physical growth

• What methods did early civilizations use to control microbial growth?

  Salting, smoking, pickling, drying, sunlight
• Why were spices used in cooking historically?

  To mask the taste of spoiled food
• Who contributed to the development of aseptic techniques in the mid-1800s?

  Semmelweiss and Lister
• What was the death rate from nosocomial infections before aseptic techniques?

  10%
• What percentage of mothers died due to infection in hospitals before aseptic techniques?

  25%
• What is sterilization?

  Killing or removing all microbial life
• What is the most commonly used method of sterilization?

  Heating
• What is commercial sterilization?

  Heat treatment that kills Clostridium botulinum endospores
• What does commercial sterilization not kill?

  Endospores of thermophiles
• What is disinfection?

  Reducing pathogenic microorganisms to non-disease-causing levels
• What is a disinfectant?

  Applied to inanimate objects
• What is an antiseptic?

  Applied to living tissue
• What is degerming?

  Mechanical removal of most microbes in a limited area
• What is sanitization?

  Use of chemical agents on food-handling equipment
• What does sepsis indicate?

  Bacterial contamination
• What is asepsis?

  Absence of significant contamination
• What are aseptic techniques used for?

  Prevent contamination during surgery and food processing
• What is a bacteriostatic agent?

  Inhibits the growth of bacteria
• What is a germicide?

  Kills certain microorganisms
• What is a bactericide?

  Kills bacteria
• What is a viricide?

  Inactivates viruses
• What is a fungicide?

  Kills fungi
• What is a sporicide?

  Kills bacterial endospores and fungal spores
• How do bacterial populations die when treated?

  They usually die at a constant rate
• What factors influence the effectiveness of antimicrobial treatment?

  Number of microbes, type, environmental influences, exposure time
• How does the number of microbes affect antimicrobial treatment?

  More microbes take longer to eliminate
• Why are endospores difficult to destroy?

  They are highly resistant to treatments
• How do environmental influences affect antimicrobial treatment?

  Organic material can inhibit antimicrobials
• How does time of exposure affect antimicrobial effectiveness?

  Longer exposure increases effectiveness
• What does heat do to microorganisms?

  Kills them by denaturing proteins
• What is the Thermal Death Point (TDP)?

  Lowest temperature to kill all microbes in 10 minutes
• What is the Thermal Death Time (TDT)?

  Minimal time to kill all bacteria at a temperature
• What is Decimal Reduction Time (DRT)?

  Time to kill 90% of bacteria at a temperature
• How does moist heat kill microorganisms?

  By coagulating their proteins
• Why is moist heat more effective than dry heat?

  Moist heat coagulates proteins better
• What is boiling's effect on microorganisms?

  Kills most pathogens in 10 minutes
• What can survive boiling for 30 minutes?

  Hepatitis virus
• How long can endospores survive boiling?

  20 hours or more
• What is required for reliable sterilization with moist heat?

  Temperatures above boiling water
• What is an autoclave?

  Chamber filled with hot steam under pressure