Control of contamination in manufacturing MCQs With Answer

Introduction: Contamination control in pharmaceutical manufacturing is a cornerstone of Quality Control and Quality Assurance that ensures drug safety, efficacy, and regulatory compliance. This blog presents targeted MCQs designed for M.Pharm students to deepen understanding of strategies and practices used to prevent particulate and microbial contamination. Topics covered include cleanroom design and classification, HVAC and filtration, personnel gowning, environmental monitoring, cleaning and disinfection, aseptic processing, media fills, and cross-contamination control. Each question emphasizes practical application and regulatory expectations (cGMP, EU GMP, WHO), helping students prepare for examinations and real-world manufacturing challenges by reinforcing concepts essential for maintaining sterility and product integrity.

Q1. What is the primary objective of a contamination control strategy in pharmaceutical manufacturing?

• To reduce manufacturing costs by minimizing maintenance
• To protect product quality and patient safety by preventing particulate and microbial contamination
• To maximize production throughput regardless of environmental conditions
• To eliminate the need for environmental monitoring

Correct Answer: To protect product quality and patient safety by preventing particulate and microbial contamination

Q2. Which cleanroom classification system is commonly used to define airborne particle limits and is referenced in EU GMP and ISO standards?

• GMP Class A/B/C/D
• ISO 14644 cleanroom classification
• USP <797> only
• FDA 21 CFR Part 11

Correct Answer: ISO 14644 cleanroom classification

Q3. In aseptic processing, which area is typically designated as the highest cleanliness zone for direct product contact operations?

• Grade D
• Grade C
• Grade B (or ISO Class 5 zone within Grade A)
• Unclassified support area

Correct Answer: Grade B (or ISO Class 5 zone within Grade A)

Q4. Which type of filter is considered essential in preventing microbial and particulate contamination in cleanroom supply air?

• Bag filter
• Activated carbon filter
• HEPA filter
• Sediment filter

Correct Answer: HEPA filter

Q5. What is the principal reason for maintaining defined pressure differentials between adjacent cleanroom grades?

• To control room temperature precisely
• To ensure laminar flow velocity is maximized
• To prevent flow of less clean air into cleaner zones and reduce cross-contamination
• To reduce energy consumption of HVAC systems

Correct Answer: To prevent flow of less clean air into cleaner zones and reduce cross-contamination

Q6. Which environmental monitoring method is best suited for detecting viable microorganisms in the air of a cleanroom?

• Optical particle counting
• Active air sampling onto culture media (impaction or filtration)
• Temperature logging
• Surface ATP bioluminescence only

Correct Answer: Active air sampling onto culture media (impaction or filtration)

Q7. During personnel gowning for aseptic areas, what is a critical control measure to minimize contamination?

• Wearing street clothes under the gown
• Putting on gloves first and gown last
• Following a validated gowning sequence and performing glove fingertip sampling
• Using personal perfumes to mask odors

Correct Answer: Following a validated gowning sequence and performing glove fingertip sampling

Q8. Which sampling technique is commonly used to assess surface microbial contamination inside a cleanroom?

• Air particle counting
• Surface contact plates (RODAC plates) or swab sampling onto culture media
• Continuous CO2 monitoring
• Visual inspection only

Correct Answer: Surface contact plates (RODAC plates) or swab sampling onto culture media

Q9. What is the main purpose of a media fill (process simulation) in aseptic manufacturing?

• To validate sterility testing methods
• To simulate production using growth medium and demonstrate aseptic process capability
• To train operators on packaging procedures only
• To measure HEPA filter efficiency directly

Correct Answer: To simulate production using growth medium and demonstrate aseptic process capability

Q10. Which cleaning agent class is typically used for routine disinfection of surfaces in sterile manufacturing areas?

