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Questions and Answers

What is the primary advantage of non-culture dependent techniques?

  • Lower cost
  • Easier technical expertise
  • Faster results (correct)
  • Higher specificity

    • What is the primary limitation of non-culture dependent techniques?

  • Technical expertise
  • Slower results
  • Lower sensitivity
  • Higher cost (correct)

    • What is the primary function of PCR?

  • Detection of unculturable organisms
  • Amplification of specific DNA sequences (correct)
  • Sequencing of genetic material
  • Quantitation of microbial load

    • What is the primary function of qPCR?

    <p>Provides quantitative data on the amount of microbial DNA</p> Signup and view all the answers

    What is the primary function of Metagenomics?

    <p>Comprehensive analysis of microbial diversity</p> Signup and view all the answers

    What is the primary function of ELISA?

    <p>Rapid detection of pathogens</p> Signup and view all the answers

    What is the primary function of Lateral Flow Assay?

    <p>On-site, rapid screening for contaminants</p> Signup and view all the answers

    What is the primary function of Biosensors?

    <p>Real-time, continuous monitoring of food for microbial contamination</p> Signup and view all the answers

    What is the primary goal of biomass growth on waste substrate?

    <p>To optimize sustainability</p> Signup and view all the answers

    What is the main application of engineered pathways in food production?

    <p>To produce non-indigenous chemicals, proteins, or other biological substances</p> Signup and view all the answers

    What is the primary focus of Pasteur's contributions in the 19th century?

    <p>Proving that microorganisms are responsible for spoilage and fermentation</p> Signup and view all the answers

    What is the main advantage of refrigeration in food production?

    <p>It slows microbial growth, significantly reducing food spoilage and extending shelf life</p> Signup and view all the answers

    What is the main application of microbial genetics and genomics in food production?

    <p>Enhancing food safety and production through genetic manipulation</p> Signup and view all the answers

    What is the primary goal of single cell protein production?

    <p>To provide a primary protein source, complete food source, or health supplement</p> Signup and view all the answers

    What is the main advantage of using engineered pathways to produce non-indigenous chemicals, proteins, or other biological substances?

    <p>It enhances food safety and production</p> Signup and view all the answers

    What is the primary focus of Koch's discoveries in the 19th century?

    <p>Introducing methods for isolating pure cultures and identifying pathogens</p> Signup and view all the answers

    What is the primary goal of implementing HACCP in food production?

    <p>To prevent hazards in the production process</p> Signup and view all the answers

    What is the main advantage of culture dependent techniques in detecting microorganisms in food?

    <p>They allow for direct isolation and provide pure cultures of live organisms</p> Signup and view all the answers

    What is the main limitation of culture dependent techniques in detecting microorganisms in food?

    <p>They are time-consuming and labor-intensive</p> Signup and view all the answers

    What is the purpose of selective media in detecting microorganisms in food?

    <p>To inhibit the growth of unwanted microorganisms</p> Signup and view all the answers

    What is the main application of the plate count method in detecting microorganisms in food?

    <p>To determine the total viable count in food samples</p> Signup and view all the answers

    What is the purpose of enrichment cultures in detecting microorganisms in food?

    <p>To enhance the growth of specific microorganisms that may be present in low numbers</p> Signup and view all the answers

    What is the main difference between selective and differential media in detecting microorganisms in food?

    <p>Selective media promote the growth of target microorganisms, while differential media distinguish between species based on metabolic properties</p> Signup and view all the answers

    What type of food contains beneficial bacteria that promote health?

    <p>Probiotic functional foods</p> Signup and view all the answers

    What is the mechanism of anaerobic spoilage in canned goods?

    <p>Bacteria produce gas, causing swelling</p> Signup and view all the answers

    What is the primary symptom of Salmonellosis?

    <p>Fever and abdominal cramps</p> Signup and view all the answers

    What is the common food vector for Listeria monocytogenes?

    <p>Ready to eat deli meats</p> Signup and view all the answers

    What is the primary spoilage mechanism in milk?

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

    What is the disease caused by E.coli O157:H7?

    <p>Hemorrhagic colitis</p> Signup and view all the answers

    What is the common spoilage organism in cheese?

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

    What is the mechanism of spoilage in meat and poultry?

    <p>Protein degradation by bacteria</p> Signup and view all the answers

    What is the common parasite associated with foodborne illness?

