🎧 New: AI-Generated Podcasts Turn your study notes into engaging audio conversations. Learn more

Microorganisms in Food Industry
38 Questions
4 Views

Microorganisms in Food Industry

Created by
@ProperHeliotrope8233

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of enzymes in fermentation?

  • To produce bacteriocins and vitamins
  • To convert lactate into glucose
  • To synthesize polysaccharides, proteins, and lipids
  • To hydrolyze polysaccharides, proteins, and lipids (correct)
  • Which of the following is NOT a benefit of fermented foods?

  • Enrichment of food substrates biologically with vitamins and essential amino acids
  • Increased risk of foodborne illness (correct)
  • Enrichment of the human dietary through development of flavors and aromas
  • Detoxification during food fermentation processing
  • Which type of microorganism is responsible for producing lactic acid in fermentation?

  • Yeast
  • Bifidobacterium
  • Mold
  • Lactic Acid Bacteria (LAB) (correct)
  • What is the end product of homofermentation?

    <p>1 mol of glucose into 2 mol of lactate</p> Signup and view all the answers

    Which of the following microorganisms is NOT a type of Lactic Acid Bacteria (LAB)?

    <p>Bifidobacterium</p> Signup and view all the answers

    What is the primary role of bacteriocins in fermentation?

    <p>To preserve food by inhibiting the growth of other microorganisms</p> Signup and view all the answers

    Which of the following is an example of a yeast used in fermentation?

    <p>Saccharomyces cerevisiae</p> Signup and view all the answers

    What is the purpose of fermentation in food processing?

    <p>To convert raw materials into fermented foods</p> Signup and view all the answers

    What is a key characteristic of a probiotic strain?

    <p>Ability to produce antimicrobial substances</p> Signup and view all the answers

    What is one of the benefits of probiotics in reducing colon cancer?

    <p>By reducing the growth of harmful bacteria</p> Signup and view all the answers

    What is a necessary step in the production of probiotics?

    <p>Fermentation</p> Signup and view all the answers

    What is a key factor in the competitiveness of a probiotic strain?

    <p>Ability to adhere to intestinal epithelia</p> Signup and view all the answers

    What is one of the effects of probiotics on the gut microbiota?

    <p>Antagonism against pathogenic bacteria</p> Signup and view all the answers

    What is a beneficial effect of probiotics on lactose intolerance?

    <p>Hydrolysis of lactose</p> Signup and view all the answers

    Which of the following acids provides an unfavourable environment for the growth of many pathogenic and spoilage microorganisms?

    <p>Lactic acid</p> Signup and view all the answers

    What is a characteristic of a probiotic strain that ensures its survival in the gut?

    <p>Ability to resist bile acid and digestive enzymes</p> Signup and view all the answers

    What is the primary mechanism of action of bacteriocins produced by LAB?

    <p>Depolarization of the target cell membrane</p> Signup and view all the answers

    What is a requirement for a probiotic strain to be considered beneficial?

    <p>Origin from the intestinal tract of healthy persons</p> Signup and view all the answers

    What is a characteristic of reuterin produced by strains of Lactobacillus reuteri?

    <p>It is an equilibrium mixture of monomeric, hydrated monomeric and cyclic dimeric forms of h-hydroxypropionaldehyde</p> Signup and view all the answers

    Which of the following is NOT a desirable property of bacteriocins produced by LAB for food preservation?

    <p>They are active and toxic on eukaryotic cells</p> Signup and view all the answers

    How can bacteriocins be used to supplement foods?

    <p>By using ex situ produced bacteriocin preparations</p> Signup and view all the answers

    What is a benefit of using bacteriocins as a food preservation method?

    <p>It permits the marketing of “novel” foods without compromising food safety</p> Signup and view all the answers

    What is the characteristic of Lactococcus, Pediococcus, and Streptococcus?

    <p>They produce only lactic acid.</p> Signup and view all the answers

    What is the main difference between natural fermentation and controlled fermentation?

