Metal Particle Detection Methods and Their Use for Freeze-Dried Vaccine Inspection: A Review

We establish a set of metal particle detection methods that are suitable for automated inspection of freeze-dried vaccines. We first identify the requirements for freeze-dried vaccine inspection. We then assess metal particle detection methods obtained through a comprehensive literature review with the requirements for automated inspection. In particular, we find inductive sensors, superconducting quantum interference device (SQUID)-based sensors, giant magnetoresistive (GMR)/tunneling magnetoresistive (TMR)-based sensors, and THz imaging, hyperspectral imaging, thermal imaging, X-ray inspection, and radio frequency identification (RFID)-based sensors promising for automated inspection of freeze-dried vaccines. However, experiments assessing the applicability of these methods for freeze-dried vaccine inspection are severely limited, and future research is required to choose the best performing methods.