Short Communication Attachment of Bacterial Pathogens to a Bacterial Cellulose–Derived Plant Cell Wall Model: A Proof of Concept Michelle S.F. Tan, Yi Wang, and Gary A. Dykes Abstract This study aimed to establish, as a proof of concept, whether bacterial cellulose (BC)–derived plant cell wall models could be used to investigate foodborne bacterial pathogen attachment. Attachment of two strains each of Salmonella enterica and Listeria monocytogenes to four BC–derived plant cell wall models (namely, BC, BC-pectin [BCP], BC-xyloglucan [BCX], and BC-pectin-xyloglucan [BCPX]) was investigated. Chemical analysis indicated that the BCPX composite (31% cellulose, 45.6% pectin, 23.4% xyloglucan) had a composition typical of plant cell walls. The Salmonella strains attached in significantly ( p < 0.05) higher numbers ( *6 log colony-forming units [CFU]/cm 2 ) to the composites than the Listeria strains (*5 log CFU/cm 2 ). Strain-specific differences were also apparent with one Salmonella strain, for example, attaching in significantly ( p < 0.05) higher numbers to the BCX composite than to the other composites. This study highlights the potential usefulness of these composites to understand attachment of foodborne bacteria to fresh produce. Introduction M inimally processed fresh produce is a major source of microbial foodborne disease worldwide. Under- standing and preventing the attachment of foodborne patho- gens to fresh produce may provide a means to control this disease (Aruscavage et al., 2006; Saggers et al., 2008). Plant cell wall (PCW) components, such as pectin, may provide receptor sites for bacteria, particularly in the case of cut surfaces of produce (Saggers et al., 2008). The inability to manipulate native PCWs have made studies investigating bacterial attachment to plants difficult (Aruscavage et al., 2006; Saggers et al., 2008). A bacterial cellulose (BC)–derived PCW model, which has characteristics similar to Type I PCWs, has been used to study cell wall organization, structure, and chemistry (Cybulska et al., 2011). This study aimed to establish, as a proof of concept, whether BC-derived PCW models could be used to investigate foodborne bacterial pathogen attachment. This study investigated the role of cellulose, pectin, and xyloglucan on the attachment of Salmonella enterica and Listeria mono- cytogenes, which are important human pathogens commonly associated with fresh-cut produce. Materials and Methods Salmonella Enteritidis ATCC 13076, Salmonella Typhimur- ium ATCC 10428, and Listeria monocytogenes ATCC 7644 from the American Type Culture Collection (Manassas, VA) and Listeria monocytogenes B2 from our laboratory were used. Cultures were grown in tryptic soy broth for 24 h (Salmo- nella) or 48h (Listeria) at 37°C, centrifuged (5478 · g, 10 min) and resuspended in phosphate-buffered saline (PBS) pH 7.4 (1 st BASE, Singapore) at *10 6 colony-forming units (CFU)/mL. Four PCW composites (namely, BC, BC-pectin [BCP], BC- xyloglucan [BCX], and BC-pectin-xyloglucan [BCPX]) were produced (Cybulska et al., 2011). Gluconacetobacter xylinus ATCC 53524 was grown in 10 mL Hestrin and Schramm (HS) broth at 25°C (Hestrin and Schramm, 1954), and 0.1 mL of this inoculum was added to 3 mL of HS medium with or without combinations of pectin (apple pectin Classic AU 710 DM 30%; Herbstreith and Fox, Germany) and/or xyloglucan (Glyloid 3S; Dainippon, Japan) in enclosed plastic containers (1.5 · 1.5 · 1.5 cm). Self-assembled PCW films (1.5 cm · 1.5 cm, *2 mm thickness) were harvested after 72 h of static growth at 25°C. The chemical composition of the films were analyzed using gas–liquid chromatography and an uronic acid colori- metric assay (Mikkelsen et al., 2011). Composites were rinsed in 6 mM CaCl 2 at 100 rpm for 1 h using a Lab Companion SK-600 benchtop shaker (Medline, UK) to remove media components. For attachment assays, composites were immersed in 300-mL bacterial suspensions (10 6 CFU/mL) with shaking at 100 rpm at room temperature for 5 s, 30 s, 1 min, 3 min, 5 min, 10 min, or 20 min. Numbers of School of Science, Monash University, Selangor, Malaysia. FOODBORNE PATHOGENS AND DISEASE Volume 10, Number 11, 2013 ª Mary Ann Liebert, Inc. DOI: 10.1089/fpd.2013.1536 992