Food micro microbial growth

• What is the main reproductive method for bacteria and archaea?


  Binary fission
• What is the process of binary fission in bacteria?

  It involves cell elongation, DNA replication, FtsZ protein forming a septum, nucleoid segregation, and cell division.
• How long can the duration of binary fission be for E. coli?

  As short as 20 minutes
• What are the phases of the bacterial growth curve?

  • Lag Phase
  • Exponential (Log) Phase
  • Stationary Phase
  • Death (Decline) Phase
• What is the term for the time it takes for a population to double in number?

  Generation time
• How do you calculate generation time?

  Generation time can be calculated using the formula \( g = \frac{t}{n} \), where \( t \) is the total time and \( n \) is the number of generations.
• What occurs during the stationary phase of microbial growth?

  During the stationary phase, the growth rate slows and the number of viable cells remains constant due to nutrient depletion and waste accumulation.
• What are micro-organisms in food primarily classified as?


  Bacteria, fungi, and algae
• What is the definition of bacteria in food production?


  Single-celled prokaryotic organisms
• Name a key type of bacteria used in food production.

  Lactic acid bacteria (e.g., Lactobacillus)
• What is one function of lactic acid bacteria in food production?


  Fermentation (e.g., cheese, yogurt)
• What is an example of cyanobacteria used in food?


  Spirulina
• What role do probiotics play in gut health?


  They promote beneficial bacteria in the digestive system
• What are fungi defined as in the context of food production?


  Eukaryotic organisms, neither plant nor animal
• What are the characteristics of fungi?


  Can be single-celled or multicellular, absorb nutrients from surroundings, reproduce via spores
• What are the three major groups of fungi?


  Multicellular filamentous molds, macroscopic filamentous fungi, single-celled microscopic yeasts
• What is the structure of molds in fungi?


  Composed of fine threads called hyphae
• What do macroscopic fungi produce?


  Visible fruiting bodies (mushrooms)
• How do yeasts reproduce?


  By budding
• What is the importance of fungi in food?


  Fermentation, flavor development, texture
• What defines algae in food production?


  Photosynthetic organisms, distinct from plants
• What are the characteristics of algae?


  Contain chlorophyll and other pigments, range from microscopic to large seaweeds
• What are the types of algae mentioned?


  Green algae, red algae, brown algae
• What are the uses of algae in food production?


  Nutritional products, direct food sources
• What are the applications of micro-organisms in food?


  • Fermented food production: cheese, yogurt (bacteria), bread, wine (yeast), soy sauce (bacteria, mold, yeast)
  • Nutritional enhancement: probiotics (bacteria)
  • Direct food sources: black moss (cyanobacteria), chlorella, seaweed (green algae), mycoprotein (fungi)
• What are examples of fermented foods produced by bacteria?


  Cheese and yogurt
• What is a key species of molds used in fermented foods?

  Aspergillus oryzae
• What applications do molds have in fermented foods?


  Soy sauce and miso production
• What is a key species of yeast used in fermented foods?

  Saccharomyces cerevisiae
• What is the function of yeast in food production?


  Converts sugars to alcohol and CO2 through fermentation
• Why is yeast important in bread making?


  Essential for leavening in bread
• What is the process of cheese production?

  1. Milk is pasteurized
  2. Starter cultures (bacteria) are added
  3. Rennet is added to curdle the milk
  4. Curd is cut and whey is drained
  5. Curd is aged to develop flavor and texture
• What are the steps in yogurt production?

  1. Milk is heated and cooled
  2. Starter cultures (lactic acid bacteria) are added
  3. Mixture is incubated at a specific temperature
  4. Fermentation occurs, thickening the yogurt
  5. Yogurt is cooled and packaged
• What are the processes involved in producing fermented vegetables and meats?


  • Vegetables: Salt is added to create an anaerobic environment, allowing lactic acid bacteria to ferment.
  • Meats: Salt and spices are used to inhibit spoilage bacteria while allowing fermentation by specific bacteria.
• What are the applications of micro-organisms in bread, beer, and wine production?


  • Bread: Yeast ferments sugars, producing CO2 for leavening.
  • Beer: Yeast ferments sugars from grains, producing alcohol.
  • Wine: Yeast ferments sugars in grapes, producing alcohol and flavor compounds.
• What are probiotics and their role in nutrition?


  Probiotics enhance nutritional value by promoting gut health
• What are the direct uses of micro-organisms as food?

  • Cyanobacteria: Black moss, Spirulina (rich in proteins and nutrients)
  • Algae: Nori (seaweed), Chlorella (high in proteins, vitamins, and minerals)
  • Fungi: Quorn (mycoprotein from Fusarium venenatum mold, high in protein and fiber, low in fat)
• What is the conclusion regarding the importance of micro-organisms in food?


  • Crucial roles in food production: fermentation for preservation and flavor development
  • Nutritional enhancement through probiotics
  • Direct food sources high in nutrients
  • Key for food science and nutrition
  • Continued research may lead to new applications and improved food products
• What is the significance of responsible use of micro-organisms in food?


  Ensures food safety and quality
• What are the open-ended questions related to micro-organisms in food?


  1. Explain the process of fermentation and its importance in food preservation and flavor development.
  2. Describe the differences between bacteria, fungi, and algae in terms of their structure and roles in food production.
  3. Discuss the potential future applications of micro-organisms in food science and how they might contribute to addressing global nutritional challenges.