In a recent study conducted by Pennsylvania State University and published in Microbiome volume 7, 21 August 2019 the researchers showed that a packing facility with a significantly higher Listeria monocytogenes presence had biofilm formation by the Pseudomonadaceae and the fungal family Dipodascaceae that protected the Listeria. The lack of proper drainage, poor cleaning, and sanitation protocols have contributed to the unique microbiota in the built environment of the facility and the biofilm formation. Pseudomonadaceae and Dipodascaceae predominate in the facility and represent microorganisms that are known biofilm formers and indicators of unhygienic conditions, respectively. Biofilm formation may support L. monocytogenes persistence in this facility due to the protection offered by the biofilm. Bacteria such as Pseudomonadaceae may help foodborne pathogen such as L. monocytogenes in survival and persistence in food processing environments and thus increase the food safety and public health risk. @ https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-019-0726-2
Impact of biofilm formation in fruit packaging plants on the survival of L. monocytogenes
Multistate foodborne disease outbreaks and recalls of apples and apple products contaminated with Listeria monocytogenes demonstrate the need for improved pathogen control in the apple supply chain. Apple processing facilities have been identified in the past as potential sources of persisting L. monocytogenes contamination. In this study, we sought to understand the composition of microbiota in built apple and other tree fruit processing environments and its association with the occurrence of the foodborne pathogen L. monocytogenes. Analysis of 117 samples collected from three apple and other tree fruit packing facilities (F1, F2, and F3) showed that facility F2 had a significantly higher L. monocytogenes occurrence compared to F1 and F3 (p < 0.01). The microbiota in facility F2 was distinct compared to facilities F1 and F3 as supported by the mean Shannon index for bacterial and fungal alpha diversities that was significantly lower in F2, compared to F1 and F3 (p < 0.01). Microbiota in F2 was uniquely predominated by bacterial family Pseudomonadaceae and fungal family Dipodascaceae. The composition and diversity of microbiota and mycobiota present in the investigated built food processing environments may be indicative of persistent contamination with L. monocytogenes. These findings support the need for further investigation of the role of the microbial communities in the persistence of L. monocytogenes to support the optimization of L. monocytogenes control strategies in the apple supply chain.