Biofilm detection in the food industry: Challenges in identifying biofilm eps markers and analytical techniques with insights for Listeria monocytogenes

Abstract

Extracellular polymeric substances (EPS) in biofilms are promising targets for eradicating biofilms and monitoring their presence, especially in the food industry. For this understanding, the composition of the EPS matrix is crucial. Ideally, a biofilm marker is found serving both purposes, but such a compound has not yet been discovered. This review aims to identify general biofilm EPS markers distinct from planktonic cells, focusing on macromolecules in the EPS matrix. It also evaluates the feasibility of this goal across different bacterial groups and environmental conditions and discusses EPS analysis methods. This review digs deeper into the EPS matrix starting with an introduction to the EPS matrix itself and describing some of its influencing factors. Next, a brief description of cell-to-cell communication within biofilms is provided, as these interactions significantly influence the EPS matrix. The main part of this review describes the macromolecules inside the EPS matrix and attempts to find biofilm EPS markers applied to bacteria in general and specifically to Listeria monocytogenes as biofilms are a major contributor to its persistence. The last part of the review focuses on the analytical techniques available to characterize the EPS matrix. The review revealed that although multiple candidates showed great potential as biofilm markers, none were unique but ubiquitous in all bacteria tested. To achieve easy biofilm detection with current techniques, it's necessary to identify markers specific to the environmental conditions and common bacterial groups within each food category, sector, or facility, due to the lack of standardization in these techniques. This tailored approach ensures more accurate and effective biofilm monitoring. Moreover, the lack of standardized analytical techniques, including quantification techniques, complexifies studying the EPS matrix and developing monitoring and intervention strategies. Optimizing analytical techniques is crucial for this tailored approach, as it requires refined methods for detection, characterization, and quantification. This ensures the accurate identification of biofilm markers specific to environmental conditions and bacterial groups within each food sector.