Process Validation – Sterilization MCQs With Answer

Process Validation – Sterilization MCQs With Answer

Introduction: This quiz collection focuses on sterilization process validation topics essential for M.Pharm students enrolled in MIP 202T – Scale Up & Technology Transfer. The questions cover fundamental concepts such as sterility assurance level (SAL), D- and z-values, F0 lethality, biological indicators, steam penetration tests (Bowie‑Dick), sterilization modalities (moist heat, dry heat, ethylene oxide, radiation, membrane filtration), and protocol stages (IQ/OQ/PQ). Emphasis is placed on practical validation strategies, worst-case selection, overkill approach, parametric release, and requalification triggers. These MCQs are designed to deepen understanding and prepare students for exam and industry application in sterile manufacturing and technology transfer.

Q1. What does the Sterility Assurance Level (SAL) of 10^-6 mean in sterilization?

• Probability of survival of 1 microorganism per batch
• Probability that one unit is non‑sterile is 1 in 1,000
• Probability that one unit is non‑sterile is 1 in 1,000,000
• Reduction of microbial population by 6 logs during sterilization

Correct Answer: Probability that one unit is non‑sterile is 1 in 1,000,000

Q2. Which biological indicator organism is typically used to validate steam (moist heat) sterilization?

• Bacillus atrophaeus
• Geobacillus stearothermophilus
• Clostridium difficile
• Escherichia coli

Correct Answer: Geobacillus stearothermophilus

Q3. What is the definition of a D‑value in sterilization microbiology?

• Temperature increase required to reduce D‑value by tenfold
• Time required at a given condition to reduce the microbial population by one log (90%)
• Total time required to achieve sterilization at any temperature
• Number of survivors after sterilization

Correct Answer: Time required at a given condition to reduce the microbial population by one log (90%)

Q4. What does the z‑value represent in thermal sterilization kinetics?

• Time to achieve a 6‑log reduction at reference temperature
• Temperature change needed to change the D‑value by a factor of ten
• Decimal reduction of spores per minute
• The heat penetration index for a product

Correct Answer: Temperature change needed to change the D‑value by a factor of ten

Q5. The F0 value is defined as:

• The number of minutes at 121.1°C required to achieve specified lethality relative to reference D‑value
• Temperature equivalent to 100°C for moist heat sterilization
• Time required for air removal from a sterilizer
• The minimum exposure time for ethylene oxide sterilization

Correct Answer: The number of minutes at 121.1°C required to achieve specified lethality relative to reference D‑value

Q6. What is the primary purpose of the Bowie‑Dick test in steam sterilization?

• To verify steam temperature stability during the cycle
• To detect presence of non‑condensable gases and inadequate air removal in a prevacuum steam sterilizer
• To measure biological indicator performance
• To confirm aeration effectiveness after ethylene oxide sterilization

Correct Answer: To detect presence of non‑condensable gases and inadequate air removal in a prevacuum steam sterilizer

Q7. In validation practice, what is the “overkill” approach?

• Selecting the shortest possible cycle that just meets SAL for routine use
• Selecting a cycle that sterilizes only the most sensitive product components
• Selecting a cycle that provides a very large margin of microbial reduction (e.g., ≥12‑log) over the challenge organism
• Using biological indicators at random locations to estimate lethality

Correct Answer: Selecting a cycle that provides a very large margin of microbial reduction (e.g., ≥12‑log) over the challenge organism

Q8. Which biological indicator organism is commonly used for ethylene oxide and dry heat sterilization validation?

• Geobacillus stearothermophilus
• Staphylococcus aureus
• Bacillus atrophaeus
• Pseudomonas aeruginosa

Correct Answer: Bacillus atrophaeus

Q9. What are the typical units used to express a D‑value?

• Degrees Celsius (°C)
• Percentage kill per minute
• Minutes
• Log reductions

Correct Answer: Minutes

Q10. Which stage of sterilization validation confirms that the process performs effectively under routine production conditions with actual product loads?

• Installation Qualification (IQ)
• Operational Qualification (OQ)
• Performance Qualification (PQ)
• Design Qualification (DQ)

Correct Answer: Performance Qualification (PQ)

Q11. What is the main purpose of the aeration step after ethylene oxide sterilization?

• To inactivate biological indicators used during sterilization
• To cool the products to room temperature
• To remove residual ethylene oxide and by‑products to acceptable safety levels
• To dry the product after a moist sterilization cycle

Correct Answer: To remove residual ethylene oxide and by‑products to acceptable safety levels

Q12. For sterilizing sterile pharmaceutical solutions by filtration, which membrane pore size is generally used to remove bacteria?

• 0.8 μm
• 0.45 μm
• 0.22 μm
• 0.1 μm

Correct Answer: 0.22 μm

Q13. Which radiation source is most commonly used in commercial gamma sterilization?

• Electron beam from linear accelerator
• Ultraviolet lamp
• Cobalt‑60 gamma source
• X‑ray generator

Correct Answer: Cobalt‑60 gamma source

Q14. If a sterilization process reports an F0 = 8, this means:

• The process delivered the equivalent lethality of 8 minutes at 121.1°C
• The process ran for 8 cycles
• The process achieved an 8‑log reduction
• The process temperature was 8°C above reference

Correct Answer: The process delivered the equivalent lethality of 8 minutes at 121.1°C

Q15. At approximately what incubation temperature are Geobacillus stearothermophilus biological indicators normally cultured after steam sterilization challenge?

• 37°C
• 55–60°C
• 25°C
• 4°C

Correct Answer: 55–60°C

Q16. Which characteristic makes Geobacillus stearothermophilus spores suitable as steam sterilization indicators?

• They are heat‑sensitive and grow at low temperatures
• They form biofilms that resist steam
• They produce enzymes that neutralize steam lethality
• They are highly resistant spores to moist heat, providing a conservative challenge

Correct Answer: They are highly resistant spores to moist heat, providing a conservative challenge

Q17. How is Sterility Assurance Level (SAL) best described?

• A measure of the chemical residue remaining after sterilization
• The probability of a viable microorganism being present on a sterilized unit
• A time‑temperature profile for sterilization cycles
• The number of biological indicators used in validation

Correct Answer: The probability of a viable microorganism being present on a sterilized unit

Q18. What is the purpose of load mapping during performance qualification of a steam sterilizer?

• To track operator training records
• To determine the most economical cycle time
• To identify locations within the load that receive minimum lethality and ensure adequate steam penetration
• To measure EO residuals across different packaging materials

Correct Answer: To identify locations within the load that receive minimum lethality and ensure adequate steam penetration

Q19. When is revalidation of a sterilization process required?

• Only once after initial validation and never again
• Only when biological indicator failures occur
• After significant changes to product, process, equipment or periodically (e.g., annually) according to procedure
• Only if the regulatory agency requests it

Correct Answer: After significant changes to product, process, equipment or periodically (e.g., annually) according to procedure

Q20. What does parametric release mean for terminally sterilized products?

• Releasing product based solely on end‑product sterility testing
• Releasing product based on validated process parameters and documentation rather than routine sterility testing of each batch
• Releasing product before completion of sterilization cycle
• Releasing product only after extended incubation of biological indicators

Correct Answer: Releasing product based on validated process parameters and documentation rather than routine sterility testing of each batch

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