    <p>Toxoplasma gondii</p> Signup and view all the answers

    What is the primary function of oxidation reduction potential in microorganisms?

    <p>To facilitate the loss of electrons in a substrate</p> Signup and view all the answers

    What type of microorganisms can grow over a wide range of temperatures?

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

    What is the term for the combination of intrinsic and extrinsic factors to control microbial growth?

    <p>Hurdle Concept</p> Signup and view all the answers

    What is the term for microorganisms that can grow in the presence or absence of oxygen?

    <p>Facultative Anaerobes</p> Signup and view all the answers

    What is the term for the ability of microorganisms to grow in low water activity environments?

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

    What is the term for the reduction of water activity in a food product?

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

    What is the term for the inhibition of microbial growth due to the presence of other microorganisms?

    <p>Competitive Exclusion</p> Signup and view all the answers

    What is the term for microorganisms that are sensitive to oxygen?

    <p>Obligate Anaerobes</p> Signup and view all the answers

    What is the primary purpose of yeast food in leavening?

    <p>To provide essential nutrients for yeast growth</p> Signup and view all the answers

    What is the optimal temperature range for Lactococcus lactis?

    <p>Below 40°C</p> Signup and view all the answers

    What is the primary function of rennet in cheese production?

    <p>To coagulate casein at pH 4.6</p> Signup and view all the answers

    What is the primary microorganism involved in the fermentation of sauerkraut?

    <p>Leuconostoc mesenteroides</p> Signup and view all the answers

    What is the primary function of LAB in cheese production?

    <p>To aid the action of rennin</p> Signup and view all the answers

    What is the primary advantage of using microbial rennet in cheese production?

    <p>Reduced production cost</p> Signup and view all the answers

    What is the primary difference between sauerkraut and pickles?

    <p>Type of microorganisms involved</p> Signup and view all the answers

    What is the primary purpose of mold inhibitors in bread production?

    <p>To prevent bread spoilage</p> Signup and view all the answers

    What is the primary advantage of fermenting food?

    <p>Enhancing the nutritional value and improving digestion</p> Signup and view all the answers

    What is the primary function of baker's yeast in bread production?

    <p>To produce large amounts of CO2 and cause dough to rise</p> Signup and view all the answers

    What is an osmophilic organism?

    <p>One that can grow in high-sugar environments</p> Signup and view all the answers

    What is the primary advantage of fermentation as a natural preservative method?

    <p>It can extend the shelf life of perishable foods without refrigeration</p> Signup and view all the answers

    What is the primary benefit of probiotics in fermented foods?

    <p>They can improve digestion and support gut health</p> Signup and view all the answers

    What is the primary difference between fermented and non-fermented foods?

    <p>Fermented foods contain probiotics and have a unique flavor and texture</p> Signup and view all the answers

    What is the primary role of microorganisms in fermented foods?

    <p>To convert substrates into different compounds and improve the flavor and texture of food</p> Signup and view all the answers

    What is the primary benefit of fermentation in food production?

    <p>It can improve the nutritional value and digestibility of food</p> Signup and view all the answers

    What is the typical duration of top fermentation?

    <p>1 week</p> Signup and view all the answers

    What is the primary cause of gushing in beer production?

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

    What is the primary characteristic of natural wines?

    <p>Contain 9-14% alcohol</p> Signup and view all the answers

    What is the primary difference between still wines and sparkling wines?

    <p>Sparkling wines have appreciable CO2 under pressure</p> Signup and view all the answers

    What is the primary function of the treatment stage in beer production?

    <p>Inoculation of yeasts</p> Signup and view all the answers

    What is the primary cause of biological turbidities in beer?

    <p>Poor hygiene and pasteurization</p> Signup and view all the answers

    What is the primary characteristic of fortified wines?

    <p>Contain 15 to 21% alcohol</p> Signup and view all the answers

    What is the primary cause of off-flavor in beer?

    <p>Formation of mertacaptans when exposed to sun</p> Signup and view all the answers

    What is the primary function of Pediococcus halophilus in the fermentation of soy sauce?

    <p>Producing lactic acid</p> Signup and view all the answers

    What is the main difference between top-fermented and bottom-fermented beer?

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

    What is the purpose of hops in beer production?

    <p>To provide a bitter taste and aroma</p> Signup and view all the answers

    What is the primary role of barley malt in beer production?