    <p>The level of inoculation with starter culture.</p> Signup and view all the answers

    What is the purpose of cryoprotectant agents in concentrated frozen cultures?

    <p>To reduce cell death and injury during freezing and thawing.</p> Signup and view all the answers

    What is a common problem associated with starter cultures?

    <p>All of the above.</p> Signup and view all the answers

    What is the effect of antibiotics in raw material on starter cultures?

    <p>They inhibit the growth of microorganisms.</p> Signup and view all the answers

    What is the primary factor that affects the effectiveness of fermentation in controlling the growth of foodborne pathogens?

    <p>All of the above.</p> Signup and view all the answers

    What is the purpose of biopreservation?

    <p>To extend the shelf-life and improve the safety of food using microorganisms and/or their metabolites.</p> Signup and view all the answers

    What is the characteristic of Leuconostoc?

    <p>It produces equimolar amounts of lactic acid, acetic acid, CO2, and ethanol.</p> Signup and view all the answers

    What is the effect of a bacteriostatic agent on microorganisms?

    <p>Inhibition of growth and reproduction of microorganisms</p> Signup and view all the answers

    What is the minimum concentration of an antimicrobial necessary to inhibit the growth of a particular strain of microorganism?

    <p>Minimum inhibition concentration (MIC)</p> Signup and view all the answers

    What is the effect of a bactericidal agent on microorganisms?

    <p>Complete killing of a defined number of microorganisms</p> Signup and view all the answers

    What is a target of food antimicrobials?

    <p>All of the above</p> Signup and view all the answers

    What is a factor that affects the antimicrobials activity in food?

    <p>All of the above</p> Signup and view all the answers

    What is the lowest concentration of an antimicrobial able to produce complete killing of a defined number of bacteria?

    <p>Minimum bactericidal concentration (MBC)</p> Signup and view all the answers

    Why are food antimicrobials not a substitute for good sanitation in food processing plants?

    <p>Because they are not a substitute for good sanitation practices</p> Signup and view all the answers

    What is the effect of a bacteriostatic agent on the number of microorganisms?

    <p>No change in the number of microorganisms</p> Signup and view all the answers

    Study Notes

    Beneficial Microorganisms in Food Industry

    • Microorganisms are used in the food industry in several ways, including:
      • Actively growing cells for fermentation
      • Metabolic by-products, such as bacteriocins, vitamins, amino acids, and Single-Cell Protein (SCP)
      • Cellular components, such as enzymes

    Fermentation

    • Fermentation is a process where raw materials are converted into fermented foods by the growth and metabolic activities of edible microorganisms
    • Microorganisms' enzymes, such as amylases, proteases, and lipases, hydrolyze polysaccharides, proteins, and lipids to produce nontoxic products with pleasant flavors, aromas, and textures

    Benefits of Fermented Foods

    • Enrichment of the human diet through development of diverse flavors, aromas, and textures
    • Preservation of substantial amounts of food through lactic acid, alcoholic, acetic acid, alkaline, and high salt fermentations
    • Enrichment of food substrates biologically with vitamins, protein, essential amino acids, and essential fatty acids
    • Detoxification during food fermentation processing

    Microorganisms Used in Fermentation

    • Lactic Acid Bacteria (LAB): Lactococcus lactis, Streptococcus thermophilus, Leuconostoc spp., Lactobacillus spp., Pediococcus spp.
    • Related bacteria: Aerococcus, Microbacterium, Propionibacterium, Carnobacterium, Non LAB Bifdobacterium
    • Yeasts: Saccharomyces cerevisiae, Saccharomyces spp., Zygosaccharomyces
    • Molds: Aspergillus, Rhizopus, Penicillium, Botrytis

    Types of Fermentation

    • Homofermentation: produces only lactic acid, such as Lactococcus, Pediococcus, and Streptococcus
    • Heterofermentation: produces equimolar amounts of lactic acid, acetic acid, CO2, and ethanol, such as Leuconostoc

