Enhancing detection of Listeria monocytogenes in food products using an enzyme

Authors: FELTON, SAMANTHA - University Of Virginia; Armstrong, Cheryl; Chen, Chinyi; He, Yiping; Lee, Joseph - Joe; Reed, Sue; AKULA, NIKKI - University Of Virginia; WALKER, SHARON - Drexel University; BERGER, BRYAN - University Of Virginia; Capobianco, Joseph

Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/9/2022
Publication Date: 10/13/2022
Citation: Felton, S., Armstrong, C.M., Chen, C., He, Y., Lee, J., Reed, S.A., Akula, N., Walker, S., Berger, B., Capobianco Jr, J.A. 2022. Enhancing detection of Listeria monocytogenes in food products using an enzyme. Food Control. https://doi.org/10.1016/j.foodcont.2022.109445.
DOI: https://doi.org/10.1016/j.foodcont.2022.109445

Interpretive Summary: There is a need to identify the presence of microorganisms, in particular human pathogens, in food processing facilities and products. For detection assays to successfully identify the presence of microbial contaminates the adhesive forces between the bacteria biomarkers and the food/contact surface must be overcome to ensure the pathogen or biomarker is transferred to the downstream detection platform. Currently, most standard operating procedures utilize mechanical agitation of the solid phase of a suspension to facilitate separation, and include microbial enrichment to increase the concentration of the pathogen in the liquid phase. The mechanical separation, typically stomaching or hand massaging, can dislodge microorganisms from surfaces. More aggressive approaches can facilitate separation however they also fragment the sample, which can lead to subsequent reattachment of the microorganism and an increase in particulates that can adversely affect detection results. The addition of the enzyme known as CAase demonstrated the ability to separate the pathogen from the surface, which helped improve detection of the microorganism within a current standard operating procedure used by USDA Food Safety and Inspection Service. The work supports the use of the CAase enzyme to improve the accuracy, speed, reliability, and repeatability of pathogen detection protocols.

Technical Abstract: There is a need to identify the presence of microorganisms, in particular human pathogens, in food processing facilities and products. Adhesion of pathogens to surfaces poses a detection challenge with biofilms greatly hindering detection by precluding the transfer of specific material to downstream sensors. Enzymes that disrupt biofilms can therefore enhance detection of foodborne pathogens through facilitating their release from abiotic and biotic surfaces. In this study, a recombinant enzyme, CAase, was applied to improve detection of biofilm-embedded Listeria monocytogenes on food and food contact surfaces. Microbiological and molecular detection methods demonstrated that biofilms treated with enzyme for longer than 4 hours resulted in a significant increase in the number of cells released into the media compared to untreated controls. This work demonstrates the benefits of inclusion of enzymes and biosurfactants within sample processing and detection protocols because of their ability to contribute to a more rapid, accurate, reliable, and repeatable microbial detection assay when biofilm embedded pathogens are present.