Management of mix-ups and cross-contamination MCQs With Answer

Introduction: Effective management of mix-ups and cross-contamination is critical in pharmaceutical manufacturing to ensure patient safety, product quality, and regulatory compliance. This blog presents focused MCQs on identifying root causes, preventive controls, investigative steps, cleaning validation, segregation, and containment strategies used to manage mix-ups and cross-contamination. Questions cover risk assessment techniques, sampling and swab strategies, personnel and material flow, labeling practices, batch sequencing, and corrective and preventive actions (CAPA). These items are designed to reinforce conceptual understanding and practical application for M.Pharm students preparing for exams or workplace responsibilities in Quality Control & Quality Assurance.

Q1. What is the most appropriate initial action when a suspected mix-up between two finished product batches is discovered?

• Continue release testing and report after release
• Quarantine both affected batches and secure all associated materials and documentation
• Discard one batch immediately to avoid delays
• Inform marketing department to update stakeholders

Correct Answer: Quarantine both affected batches and secure all associated materials and documentation

Q2. Which of the following is the primary objective of cleaning validation in preventing cross-contamination?

• To prove cleaning agents remove all microbial contamination
• To demonstrate that carryover residues are reduced to acceptable levels and do not contaminate subsequent products
• To document the time taken for cleaning procedures
• To ensure operators follow cleaning checklists

Correct Answer: To demonstrate that carryover residues are reduced to acceptable levels and do not contaminate subsequent products

Q3. In a risk-based approach to prevent mix-ups, which factor is considered most critical for determining control measures?

• Cost of implementing controls
• Therapeutic index and toxicity of product components
• Availability of spare equipment
• Marketing priorities

Correct Answer: Therapeutic index and toxicity of product components

Q4. Which documentation practice most effectively reduces the probability of mix-ups during manufacturing?

• Using handwritten batch records without revision history
• Implementing barcode or electronic verification systems for materials and labels
• Relying on verbal confirmations between operators
• Keeping duplicate sets of labels in a common drawer

Correct Answer: Implementing barcode or electronic verification systems for materials and labels

Q5. Which environmental control is critical to minimize airborne cross-contamination in aseptic or high-risk zones?

• Low lighting to reduce operator fatigue
• Proper differential pressure, HEPA filtration, and airflow patterns (unidirectional flow)
• Open windows for natural ventilation
• Periodic fumigation without HEPA filters

Correct Answer: Proper differential pressure, HEPA filtration, and airflow patterns (unidirectional flow)

Q6. When investigating a cross-contamination event, what is the most informative first step in root cause analysis?

• Immediately firing the operator on duty
• Collecting and reviewing batch records, cleaning logs, and personnel movement data
• Repeating the entire production run
• Changing all cleaning agents used in the facility

Correct Answer: Collecting and reviewing batch records, cleaning logs, and personnel movement data

Q7. Which approach is best for controlling potent or highly toxic compounds to prevent cross-contamination?

• Using the same equipment with longer cleaning cycles
• Designating dedicated equipment, containment, and segregated areas for potent compounds
• Producing potent compounds only during off-hours
• Reducing operator training to avoid confusion

Correct Answer: Designating dedicated equipment, containment, and segregated areas for potent compounds

Q8. In cleaning validation, which acceptance criterion is commonly used for carryover limits?

• Visual cleanliness only
• Limit based on 1/1000th of the minimum therapeutic dose or toxicological safety limits (health-based limits)
• Zero residue detection regardless of toxicity
• Arbitrary limits set by production staff

Correct Answer: Limit based on 1/1000th of the minimum therapeutic dose or toxicological safety limits (health-based limits)

Q9. What is the best practice for batch sequencing to reduce risk of cross-contamination?

• Producing products in alphabetical order
• Sequencing from non-potent to potent and from least to most toxic, with appropriate cleans between families
• Running the most toxic products first at the start of the day only
• Random sequencing to maximize flexibility

Correct Answer: Sequencing from non-potent to potent and from least to most toxic, with appropriate cleans between families

Q10. Which monitoring technique is most appropriate for verifying surface cleanliness after cleaning in contamination investigations?