    <p>To provide a high beta amylase activity</p> Signup and view all the answers

    What is the effect of calcium on the flavor of beer?

    <p>It enhances the flavor of beer</p> Signup and view all the answers

    What is the primary problem associated with brewer's yeast?

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

    What is the purpose of the mashing step in beer production?

    <p>To convert starch into fermentable sugars</p> Signup and view all the answers

    What is the primary function of Saccharomyces cerevisiae in beer production?

    <p>To produce alcohol</p> Signup and view all the answers

    What is the primary purpose of adding yeast to the mixture in the Tank Method?

    <p>To convert sugar into alcohol and carbon dioxide</p> Signup and view all the answers

    What is the name of the mixture added to the wine before bottling?

    <p>Liqueur d'Expedition</p> Signup and view all the answers

    What is the primary purpose of distillation in spirits production?

    <p>To separate the alcohol from the grain particles and congeners</p> Signup and view all the answers

    What is the term for the process of converting starch into sugar in spirits production?

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

    What is the primary purpose of ageing certain distilled spirits in wooden casks?

    <p>To mature the spirit and develop its flavor, aroma, and color</p> Signup and view all the answers

    What is the term for the process of combining two or more spirits of the same category?

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

    What is the term for the process of grinding raw material into a coarse meal?

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

    What is the primary purpose of filtering the wine in the Tank Method?

    <p>To remove sediment from the wine</p> Signup and view all the answers

    Which type of food is more associated with foodborne diseases?

    <p>Foods of animal origin</p> Signup and view all the answers

    What is the main concern of food spoilage?

    <p>Economic loss and food wastage</p> Signup and view all the answers

    What is the purpose of using genetic engineering techniques in food processing?

    <p>To produce novel and better strains of microorganisms</p> Signup and view all the answers

    What is the application of microbial enzymes in food production?

    <p>To produce food additives</p> Signup and view all the answers

    What is the purpose of developing antimicrobial metabolites of desirable microorganisms?

    <p>To control pathogenic and spoilage microorganisms</p> Signup and view all the answers

    What is the primary focus of food bio preservation?

    <p>To control pathogenic and spoilage microorganisms</p> Signup and view all the answers

    What is the main advantage of using microbial enzymes in food production?

    <p>They are of higher purity and activity</p> Signup and view all the answers

    What is the primary benefit of consuming fermented foods?

    <p>They have greatly increased in consumption over the last 15 to 20 years</p> Signup and view all the answers

    What is the primary mechanism by which probiotics act to confer health benefits to the host?

    <p>By improving or restoring the gut flora</p> Signup and view all the answers

    Which of the following is an example of an intrinsic factor that affects the growth of microorganisms in food?

    <p>Nutrient composition</p> Signup and view all the answers

    What is the primary significance of microorganisms in food, related to foodborne diseases?

    <p>They can cause foodborne diseases of microbial origin</p> Signup and view all the answers

    What is the primary application of microorganisms in bread production?

    <p>They are used to ferment sugars to produce ethanol and CO2</p> Signup and view all the answers

    What is the primary role of bacteria in cheese production?

    <p>To lower the pH and coagulate milk proteins</p> Signup and view all the answers

    Which type of dairy product relies on both bacteria and yeasts?

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

    Which of the following types of microorganisms can function as probiotics?

    <p>Both bacteria and certain types of yeast</p> Signup and view all the answers

    What is the primary function of mold in blue cheese production?

    <p>To give the cheese its unique flavor and texture</p> Signup and view all the answers

    What is the primary goal of controlling microbial growth in foods?

    <p>To prevent the growth of pathogenic microorganisms</p> Signup and view all the answers

    What is the primary significance of microorganisms in food, related to food spoilage?

    <p>They can cause food spoilage</p> Signup and view all the answers

    Which of the following fermented dairy products is not commonly found in East-Asian cuisine?

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

    What is the primary purpose of bacteria in fermented meat and fish products?

    <p>To lower the pH and prevent spoilage</p> Signup and view all the answers

    Which of the following is an example of a probiotic food?

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

    Which of the following fermented vegetable products is not made with bacteria?

    <p>Miso soup</p> Signup and view all the answers

    What is the primary function of yeast in wine production?

    <p>To ferment sugars and produce ethanol</p> Signup and view all the answers

    Which of the following fermented soybean products is not typically made with mold?

