Title: Gram-negative bacterial isolates from fresh-cut processing plants enhance the presence of Escherichia Coli O157:H7 in dual-species biofilms Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 29, 2012
Publication Date: October 18, 2012
Citation: Liu, N., Nou, X., Lefcourt, A.M., Bauchan, G.R., Lo, Y. 2012. Gram-negative bacterial isolates from fresh-cut processing plants enhance the presence of Escherichia Coli O157:H7 in dual-species biofilms. [abstract]. Technical Abstract: Biofilms formed by resident microflora may provide a microenvironment for foodborne bacterial pathogens to survive and cause cross-contamination in fresh-cut processing and handling facilities. The objective of this study is to determine the impact of individual bacteria strains isolated from two local fresh-cut processing plants on the presence of laboratory E. coli O157:H7 strain in dual-species biofilms. Fourteen strains isolated from food contact and non-food contact surfaces, including 4 soil, 7 phytobacterial and 3 phytopathogenic bacterial strains, were cultured to form biofilms with E. coli O157:H7 strains. The total biomass of dual-species biofilms was compared to the monocultural biofilm of both strains in the combination. Three bacteria strains, belonged to Alpha and Beta Proteobacteria, exhibited the synergistic interactions with E. coli O157:H7 in dual-species biofilm formation. Results acquired from this study showed that common phytobacteria, such as Pseudomonas fluorescens and Rhanella aquatilis, did not significantly affect E. coli O157:H7 existence in dual-species biofilms. In contrast, two Gram-negative phytopathogenic bacteria, Burkholderia caryophylli and Rhizobium radiobacter, were able to promote the presence of E. coli O157:H7 with a total increase of 1.0 and 0.33 log CFU/cm2 compared to its monoculture biofilm. Moreover, one soil bacterium, Ralstonia insidiosa, was found to enhance E. coli O157:H7 presence in dual-species biofilms. The ability of Gram-negative bacteria in fresh-cut processing environment to assist the survival of E. coli O157:H7 in dual-species boifilms calls for the development of novel intervention strategies to minimize produce-harbored foodborne illnesses.