    Types of Fermentation by LAB

    • Natural fermentation: carried out by natural microflora, such as Lactobacillus sp and Leuconostoc mesenteroides
    • Controlled fermentation: uses high numbers of pure culture of single or mixed strains or species of microorganisms, with controlled acidification

    Starter Cultures

    • Concentrated frozen cultures: prepared by growing cells in a suitable medium, concentrating by centrifugation, and resuspending in a liquid with cryoprotectant agents
    • Freeze-dried concentrates: prepared by drying concentrated frozen cells under vacuum

    Problems with Starter Cultures

    • Strain antagonisms: production of compatible strains to avoid strain antagonism
    • Loss of a desired trait: physical and chemical stresses can result in loss of a trait
    • Cell death and injury: ensuring a large number of viable cells and a short lag phase
    • Inhibitors in raw material: antibiotics, sanitizers, nitrite, or phosphate in cured meat

    Factors Affecting the Effectiveness of Fermentation

    • Initial product pH
    • Buffering capacity and food composition
    • Nature and concentration of fermentable Carbohydrates (CHO)
    • Rate of growth of LAB and targeted pathogens

    Biopreservation

    • Refers to the extension of the shelf-life and improvement of the safety of food using microorganisms and/or their metabolites
    • Organic acids, such as lactic, acetic, and propionic acids, provide an acidic environment unfavorable for the growth of many pathogenic and spoilage microorganisms
    • Production of a range of other antimicrobial metabolites, such as H2O2, diacetyl, reuterin, and reuterocyclin
    • Bacteriocins: proteinaceous inhibitors produced by LAB, acting through depolarization of the target cell membrane or inhibition of cell wall synthesis

    Benefits of Bacteriocins

    • Generally recognized as safe (GRAS) substances
    • Not active and non-toxic on eukaryotic cells
    • Become inactivated by digestive proteases, having little influence on the gut microbiota
    • Show a bactericidal mode of action, usually acting on the bacterial cytoplasmic membrane
    • Permit the marketing of novel foods (less acidic, lower salt content) without compromising food safety

    Probiotics

    • Beneficial effects on human health:
      • Lactose hydrolysis (lactose intolerance)
      • Reduce serum cholesterol level
      • Reduce colon cancer
      • Reduce intestinal disorders
    • Benefits thought to occur via:
      • Biochemical effects (altering associated metabolic and enzymatic activities of resident harmful or developing pathogens)
      • Competition for nutrients
      • Competition for binding sites

    What it Takes to be a Probiotic

    • Known microorganism origin from the intestinal tract of healthy persons
    • Stability during production, growth, or fermentation, concentration, freezing, drying, distribution, etc.
    • No adverse sensory properties
    • Genetic stability
    • Stability during incorporation into food/feed; pH, heat, drying, encapsulation, etc.
    • Competitiveness: stability at target site, resistant to bile acid and digestive enzymes, able to compete with normal microflora, resistant to antimicrobials produced by bacteria

    Minimum Inhibition Concentration (MIC) and Minimum Bactericidal Concentration (MBC)

    • MIC: the minimum concentration of an antimicrobial necessary to inhibit the growth of a particular strain of microorganism
    • MBC: the lowest concentration of an antimicrobial able to produce complete killing of a defined number of bacteria, in defined media and within a defined time

    Targets of Food Antimicrobials

    • Cell membrane or cell wall: increasing permeability and loss of cellular constituents
    • Inactivation of essential metabolic enzymes, protein synthesis, and genetic material
    • Transport mechanism for nutrients

    Factors Affecting Antimicrobial Activity in Food

    • Level and type of microorganism
    • Storage conditions of food product, such as time, temperature, and humidity

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Explore the role of microorganisms in food production, including fermentation and metabolic by-products. Learn how microorganisms contribute to food manufacturing and processing.

    More Quizzes Like This

    Food Microbiology Cultivation Quiz
    5 questions
    Food Microbiology Chapter 2.1
    10 questions
    Bacterial Groups in Food Science
    37 questions
    Use Quizgecko on...
    Browser
    Browser