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

    What is the primary purpose of fermentation in chocolate production?

    <p>To destroy the seed coating of the cocoa beans</p> Signup and view all the answers

    What is the primary function of yeasts in kombucha production?

    <p>To break down sugars into ethanol and carbon dioxide</p> Signup and view all the answers

    What is the primary advantage of using mycoprotein as a meat alternative?

    <p>It can mimic many different existing meat products</p> Signup and view all the answers

    What is the primary difference between kvass and kombucha?

    <p>Kvass is made from fermented rye and bread, while kombucha is made from sweetened tea</p> Signup and view all the answers

    What is the primary role of bacteria in pickle production?

    <p>To lower the pH and preserve the pickles</p> Signup and view all the answers

    What is the primary advantage of using fermentation in food production?

    <p>It increases the shelf life of the food</p> Signup and view all the answers

    What is the primary function of yeast extracts in condiments and sauces?

    <p>To add flavor to the condiment or sauce</p> Signup and view all the answers

    What is the primary difference between Worcestershire and fish sauce?

    <p>Fish sauce is more popular in Asia, while Worcestershire sauce is more popular in Europe</p> Signup and view all the answers

    What is the primary reason why microorganisms are used in food production?

    <p>To ferment and break down food components</p> Signup and view all the answers

    What is the estimated annual cost of food-borne illnesses in the United States?

    <p>$6.9 billion</p> Signup and view all the answers

    Who is credited with developing canning as a method of food preservation?

    <p>Nicolas Appert</p> Signup and view all the answers

    What is the term for the science of studying microorganisms in food?

    <p>Food microbiology</p> Signup and view all the answers

    What is the primary purpose of studying food microbiology?

    <p>To ensure food safety and quality</p> Signup and view all the answers

    What is the primary mechanism of food spoilage?

    <p>Microbial growth</p> Signup and view all the answers

    What is the estimated number of cases of food-borne illnesses in the United States annually?

    <p>26 million</p> Signup and view all the answers

    What is the primary goal of food preservation?

    <p>To extend shelf life</p> Signup and view all the answers

    Study Notes

    Biomass Growth and Food Additives

    • Biomass growth on waste substrates to optimize sustainability
    • Production and purification of native and recombinant food additives for nutrition, taste, and odour
    • Engineered pathways to produce non-indigenous chemicals, proteins, or other biological substances

    Meat and Dairy Alternatives

    • Microbial meat analogues recreating nutrition, taste, and texture
    • Production of animal products components in cell factories
    • Engineered nutritional or texture elements allowing for closer meat resemblance
    • Animal flavorings produced in cells

    Single Cell Protein

    • Microbial food product including primary protein source, complete food source, and health supplement
    • Engineered to improve nutrition and taste compounds
    • Growth on waste substrates to optimize sustainability

    Development of Food in Microbiology

    19th Century

    • Pasteur's contributions: proved that microorganisms are responsible for spoilage and fermentation
    • Koch's discoveries: introduced methods for isolating pure cultures and identifying pathogens

    20th Century

    • Refrigeration: slowed microbial growth, significantly reducing food spoilage and extending shelf life
    • Antibiotics: introduced in food production to prevent and control bacterial contamination

    Advancements in Food Microbiology

    Microbial Genetics and Genomics

    • Understanding microbial DNA has allowed for genetic manipulation and the development of genetically modified organisms (GMOs) to enhance food safety and production

    HACCP (Hazard Analysis Critical Control Point)

    • A preventive approach to food safety that identifies critical control points in the production process to prevent hazards

    Probiotics and Functional Foods

    • Foods containing beneficial bacteria that promote health, such as yogurt with live culture

    Detection of Organisms in Food

    Culture Dependent Techniques

    • Methods that rely on the growth of microorganisms on a specific media to identify and quantify them
    • Advantages: directly isolates and provides pure cultures of live organisms for analysis, allows for enumeration and detailed study of microbial colonies
    • Limitations: time-consuming and labor-intensive, not all microorganisms are culturable

    Types of Culture Dependent Methods

    • Plate Count Method: procedure involves serial dilution of food samples, nutrient agar plating, incubation, and counting of colony forming units (CFU)
    • Selective and Differential Media: selective media contain agents that inhibit the growth of unwanted microorganisms, while differential media distinguish between species based on metabolic properties
    • Enrichment Cultures: enhances the growth of specific microorganisms that may be present in low numbers

