New tendencies in Microbiology

Coordinated by:

Université de Bordeaux

Objectives of the course:

  • Teach students the basics in wine microbiology: non-Saccharomyces yeasts, Saccharomyces yeasts, lactic acid bacteria, acetic acid bacteria, diversity and classification, cell structure and metabolism, development in wine, achievement of alcoholic and malolactic fermentations, and modulation of wine quality.  

  • Teach students the recent developments in the knowledge and control of wine yeasts and bacteria: genomics and ecology of species, selection and application of starter cultures, yeasts and bacteria in the context of bioprotection and reduction of sulfites, and methods for identification and monitoring of beneficial and undesirable yeasts and bacteria during winemaking.

  •  Teach students the oenological codex, oenological practices and wine treatments, to Know the technical aids and additives allowed in wines, to be able to control oenological practices and wine treatments (physical, chemical, ...), to understand the mechanisms of action of oenological products, stability and colloidal phenomena involved in the life of wine., to know how to solve the problems of breaking a wine, to know how to use the appropriate shutters for bottling a wine.

  • Teach students about new oenological practices and existing ones taking into account environmental impact / sustainability and consumer health and technological innovations. Teach students the food safety and physiological effects of wine on human health toxicological risks of different types of contaminants and how to reduce the risks and prevent contaminations. 

  • Teach students To identify the risks for workers/consumers and to propose methods to limit them in the context of viticultural practices, processes and treatments.

  • Teach students to be able to constantly adapt the process of transformation of grapes into wine according to the results of microbiological, chemical and sensory analyzes. Being able to use the tools of sensory analysis to judge the intrinsic quality of the wine obtained. Being able to use the tools of sensory analysis to judge its conformity with the desired product.

Content of the course

  • Microbiology (20 hours + 20 hours, Optional 20 hours)

  • Wine Aging (20 hours + 20 hours, Optional 20 hours)

  • Wine safety (20 hours + 20 hours Optional or 20hours Optional)
     

Microbiology

1.Basics in wine microbiology (20h)

 

  • Diversity and classification of wine yeasts and bacteria (2h)

    • Yeasts of grape must and wine

    • Lactic acid bacteria

    • Acetic acid bacteria

  • Structure of the yeast cell (2h)

  • Metabolism of yeasts (4h)

  • Growth of yeasts and kinetics of alcoholic fermentation (4h) 

  • Structure of the bacterial cell (1h)

  • Metabolism of lactic acid bacteria (3h)

  • Growth of lactic acid bacteria and the achievement of malolactic fermentation (2h)

  • Metabolism and growth of acetic acid bacteria (1h)

  • Microbial spoilage in wine (1h)

2. Recent developments in wine microbiology (20h)

 

  • Genomics, diversity, selection, applications (10h)

    •  Genomics and ecology of wine yeasts and bacteria (4h)

      •  Microbial genomics in the era of next-generation sequencing technologies

      •  Genomes of wine yeasts

      •  Genomes of wine bacteria

      •  Biodiversity, biogeography, the ecology of Saccharomyces cerevisiae, Brettanomyces bruxellensis, other non-Saccharomyces yeasts, Oenococcus oeni

    • Selection and application of yeast and bacterial starter cultures (4h)

      • Selection and industrial production of yeasts

      • Selection and industrial production of lactic acid bacteria

      • Strategies for starter inoculation and management of fermentations

    • Bioprotection and reduction of sulfites (2h)

      • ​Microbial populations and risks in no-sulfites wine

      • Microbial cultures and application for bio protection
         

  • Modern methods for identification and monitoring of wine yeasts and bacteria (10h)

    • Monitoring wine yeast and bacteria populations by plate counts and microscopy (2h)

    • Control of implantation of yeast and bacteria starter cultures (2h)

    • Application of quantitative PCR and flow cytometry for monitoring Brettanomyces bruxellensis (2h)

    • Fast identification of yeasts and bacteria by mass spectrometry (2h)

3. Optional: Recent developments in wine microbiology (20h)​

  • Practical Microbiology (20 h) 

  • Laboratory setup and basic microscopy (1h)

  • Laboratory practical (10H)

  • Preparing smears (wet mount and hanging drop, mold slide culture, bacterial smears) (1h)

  • Sterilization of laboratory media and supplies (2h)

  • Media preparation for wine microorganisms (2h)

  • Direct plating (spread plate, pour plate, membrane filtration, and plating) (2h)

  • Isolation of wine yeast and bacteria (aseptic transfer techniques) (2h)

Wine Aging

1. Wine Aging and processes 1 (20h)

  • Management of disolved gases (4h)

    • Role of oxygen and carbon dioxide during the vinification

    • Analytical techniques

    • Inert gas and protection against oxidation and reduction

  • Microbiological stabilization (4h)

    • Filtration process

    • Others process to ensure microbial stabilization

  • Ageing condition (4h)

    • Ageing in oak barrels

    • Impact of oak barrel and alternative product on wine

    • Impact of cork during wine ageing in bottles

  • Colloids / Disorders and Deposit (4h)

    • Wine colloids

    • Colloids properties

    • Mechanism of stability and instability of colloidal solution

    • Formation mechanism of haze and deposit

  • Stabilization Physico-chemical (4h)

