Clinically, they can improve the digestive health of young animals, and also have human medical applications. This book provides a much-needed and comprehensive account of the current knowledge of the LAB, covering the taxonomy and relevant biochemistry, physiology and molecular biology of these scientifically and commercially important microorganisms. It is directed to bringing together the current understanding concerning the organisms’ remarkable diversity within a seemingly rather constrained compass. The genera now identified as proper members of the LAB are treated in dedicated chapters, and the species properly recognized as members of each genus are listed with detailed descriptions of their principal characteristics. Each genus and species is described using a standardized format, and the relative importance of each species in food, agricultural and medical applications is assessed. In addition, certain other bacterial groups (such as Bifidobacterium) often associated with the LAB are given in-depth coverage. The book will also contribute to a better understanding and appreciation of the role of LA B in the various ecosystems and ecological niches that they occupy. In summary, this volume gathers together information designed to enable the organisms’ fullest industrial, nutritional and medical applications. Lactic Acid Bacteria: Biodiversity and Taxonomy is an essential reference for research scientists, biochemists and microbiologists working in the food and fermentation industries and in research institutions. Advanced students of food science and technology will also find it an indispensable guide to the subject. Also available from Wiley Blackwell The Chemistry of Food Jan Velisek ISBN 978-1-118-38384-1 Progress in Food Preservation Edited by Rajeev Bhat, Abd Karim Alias and Gopinadham Paliyath ISBN 978-0-470-65585-6

Download or read book The Effect of Lactic Streptococci on Growth of Lactobacillus Casei written by Lester Elmer Baribo and published by . This book was released on 1949 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applications of Biotechnology in Traditional Fermented Foods written by National Research Council and published by National Academies Press. This book was released on 1992-02-01 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: In developing countries, traditional fermentation serves many purposes. It can improve the taste of an otherwise bland food, enhance the digestibility of a food that is difficult to assimilate, preserve food from degradation by noxious organisms, and increase nutritional value through the synthesis of essential amino acids and vitamins. Although "fermented food" has a vaguely distasteful ring, bread, wine, cheese, and yogurt are all familiar fermented foods. Less familiar are gari, ogi, idli, ugba, and other relatively unstudied but important foods in some African and Asian countries. This book reports on current research to improve the safety and nutrition of these foods through an elucidation of the microorganisms and mechanisms involved in their production. Also included are recommendations for needed research.

Download or read book The Lactic Acid Fermentation of the Streptococci written by Paul Albert Smith and published by . This book was released on 1941 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Growth and Enzymatic Activities of Some Mutant Strains of Lactic Streptococci written by Kamal Mohamed Kamaly and published by . This book was released on 1988 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Genetics and Biotechnology of Lactic Acid Bacteria written by Michael J. Gasson and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: A prime reference volume for geneticists, food technologists and biotechnologists in the academic and industrial sectors. Fermentations with lactic acid bacteria determine important qualities such as taste, shelf-life, and food values. New methods of food production require fast and reliable manufacture, which has led to a dramatic surge of interest in the genetic, microbiological and biochemical properties of lactic acid bacteria.

Download or read book Genetic Homology and Exchange in Lactic Acid Streptococci written by Martin Dean Knittel and published by . This book was released on 1965 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dairy industry relies primarily on consistent acid production by the lactic streptococci for the manufacture of certain cheeses and fermented dairy products. Variation in these cultures due to genetic exchange has not been thoroughly investigated. This study was undertaken to determine if genetic homology exists within the lactic group, and if genetic exchange by transformation could be demonstrated. Thermal denaturation curves of deoxyribonucleic acid isolated from several strains of Streptococcus lactis, Streptococcus cremoris and Streptococcus diacetilactis showed average mean Tm values of 84.1°C, 84.4°C and 83.7°C, respectively. These values corresponded to guanine plus cytosine percentages of 36.1, 36.8 and 35.1 for the three species. Tm values determined, for comparitive purposes, for species of streptococci belonging to the pyogenic, viridans and enterococcus groups revealed values comparable to those found for the lactic streptococci. The values ranged from 84.0°C for Streptococcus agalactiae to 86.2°C for Streptococcus salivarios, but were clustered around 84.0°C. On the assumption that the molecular distribution of bases within the DNA might be gaussian, normal probability graph paper was used to determine the Tm value, which was the 50 percent point. Comparison of this method with the usual graphical method of determining the Tm value showed that nearly identical results could be obtained. Results from the probability graph paper indicated that the distribution curves derived from thermal denaturation data for some samples were skewed to the left at the lower temperatures of melting. It was found that the skewed portion of the distribution curve could be resolved into two normal distribution curves that overlapped one another; the skewed portion formed a smaller distribution at the lower temperatures. Cesium chloride density gradient factionation of DNA from strains showing skewed distribution curves indicated that a fraction could be separated from the main portion of the DNA. The smaller portion corresponded to a fraction of lower density, the presence of which had been predicted from the distribution curves. A transformation system for S. diacetilactis 18-16 was established, using streptomycin resistance as the marker. The frequency of transformation was low, but the time of appearance of transformants occurred consistently within three to five hours of incubation in the competency medium. At 21°C, the time of appearance of transformants was delayed for five hours; the number of transformants then rose slowly until the experiment was terminated. At 30°C the number reached a maximum at the five-hour interval, and then declined to the end of the experiment. The frequency of transformation was increased by concentrating the cells. Filtration of the samples before exposure to the donor DNA proved to be a more efficient method of cell concentration than centrifugation. The time of maximum expression of the incorporated streptomycin- resistance marker was found to be eight hours at 30°C. The transfer of mannitol utilization by transformation to a mannitol mutant of S. diacetilactis 18-16 was determined qualitatively, and the time of appearance of transformants corresponded to that found for the streptomycin-resistance marker. Minimum methylene blue adsorption by competent cultures occurred at four hours of incubation. This interval corresponded to the midpoint of the range of time at which transformants were detected in transformation experiments.