    Non-Culture Dependent Techniques

    • Methods that detect microorganisms without the need for their growth in culture media
    • Advantages: faster results, higher sensitivity and specificity, capable of detecting viable but non-culturable (VBNC) microorganisms
    • Limitations: may require sophisticated equipment and technical expertise, typically more expensive

    Types of Non-Culture Dependent Techniques

    • Molecular Techniques: PCR (Polymerase Chain Reaction), qPCR (Quantitative PCR), and Metagenomics
    • Immunological Techniques: ELISA (Enzyme-Linked Immunosorbent Assay), Lateral Flow Assay, and Biosensors

    Case Study: Salmonella Detection

    • Culture Dependent Methods: enrichment using selective broth, selective media, and plate count method
    • Non-Culture Dependent Methods: PCR, ELISA, and Biosensors

    Canned Goods

    • Mechanism of anaerobic spoilage: bacteria produce gas, causing swelling and spoilage
    • Common spoilage organisms: clostridium, bacillus

    Disease Causing Microorganisms (Pathogens)

    • Microorganisms that can cause foodborne illnesses when ingested
    • Common pathogens: bacteria, viruses, and parasites

    Causative Agents of Diseases and Associated Food Vectors

    • Salmonella: disease caused by salmonellosis, symptoms include diarrhea, fever, and abdominal cramps, common food vectors include raw or undercooked poultry, eggs, and contaminated produce
    • E.coli O157:H7: disease caused by hemorrhagic colitis and HUS, symptoms include severe stomach cramps, bloody diarrhea, and vomiting, common food vectors include undercooked beef, contaminated raw vegetables, and unpasteurized milk
    • Listeria monocytogenes: disease caused by listeriosis, symptoms include fever, muscle aches, and nausea, common food vectors include ready-to-eat deli meats, unpasteurized dairy, and smoked seafood

    Spoilage Mechanisms in Dairy Products

    • Milk: spoilage mechanisms include lactic acid fermentation and proteolytic activity, common spoilage organisms include lactobacillus and pseudomonas
    • Cheese: spoilage mechanisms include mold growth and yeast fermentation, common spoilage microorganisms include penicillium and candida

    Spoilage Mechanisms in Meat and Poultry

    • Protein degradation: bacteria produce enzymes that break down proteins into amino acids and peptides, leading to foul odors
    • Lipid oxidation: microbial lipases degrade fats, causing rancidity

    Oxidation Reduction Potential

    • O/R Potential (Eh): ease with which substrate loses or gains electrons
    • Types of microorganisms: aerobic, anaerobic, microaerobic, and facultative anaerobes

    Others

    • Nutrients: fastidious vs. non-fastidious microorganisms
    • Biological Structure: affects growth and survival of microorganisms
    • Antimicrobial factors: naturally occurring factors that inhibit microbial growth

    Extrinsic Factors

    • Temperature: affects microbial growth, with different microorganisms having optimal growth temperatures
    • Other factors: relative humidity, environmental gasses, and presence of other microorganisms

    Fermented Foods

    • Fermented foods are processed through the activities of microorganisms, offering several advantages:
      • Enhanced nutritional value: Fermentation increases the availability of nutrients and improves digestibility.
      • Improved digestion: Fermented foods contain probiotics, which support gut health and balance the gut microbiome.
      • Extended shelf life: Fermentation acts as a natural preservative, extending the shelf life of perishable foods without refrigeration or artificial preservatives.
      • Enhanced flavor and texture: Fermentation develops unique flavors and textures that are often complex and desirable.
      • Safety: Fermentation reduces the presence of harmful microorganisms in food.
      • Economic benefits: Fermentation requires minimal equipment and ingredients, making it an economical method of food preservation and preparation.

