First, don't ask what type of contamination! It is irrelevant since the interviewer wants to know if you have experience dealing with contamination (most laboratory professionals do) and how you controlled it. Reflect on a time when you dealt with contamination in the lab. If you are early in your career, then think about your experience with this as a student and what you might have learned from instructors and other professionals.

It is best to explain that if contamination is detected in your laboratory, the first step would be to pinpoint the source of the issue. Describe how you would carefully review laboratory procedures, equipment, and materials used during the testing process to identify any potential sources of contamination. From there, you would take swift action to eliminate or reduce the contamination. This could involve cleaning and disinfecting equipment, removing contaminated materials, or adjusting your testing procedures to prevent future contamination. Then explain how you would also conduct a thorough review of the quality control processes to ensure they are effective in detecting any potential contamination in the future.