Expert view: Mitigating risk with modern microbial identifications

Over the last few years, there have been many product recalls associated with fungal contamination. Of these, few had associated species-level IDs, compared with bacterial contamination recalls of which most had a species ID.

In the past, microbiologists may have been limited in their ability to provide an accurate species-level ID. Even now, many quality control (QC) labs still use macroscopy and microscopy to identify any fungal isolates from their facilities. With the complexity of their microscopic structures, it is no wonder that fungal ID using this technique requires training and years of experience and remains unreliable.

There are commercial systems available to aid in fungal ID but often these are limited by the technology itself
(eg, phenotypic systems have long been recognised as less accurate and precise than genotypic systems by the US Food and Drug Administration [FDA]). In recent years, MALDI-TOF has become increasingly commonplace as it provides a reliable method for identifying microorganisms. However, all ID systems rely on a library that is used to compare the result and generate the ID. If something is not in that library, there may be no ID or, perhaps even worse, an incorrect ID and subsequent incorrect assessment of risk. This seems to be an area often overlooked; yet it should be evaluated per USP (1113) and EP (5.1.6) guidance.

While some microbiologists might see newer technologies as a loss of skills, but the real skill does not come from generating the ID; it comes from understanding the impact that the species will have on their production process or product. This knowledge adds real impact and allows for proactive decision making. This not only ensures patient safety but also adds financial benefits to the manufacturer through prevention of interventions or batch scrappage.