Q.: What is Sterilization?
· Process of destroying all microbial life, including fungi, viruses, and spores· Uses chemical & physical methods· Types: o Physical Methods: Heating, Radiation, Filtrationo Chemical Methods: Gaseous sterilization (Formaldehyde, Ethylene oxide, Methanol)
Q.: Physical Methods of Sterilization
· Dry Heat Sterilization (160°C-180°C for 1.5 hrs) – Hot air oven, Flaming· Moist Heat Sterilization (121°C-134°C under 15 lbs pressure for 20 min) – Autoclave· Radiation (UV rays, Gamma rays) – Used for heat-sensitive products· Filtration – Removal of microbes (e.g., 0.22-micron cellulose filter)
Q.: Laminar Air Flow (LAF)
· Principle: Continuous parallel flow of sterile air through filters· Working: o Air passes through a HEPA filtero Removes airborne contaminationo Maintains sterile conditions· HEPA Filter: Removes 99.97% of contaminants (0.3 um)· ULPA Filter: Removes 99.999% of contaminants (0.12 um)
Q: Gram Staining & Bacterial Differentiation
· Principle: Differentiates bacteria based on cell wall composition· Procedure: Uses crystal violet, iodine, alcohol, safranin· Examples: o Gram-Positive: Bacillus subtilis, Lactobacillus, Staphylococcuso Gram-Negative: E. coli, Salmonella, Pseudomonas
Q.: Bacterial & Fungal Spore Staining
· Bacterial Spore Staining: Schaeffer-Fulton method (Malachite green)· Fungal Spore Staining: Lactophenol Cotton Blue (LPCB) o Phenol kills organismso Lactic acid preserves structureo Cotton blue stains fungal cell wall
Q.: What is Disinfection?
· Process of killing microbial life (except bacterial spores)· Used for surfaces, pharmaceutical instruments· Common Disinfectant: 70% Isopropyl Alcohol (IPA)
Q.: Why Use 70% IPA Instead of 100%?
· Mode of Action: Protein coagulation at a slow rate· Penetration: 70% IPA penetrates microbial cells effectively· Evaporation: Slower, ensuring longer contact time for disinfection
Q.: Antiseptics
· Definition: Chemical agents used to destroy pathogens on skin or wounds· Examples: Sanitizers, Hydrogen Peroxide, Iodine (Tincture of Iodine)
Q.: Water Analysis & Bioburden Testing
· MPN (Most Probable Number): Detects coliforms in water· MLT (Microbial Limit Test): Determines microbial load· CFU (Colony Forming Unit): Estimates viable bacteria/fungi in a sample· Bioburden Testing: Determines total viable microbes in pharmaceutical products
Q.: Environmental Monitoring in Pharma
· Methods: 1. Settle Plate Method2. Contact Plate Method3. Swab Testing4. Air Sampler (Instrument)5. Personnel Monitoring· SCDA (Soybean Casein Digest Agar): Used for bacterial & fungal growth monitoring
Q.: Microbiology Pioneers
· Father of Microbiology: Antonie van Leeuwenhoek· Father of Modern Microbiology: Louis Pasteur
Happy Learning
Reference:https://www.linkedin.com/posts/vikas-bedi-37a42117b_microbiology-interview-questions-and-answers-ugcPost-7304665547189710848-9Ja9/?utm_source=share&utm_medium=member_ios&rcm=ACoAADUYKSkBX2GkEqxcuZW4TLku99jKP02MA8Y