How do you investigate and respond to a contamination event?

Contamination investigation follows a systematic approach. Immediate response: isolate affected batches, preserve samples for analysis, and implement containment measures. Investigation: identify contaminating organism (microscopy, biochemical tests, molecular identification), determine contamination source (raw materials, equipment, environment, personnel), review environmental monitoring data, and trace activities and deviations. Root cause analysis uses tools like fishbone diagrams or 5-whys. Corrective actions address root cause: enhanced cleaning/sanitization, equipment repairs, procedure revisions, retraining. Preventive actions: improved monitoring, design changes, risk reassessment. Documentation includes investigation report, CAPA records, and impact assessment. Regulatory notification may be required depending on product and severity.