Food microbiology protocols

Psychrotrophic Microorganisms: Agar Plate Methods, Homogenization, and Dilutions Anavella Gaitán Herrera ........................................................................ 3 2 Biochemical Identification of Most Frequently Encountered Bacteria That Cause Food Spoilage Maria Luisa Genta and Humberto Heluane ...................................... 11 3 Mesophilic Aerobic Microorganisms Anavella Gaitán Herrera ...................................................................... 25 4 Yeasts and Molds Anavella Gaitán Herrera ...................................................................... 27 5 Coliforms Anavella Gaitán Herrera ...................................................................... 29 6 Genetic Analysis of Food Spoilage Yeasts Stephen A. James, Matthew D. Collins, and Ian N. Roberts .......... 37 PART II PATHOGENS 7 Conductimetric Method for Evaluating Inhibition of Listeria monocytogenes Graciela Font de Valdez, Graciela Lorca, and María Pía de Taranto ....................................................................... 55 8 Molecular Detection of Enterohemorrhagic Escherichia coli O157:H7 and Its Toxins in Beef Kasthuri J. Venkateswaran ................................................................. 61 9 Detection of Listeria monocytogenes by the Nucleic Acid Sequence- Based AmplificationTechnique Burton W. Blais and Geoff Turner ..................................................... 67 10 Detection of Escherichia coli O157:H7 by Immunomagnetic Separation and Multiplex Polymerase Chain Reaction vii Ian G. Wilson ........................................................................................ 85 viii Contents 11 Detection of Campylobacter jejuni and Thermophilic Campylobacter spp. from Foods by Polymerase Chain Reaction Haiyan Wang, Lai-King Ng, and Jeff M. Farber ................................ 95 12 Magnetic Capture Hybridization Polymerase Chain Reaction Jinru Chen and Mansel W. Griffiths ................................................ 107 13 Enterococci Anavella Gaitán Herrera .................................................................... 111 14 Salmonella Anavella Gaitán Herrera .................................................................... 113 15 Campylobacter Anavella Gaitán Herrera .................................................................... 119 16 Listeria monocytogenes Anavella Gaitán Herrera .................................................................... 125 PART III FERMENTED FOODS 17 Methods for Plasmid and Genomic DNA Isolation from Lactobacilli M. Andrea Azcárate-Peril and Raúl R. Raya ................................... 135 18 Methods for the Detection and Concentration of Bacteriocins Produced by Lactic Acid Bacteria Sergio A. Cuozzo, Fernando J. M. Sesma, Aída A. Pesce de R. Holgado, and Raúl R. Raya ....................... 141 19 Meat Protein Degradation by Tissue and Lactic Acid Bacteria Enzymes Silvina Fadda, Graciela Vignolo, and Guillermo Oliver ................ 147 20 Maintenance of Lactic Acid Bacteria Graciela Font de Valdez .................................................................... 163 21 Probiotic Properties of Lactobacilli: Cholesterol Reduction and Bile Salt Hydrolase Activity Graciela Font de Valdez and María Pía de Taranto ....................... 173 22 Identification of Exopolysaccharide-Producing Lactic Acid Bacteria: A Method for the Isolation of Polysaccharides in Milk Cultures Fernanda Mozzi, María Inés Torino, and Graciela Font de Valdez................................................................ 183 23 Differentiation of Lactobacilli Strains by Electrophoretic Protein Profiles Graciela Savoy de Giori, Elvira María Hébert, and Raúl R. Raya ................................................................................... 191 24 Methods to Determine Proteolytic Activity of Lactic Acid Bacteria Graciela Savoy de Giori and Elvira María Hébert .......................... 197 25 Methods for Isolation and Titration of Bacteriophages from Lactobacillus Lucía Auad and Raúl R. Raya .......................................................... 203 26 Identification of Yeasts Present in Sour Fermented Foods and Fodders Wouter J. Middelhoven ..................................................................... 209 PART IV ORGANISMS IN THE MANUFACTURE OF OTHER FOODS AND BEVERAGES 27 Protein Hydrolysis: Isolation and Characterization of Microbial Proteases Marcela A. Ferrero ............................................................................. 227 28 Production of Polyols by Osmotolerant Yeasts Lucía I. C. de Figueroa and María E. Lucca.................................... 233 29 Identification of Yeasts from the Grape/Must/Wine System Peter Raspor, Sonja Smole Mozina, and Neza Cadez ................... 243 30 Carotenogenic Microorganisms: A Product-Based Biochemical Characterization José Domingos Fontana ................................................................... 259 31 Genetic and Chromosomal Stability of Wine Yeasts Matthias Sipiczki, Ida Miklos, Leonora Leveleki, and Zsuzsa Antunovics ........................................................................ 273 32 Prediction of Prefermentation Nutritional Status of Grape Juice: The Formol Method Barry H. Gump, Bruce W. Zoecklein, and Kenneth C. Fugelsang .................................................................. 283 33 Enological Characteristics of Yeasts Fabio Vasquez, Lucía I. C. de Figueroa, and Maria Eugenia Toro ....................................................................... 297 34 Utilization of Native Cassava Starch by Yeasts Lucía I. C. de Figueroa, Laura Rubenstein, and Claudio González........................................................................... 307 PART V METHODS AND EQUIPMENT 35 Reactor Configuration for Continuous Fermentation in Immobilized Systems: Application to Lactate Production José Manuel Bruno-Bárcena, Alicia L. Ragout de Spencer, Pedro R. Córdoba, and Faustino Siñeriz .................................... 321 Contents ix x Contents 36 Molecular Characterization of Yeast Strains by Mitochondrial DNA Restriction Analysis Maria Teresa Fernández-Espinar, Amparo Querol, and Daniel Ramón................................................................................. 329 37 Selection of Yeast Hybrids Obtained by Protoplast Fusion and Mating, by Differential Staining, and by Flow Cytometry Tohoru Katsuragi ............................................................................... 335 38 Selection of Hybrids by Differential Staining and Micromanipulation Tohoru Katsuragi ............................................................................... 341 39 Flotation Assay in Small Volumes of Yeast Cultures Sandro Rogério de Sousa, Maristela Freitas Sanches Peres, and Cecilia Laluce ......................................................................... 349 40 Obtaining Strains of Saccharomyces Tolerant to High Temperatures and Ethanol Maristela Freitas Sanches Peres, Sandro Rogério de Sousa, and Cecilia Laluce ......................................................................... 355 41 Multilocus Enzyme Electrophoresis Timothy Stanley and Ian G. Wilson ................................................. 369 42 Bacteriocin Production Process by a Mixed Culture System Suteaki Shioya and Hiroshi Shimizu .............................................. 395 PART VI REVIEWS 43 Nutritional Status of Grape Juice Bruce W. Zoecklein, Barry H. Gump, and Kenneth C. Fugelsang .................................................................. 415 44 Problems with the Polymerase Chain Reaction: Inhibition, Facilitation, and Potential Errors in Molecular Methods Ian G. Wilson ...................................................................................... 427 45 Problems with Genetically Modified Foods José Manuel Bruno-Bárcena, M. Andrea Azcarate-Peril, and Faustino Siñeriz ............................................................................. 481 Index ......................................................................................................... 485