• Non-ionic detergents only
• Quaternary ammonium compounds, chlorine-based agents, or hydrogen peroxide-based disinfectants depending on validated efficacy
• Organic solvents for routine surface wiping
• Pure water without disinfectant

Correct Answer: Quaternary ammonium compounds, chlorine-based agents, or hydrogen peroxide-based disinfectants depending on validated efficacy

Q11. Which parameter is most appropriate to monitor for non-viable contamination control in a cleanroom?

• Microbial colony counts from settle plates
• Particle counts using a calibrated optical particle counter
• Swab culture results only
• Humidity alone

Correct Answer: Particle counts using a calibrated optical particle counter

Q12. What is cross-contamination in pharmaceutical manufacturing?

• Intentional blending of two products to save costs
• Unintended contamination of a product with another product, active pharmaceutical ingredient, or residue that may affect quality or safety
• Mixing of sterile and non-sterile cleaning agents
• Transfer of personnel between shifts

Correct Answer: Unintended contamination of a product with another product, active pharmaceutical ingredient, or residue that may affect quality or safety

Q13. Which control reduces contamination risk during material transfer into cleanrooms?

• Using open transfer windows during peak operations
• Implementing airlocks, pass-throughs with decontamination cycles, and validated transfer procedures
• Allowing direct entry of external packaging into production areas
• Skipping incoming material quarantine

Correct Answer: Implementing airlocks, pass-throughs with decontamination cycles, and validated transfer procedures

Q14. Which of the following best describes a hygienic design principle to minimize contamination?

• Complex surfaces with crevices to trap residues
• Materials and equipment selected for cleanability, smooth surfaces, and minimal dead legs
• Use of porous materials for faster drying
• Open piping with inaccessible joints

Correct Answer: Materials and equipment selected for cleanability, smooth surfaces, and minimal dead legs

Q15. What does a Sterility Assurance Level (SAL) of 10^-6 indicate for a sterilization process?

• There is a 100% chance of sterility
• There is one in a million probability of a viable organism surviving the sterilization process on a single item
• The process is ineffective and must be repeated six times
• The sterilization cycle time is reduced by a factor of six

Correct Answer: There is one in a million probability of a viable organism surviving the sterilization process on a single item

Q16. Which validation activity demonstrates that cleaning procedures consistently remove product residues and microorganisms?

• Airflow balancing
• Cleaning validation with worst-case soils, analytical residue limits, and microbiological acceptance criteria
• Operator gowning audits alone
• HEPA filter integrity testing only

Correct Answer: Cleaning validation with worst-case soils, analytical residue limits, and microbiological acceptance criteria

Q17. Which environmental parameter is most critical to control in isolators or RABS used for aseptic filling?

• Sound levels
• Internal pressure, unidirectional airflow and HEPA filtration to maintain aseptic barrier
• Ambient lighting color
• Operator personal devices

Correct Answer: Internal pressure, unidirectional airflow and HEPA filtration to maintain aseptic barrier

Q18. Why is routine microbiological identification of isolates from cleanroom monitoring important?

• It is not necessary if particle counts are low
• To determine trends, root causes, and whether isolates are environmental, human, or process-related
• To replace routine cleaning schedules
• To validate HVAC filters daily

Correct Answer: To determine trends, root causes, and whether isolates are environmental, human, or process-related

Q19. Which procedure is essential before initiating aseptic operations after a scheduled cleaning and disinfection?

• Immediate start without checks to save time
• Allow validated contact time for disinfectants, then perform environmental checks and gowning verification
• Only check surface ATP and ignore culture-based methods
• Open all windows to accelerate drying

Correct Answer: Allow validated contact time for disinfectants, then perform environmental checks and gowning verification

Q20. What is the role of trend analysis in environmental monitoring programs?

• To provide a one-time snapshot without follow-up
• To identify shifts or excursions over time, enabling corrective actions before product impact
• To eliminate the need for personnel training
• To justify removing routine cleaning

Correct Answer: To identify shifts or excursions over time, enabling corrective actions before product impact

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