Patrick M. Hutchins, PhD
By Patrick M. Hutchins, PhD – Global Product Manager, TSI Inc.
For many decades the only practical metric of airborne microbial contamination has been the colony forming unit (cfu). Adapting growth-based approaches for monitoring modern aseptic manufacturing processes has sometimes proven difficult. Although microbiologists have bemoaned the limitations of measuring only cfu, no alternative metric or technique has yet been adopted. In this article we will review one such alternative microbiological method, commonly called laser induced fluorescence (LIF). For years LIF has played non-compliance-based roles in microbial detection such as root cause investigation and even military treat detection. In aseptic manufacturing LIF shows potential to replace growth-based methods in certain manufacturing paradigms, e.g. highly-automated, near-continuous processes. Here, we will review the fundamentals of LIF microbial detection, it’s benefits with respect to current methods, applications in aseptic manufacturing, and finally the regulatory outlook on LIF.