• Environmental temperature logging
• Surface swab sampling with validated analytical method
• Counting operator footsteps near equipment
• Checking inventory records

Correct Answer: Surface swab sampling with validated analytical method

Q11. Which personnel practice most reduces the risk of cross-contamination between manufacturing areas?

• Allowing operators to wear the same gown between production zones
• Establishing clear personnel flow, dedicated gowning, and restricted access between areas
• Rotating personnel frequently between different product lines
• Using casual clothing under protective garments

Correct Answer: Establishing clear personnel flow, dedicated gowning, and restricted access between areas

Q12. How should a company treat raw material labels to prevent mix-ups during issuance?

• Labels can be hand-copied to save time
• Use unique identifiers, barcodes, and issue controls with reconciliation before use
• Store all labels together regardless of material
• Remove supplier information to avoid bias

Correct Answer: Use unique identifiers, barcodes, and issue controls with reconciliation before use

Q13. Which corrective action is most appropriate after confirming a cross-contamination event that reached the finished product?

• Destroy affected product, conduct risk assessment, notify regulatory authorities as required, and implement CAPA
• Attempt to rework the product without documentation
• Reschedule marketing to minimize visible impact
• Rely on visual inspection to clear the product

Correct Answer: Destroy affected product, conduct risk assessment, notify regulatory authorities as required, and implement CAPA

Q14. Which factor is least likely to contribute directly to physical mix-ups?

• Poor label design and similar packaging
• Inadequate change control during formulation changes
• Clear segregation and dedicated storage
• Insufficient training of material handlers

Correct Answer: Clear segregation and dedicated storage

Q15. For allergen control to prevent cross-contact, what combination is most effective?

• Relying solely on ingredient supplier statements
• Dedicated lines for allergen-containing products, validated cleaning, and strict labeling
• Rotating allergen and non-allergen production without cleaning
• Random visual inspections

Correct Answer: Dedicated lines for allergen-containing products, validated cleaning, and strict labeling

Q16. What is the role of an immediate containment action when a suspected mix-up is found on the line?

• To ensure product release without delay
• To stop production, secure suspect materials, prevent further use, and protect unaffected batches
• To reassign operators to different tasks
• To increase production speed to compensate

Correct Answer: To stop production, secure suspect materials, prevent further use, and protect unaffected batches

Q17. Which validation element is essential when introducing a new cleaning agent to reduce cross-contamination?

• Only operator preference testing
• Compatibility testing with residues, materials, and analytical recovery studies (cleaning validation studies)
• Changing cleaning times without testing
• Using the new agent in production immediately for cost reasons

Correct Answer: Compatibility testing with residues, materials, and analytical recovery studies (cleaning validation studies)

Q18. When performing a risk assessment for cross-contamination, which tool is commonly used to prioritize risks?

• Simple random sampling
• Failure Mode and Effects Analysis (FMEA) or HACCP-based approaches
• Inventory turnover ratios
• Marketing demand forecasts

Correct Answer: Failure Mode and Effects Analysis (FMEA) or HACCP-based approaches

Q19. How often should cleaning validation be re-evaluated to ensure ongoing control of cross-contamination?

• Never, once validated it is permanent
• Whenever there are process, product, equipment, or cleaning changes and periodically as part of GMP review
• Only when auditors request it
• Every ten years by default

Correct Answer: Whenever there are process, product, equipment, or cleaning changes and periodically as part of GMP review

Q20. Which monitoring program provides ongoing assurance that cross-contamination controls remain effective in manufacturing areas?

• One-time vendor audits
• Routine environmental monitoring, surface swabs, personnel monitoring, and trend analysis
• Annual cleaning without records
• Marketing surveys

Correct Answer: Routine environmental monitoring, surface swabs, personnel monitoring, and trend analysis

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