Download or read book Lysogeny in the Lactic Streptococci written by Fone-Mao Wu and published by . This book was released on 1988 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Growth Requirements of Lactic Streptococcl Differences Within the Group written by G. J. E. Hunter and published by . This book was released on 1949* with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lysogeny in Lactic Streptococci written by Kathleen Ann Meister and published by . This book was released on 1979 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metabolism of Low Concentrations of Glucose and Citrate by Lactic Streptococci written by William Vernon Brown and published by . This book was released on 1976 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bacteriocins of Lactic Acid Bacteria written by Luc De Vuyst and published by Springer. This book was released on 2012-12-06 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: As antibacterial compounds, bacteriocins have always lived in the shadow of those medically important, efficient and often broad-spectrum low-molecular mass antimicrobials, well known even to laypeople as antibiotics. This is despite the fact that bacteriocins were discovered as early as 1928, a year before the penicillin saga started. Bacteriocins are antimicrobial proteins or oligopeptides, displaying a much narrower activity spectrum than antibiotics; they are mainly active against bacterial strains taxonomically closely related to the producer strain, which is usually immune to its own bacteriocin. They form a heterogenous group with regard to the taxonomy of the producing bacterial strains, mode of action, inhibitory spectrum and protein structure and composition. Best known are the colicins and microcins produced by Enterobacteriaceae. Many other Gram-negative as well as Gram-positive bacteria have now been found to produce bacteriocins. In the last decade renewed interest has focused on the bacteriocins from lactic acid bacteria, which are industrially and agriculturally very important. Some of these compounds are even active against food spoilage bacteria and endospore formers and also against certain clinically important (food-borne) pathogens. Recently, bacteriocins from lactic acid bacteria have been studied intensively from every possible scientific angle: microbiology, biochemistry, molecular biology and food technology. Intelligent screening is going on to find novel compounds with unexpected properties, just as has happened (and is still happening) with the antibiotics. Knowledge, especially about bacteriocins from lactic acid bacteria, is accumulating very rapidly.

Download or read book The Peptidase System of Lactic Streptococci Its Cellular Location and Its Activity on Hydrolysis Products from Rennet Curd written by Ronald Herbert Schmidt and published by . This book was released on 1974 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Heat Inactivation of Bacteriophages Specific for Lactic Streptococci written by Massis Yeterian and published by . This book was released on 1967 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Genetics of Lactic Acid Bacteria written by Brian J.B. Wood and published by Springer Science & Business Media. This book was released on 2003-09-30 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with an introduction to relevant genetic techniques, chapters cover all major groups of LAB, including the Bifidobacteria; plasmid biology, gene transfer, phage, and sugar metabolism; gene expression of various LAB; applications for genetically engineered LAB, including the emerging field of medical applications; and the legal and consumer issues that arise from such applications. This resource will set the benchmark for the state of knowledge of LAB genetics and should be of value to food scientists and other researchers working with LAB in its present and future capacities. Professionals using lactic acid bacteria (LAB) for research and/or as working organisms, whether in food and dairy fermentations or in the exciting new field of clinical delivery agents, will find this book invaluable. In addition, professors teaching under- and post-graduates in microbiology, and postgraduate research students will also find this an essential reference work.

Download or read book On the Origin of Bacteriophages for the Lactic Streptococci written by Hugh Robinson Whitehead and published by . This book was released on 1941* with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Ecological Study of the Lactic Streptococci written by Paul Christian Radich and published by . This book was released on 1968 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an attempt to determine the natural habitat of Streptococcus lactis, Streptococcus cremoris, and Streptococcus diacetilactis 27 different species of vegetables, 18 species of fruits and many individual cow raw milk samples were examined. S. lactis was found to occur on potatoes, corn, cucumbers, peas, beans, and cantaloupe. In each case the organism was isolated in low numbers. The remaining 21 vegetables failed to yield any of the organisms sought. No lactic streptococci were isolated from any of the fruits examined. Almost all of the organisms isolated from fruits were able to grow at 45°C., thus precluding their identification as lactic streptococci. Those which did not grow at 45°C. had a cell morphology which excluded them from the lactic streptococcus group. Individual cow milk samples provided S. lactis, S. cremoris, and S. diacetilactis isolates. If the milk samples were kept at 21° C. for two to three days before plating, good yields of streptococci could be obtained, especially S. lactis. However, if the milk samples were immediately plated upon receiving them, lower numbers were found. The biochemical, cultural, and morphological characteristics of both the plant and milk isolates agreed in every detail with the standard descriptions of the lactic streptococci available in the recent literature; growth was found to take place at 10°C. and at 40°C, but not at 45°C. Litmus milk was acidified and completely reduced before curdling. No gas production was observed in the coagulated milk. Acid producing abilities of those cultures isolated from plants were somewhat higher than those cultures isolated from milk. Also, there was a wider range in acid producing abilities of the milk isolates than those cultures obtained from plant material. Most of the cultures which were isolated from plants produced concentrations of less than 50 ppm of total carbonyl compounds expressed as pyruvic acid. This also was true for those cultures obtained from milk. However a wide range (16 to 76 ppm) in the ability to produce carbonyl compounds was seen in both cases. The isolation of S. lactis from several different plant sources confirmed the belief that plants are the natural habitat for this bacterium. Failure to isolate S. cremoris from plant material suggests that this species may be a variant of S. lactis with milk as its natural habitat.