    • Fining agent

    • Process to avoid haze and deposit

​2. Wine Ageing and processes 2 (20h)

  • Preservation of wines (4h)

    • Management of oxygen along the vinification

    • Protection against oxidation and reduction

  • Cellar design (4h)

    • Basics of design

    • Importance of the materials

  • Mechanism of stabilization and evolution (4h)

    • Wine color stabilization

    • Formation mechanisms of polymeric pigment

    • Evolution mechanisms of tannins during ageing

    • Modulation of the mouthfeel organoleptic properties during wine ageing

  • Visits with cases example (8h)

3. Optional: Wine microbiology and aging (20h)

  • Microbiology and aging

    • Biochemical Changes During Aging (2)

    • Morphological Changes in Yeast Cells During Aging (2)

    • The Genetics of Autolysis: Autophagy (2)

  • Methods to Accelerate Yeast Autolysis in Wine and Implications for the Production Process (2)

    • Increased Temperature and Addition of Autolysates

    • Genetic Improvements in Yeast

  • Characteristics of Yeasts used in biologically aged Wines

    • Microbiota in the Flor Film (1)

    • Physiological Characteristics of Fermentation and Aging Yeasts (2)

    • Flor Formation (1)

    • Genetic Characteristics of Fermentation and Aging Yeasts (2)

  • Influence of Environmental Factors on the Characteristics of Yeasts Involved in Biological Aging (3)

    • Influence on Mitochondria

    • Influence on Chromosomes

    • Influence on the membrane and Cell Wall

  • Evolution of Cellular Genomes and Yeast Populations in Biologically Aged Wines (2)

  • Genetic Improvement of Wine Yeasts (4)

    • Improving the Characteristics of Fermentation Yeasts

    • Improving the Characteristics of Aging Yeasts

  • Population Dynamics in lactic acid bacteria during wine aging. Influence on wine composition (2)

Wine Safety 

1.Wine Safety (12h)

  • Notion of contaminants (endogenous, exogenous) (1h)

  • Cases Contaminants (10h)

  • Mycotoxins  (e.g. : Ochratoxin A,  …..)

  • Ethyl Carbamate

  • Polycyclic Aromatic Hydrocarbons

  • Biogenic Amines

  • Metals (Lead, Cadmium, Iron, Copper, Ni, Cr, ... ..)

  • Acetaldehyde

  • Materials in contact with wine (Phthalates, Bisphenol A)

  • Allergens: concept of allergy

  • Intolerance and hypersensitivity

  • (SO2, clarification products that may interact and labeling: caseins, lysozyme, plant protein materials, ichthyocollus)

  • Residues of phytosanitary products

  • GMO

  • Solutions to food safety issues concerning wine (1h)

2. Physiological effects of wine consumption:  (8h)

  • Pharmacology and Pharmacokinetics of Alcohol (3h)

  • Metabolism and Alcohol Calories

  • Health Risks Associated with Alcohol Consumption

  • Safety Dose Concept

  • Epidemiological studies and effects on human health (risk of mortality) (5h)

  • Consumption of wine and atherosclerosis (in vitro and in vivo studies)

  • Wine consumption and diabetes (in vitro and in vivo studies)

  • Wine consumption and hypertension (in vitro and in vivo studies)

  • Consumption of wine and cancer (in vitro and in vivo studies)

  • Metabolism and activity of polyphenols

  • Mechanisms of action of phenolic compounds of wine on human health

  • Wine, polyphenols and oxidative stress

3. Optional: Wine quality experience tasting (20 hours)

  • Wines and microbial diversity incidence (white, rose, red wines, sweet wines) (4h)

  • Wines and different ageing types incidence (white, rose, red wines, sweet wines) (4h)

  • Wines and matrix component influence (alcohol, acids and pH, volatile compounds, non volatile compounds) (4h)

  • Organic wines types (white, rose, red wines, sweet wines), quality and risks and new types of wines (4h)

  • Visit of different wineries (Conventional, Organic, etc..) (4h)

4. Optional: Quality Insurance: General considerations regarding The HACCP System (20h)

  • HACCP Principles (10h)

    • Developing QP Programs

    • Processing and flowchart

    • Principle 1: Conduct a Hazard Analysis

    • Principle 2: Determine the Critical Control Points

    • Principle 3: Establish Critical Limits

    • Principle 4: Establish a Monitoring Sistem

    • Principle 5: Establish Corrective Actions

    • Principle 6: Establish Verification Procedures

    • Principle 7: Establish Documentation Concerning All Procedures and Records that are Appropriate to these Principles and their Application

    • An integrative approach to microbiological quality control in the winery

  • Prerequisite Programs

    • Good Agricultural Practice

    • Good Manufacturing Practice

  • Application of the HACCP System to Winemaking (2 h)

    • Applying HACCP to the Control of Ochratoxin A (OTA) in Wine

    • The 12 HACCP Tasks Applied to Ochratoxin A (OTA) in Wine

  • Winery sanitation (8h)

    • Basic Sanitation Principles

    • Safety Issues

    • Water Quality

    • Preliminary Cleaning

    • Detergents, Cleaners, And Surfactants

    • Rinses

    • Sanitizers

    • Sanitation Monitoring, Schedules And Documentation

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