    Bread

    • Ingredients: Flour, water, salt, yeast, and additives like sugar and salt.
    • Baker's yeast (Saccharomyces cerevisiae) is used in bread making due to its:
      • Easy dispersal in water
      • Rapid growth at 20-25°C
      • Ability to produce large amounts of CO2
      • Good keeping quality
      • Ability to adapt to rapidly changing substrates
      • High enzyme activity
      • Ability to grow in anaerobic conditions
      • Osmophilic properties
      • High competitiveness
    • Factors affecting leavening:
      • Osmotic pressure
      • Sugar nature
      • Nitrogen and nutrient effects
      • Fungal inhibitors
      • Yeast concentration
    • Enzymes used in bread making:
      • Amylase from Bacillus subtilis
      • Proteolytic enzyme from Aspergillus oryzae
    • Mold inhibitors used to avoid bread spoilage:
      • Antimycotics

    Cheese

    • Lactic acid bacteria (LAB) are used in cheese production:
      • Lactococcus lactis: grows at temperatures below 40°C
      • Streptococcus thermophilus, Lactobacillus bulgaricus, and L. helveticus: grow at temperatures above 40°C
    • Uses of LAB in cheese production:
      • Coagulation of casein at pH 4.6
      • Aids the action of rennin
      • Shrinkage of curd
      • Contributes to flavor
    • Disadvantages of using LAB:
      • Attack by bacteriophages
      • Undesirable strain
      • Inhibition by antibiotics
      • Inhibition by sterilant and detergent residues

    Yogurt

    • Yogurt is a fermented milk product that originated from the Turks, meaning "to blend".
    • Microorganisms involved in yogurt production:
      • Lactococcus spp.
      • Lactobacillus spp.
      • Lactic acid
    • Lactic acid lowers the pH for milk coagulation and inhibits the growth of spoilage bacteria.

    Fermented Vegetables

    • Sauerkraut:
      • Fermentation of cabbages
      • Initiated by Leuconostoc mesenteroides, followed by LAB, gram-negative coliforms, and pseudomonads
      • Flavor comes from different metabolites
      • Temperature: 15°C
      • Salt: about 2.5% salt
    • Pickles:
      • Production methods: dry salting and brine salting
      • Microorganisms involved are similar to those in sauerkraut, but Leuconostoc sp. is not the dominant species
      • Major organisms involved:
        • Lactobacillus plantarum
        • L. brevis
        • Pediococcus spp.

    Soy Sauce (Shoyu)

    • Microorganisms involved in soy sauce production (moromi):
      • Pediococcus halophilus (lactic acid production)
      • Saccharomyces rouxii (alcohol production)
      • Torulopsis spp. (phenolic compounds and flavor)

    Fermented Beverages

    • Beer:
      • Types:
        • Top-fermented (ale): fermented with top-fermenting yeast strains at warmer temperatures (15-25°C)
        • Bottom-fermented (lager): fermented with bottom-fermenting yeast strains at cooler temperatures (7-13°C)
      • Ingredients:
        • Barley malt
        • Hops
        • Adjuncts (starch products)
        • Water
      • Brewer's yeast:
        • Produces alcohol under aerobic conditions
        • Produces balanced proportion of metabolites for flavor
      • Problems:
        • Mutation
        • Contamination

    Wine

    • Broad classification of grape wines:
      • Natural wines (9-14% alcohol): dependent on complete yeast fermentation and protection from air
        • Still wines (table wines): white, rose, and red, with no carbon dioxide added
        • Sparkling wines: white, rose, and red, with appreciable CO2 under pressure
      • Fortified wines (15-21% alcohol): dependent on addition of distilled grape spirit
        • Sweet wines
        • Liqueur d'Expedition (mixture of base wine, sugar, and yeast)
    • Bulk production/Charmat process:
      1. Base wine + sugar + yeast mixture is added to an autoclave
      2. Second fermentation occurs in about 10 days
      3. Filtering removes sediment
      4. Dosage: sugar/must mixture is added before bottling

    Distilled Spirits

    • Measurement of alcoholic strength:
      • Proof
      • Percentage by weight
      • Percentage by volume
    • Preparing: grinding raw material into a coarse meal to break down protective hull and free starch
    • Mashing: converting starch to sugar by mixing with pure water and cooking
    • Fermenting: converting sugar to alcohol and CO2 by adding yeast
    • Distilling: heating the mixture to vaporize alcohol, which is then cooled and condensed into clear drops of distilled spirits
    • Ageing: maturing certain distilled spirits in wooden casks to develop taste, aroma, and color
    • Blending: combining two or more spirits of the same category to create a unique flavor profile

    Microorganisms and Food

    • Microorganisms are tiny organisms that live all around us and on us, and are classified into three main groups: bacteria, viruses, and fungi (e.g. yeasts and moulds).
    • While some microorganisms are undesirable and cause food spoilage or illness, others are used to make food, such as cheese, yoghurt, and bread.

    History of Microorganism Use in Foods

    • Microorganisms have been used to make food for millennia, with evidence of beer production dating back to 7000 BC and cheese consumption dating back to 3000 BC.
    • The techniques used to make these products have evolved over time, becoming more advanced and controlled.

    Importance of Microorganisms in Foods

    • Studying food microbiology is crucial to provide clean, safe, and healthful food to consumers, prevent food spoilage, and prevent food-borne illnesses.
    • Food microbiology helps to control microbial growth, preserve food, and produce fermented foods.

    Food-Borne Illness

    • Food-borne illnesses are a significant problem, with the Economic Research Service (ERS) estimating a yearly cost of $6.9 billion and the Centers for Disease Control and Prevention (CDC) estimating 26 million cases annually, resulting in 325,000 hospitalizations and 5,000 deaths.

    Food Spoilage

    • All foods, except sterile foods, harbor microorganisms, which can cause spoilage and lead to economic loss and food wastage.
    • New concepts are being studied to reduce contamination and control the growth of spoilage microbes in foods.

    Food Processing

    • Many food-grade microorganisms are used to produce fermented foods from raw materials from animal and plant sources.
    • The production and availability of these microorganisms have increased significantly over the last 15-20 years and are expected to continue to grow.

    Food Additives

    • Microbial enzymes are used to produce food and food additives, such as essential amino acids, color compounds, flavor compounds, stabilizers, and organic acids.
    • Genetic recombination techniques are used to develop novel and better strains of microorganisms.

    Food Bio Preservation

    • Antimicrobial metabolites of desirable microorganisms are being developed and used in foods to control pathogenic and spoilage microorganisms.
    • These compounds are produced economically and have generated significant interest.

    Probiotics

    • Probiotics are live microorganisms used as food and feed supplements to confer health benefits on the host.
    • They act by improving or restoring the gut flora and are mainly bacteria, but certain types of yeasts can also function as probiotics.
    • Probiotic foods include yogurt, kefir, sauerkraut, tempeh, and kimchi.

    Factors Affecting Growth of Microorganisms in Food

    Intrinsic Factors

    • pH
    • Water activity
    • Redox potential
    • Nutrient composition
    • Inhibitory substances
    • Biological structures

    Extrinsic Factors

    • Relative humidity
    • Temperature
    • Atmospheric gases
    • Other microbial flora

    Significance

    • Microorganisms play a crucial role in food, including food-borne diseases, microbial food spoilage, beneficial uses of microbes in food, and control of microbial growth in foods.

    Applications

    • Microorganisms are used in various food products, including bread, dairy products, alcoholic drinks, soy-based products, fermented meat and fish, vegetables, condiments and sauces, drinks, mycoprotein, and chocolate.

    Sample Applications

    Bread

    • Yeast is used to ferment sugars to produce ethanol and CO2, which helps the bread rise.
    • Some breads, such as sourdough, use bacteria to produce lactic acid and give them a distinctive sour taste.

    Dairy Products

    • Microorganisms are used to produce cheese, with bacteria creating a low pH and coagulating milk proteins.
    • Blue cheese contains mold, which gives it a unique characteristic.
    • Various microorganisms are added to the outside of cheeses to alter the final product.

    Alcoholic Drinks

    • Yeast is used to ferment sugars to produce ethanol and CO2, which is typically released in still drinks.
    • Sparkling wines and beers retain CO2, which helps to form bubbles or foam.

    Soy-based Products

    • Fermentation is used to produce soy sauce, miso paste, and tempeh.

    Fermented Meat and Fish

    • Fermented meat and fish products are common in some countries, with bacteria used to lower the pH and prevent spoilage.

    Vegetables

    • Fermentation is used to produce kimchi, sauerkraut, and pickles.

    Condiments and Sauces

    • Microorganisms are used to produce yeast extracts, Worcestershire and fish sauce, and vinegar.

    Drinks

    • Fermentation is used to produce kombucha, kvass, and other drinks.

    Mycoprotein

    • Mycoprotein is a meat alternative created from a fungus, with the fungus allowed to grow in large batches before being processed into a final product.

    Chocolate

    • Fermentation is used to process cocoa beans, destroying the unwanted seed coating and producing desirable flavors.

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