The Removal of Meat Exudate and Escherichia coli from Stainless Steel and Titanium Surfaces with Irregular and Regular Linear Topographies

Bacterial retention and organic fouling on meat preparation surfaces can be influenced by several factors. Surfaces with linear topographies and defined chemistries were used to determine how the orientation of the surface features affected cleaning efficacy. Fine polished (irregular linear) stainless steel (FPSS), titanium coated fine polished (irregular linear) stainless steel (TiFP), and topographically regular, linear titanium coated surfaces (RG) were fouled with Escherichia coli mixed with a meat exudate (which was utilised as a conditioning film). Surfaces were cleaned along or perpendicular to the linear features for one, five, or ten wipes. The bacteria were most easily removed from the titanium coated and regular featured surfaces. The direction of cleaning (along or perpendicular to the surface features) did not influence the amount of bacteria retained, but meat extract was more easily removed from the surfaces when cleaned in the direction along the linear surface features. Following ten cleans, there was no significant difference in the amount of cells or meat exudate retained on the surfaces cleaned in either direction. This study demonstrated that for the E. coli cells, the TiFP and RG surfaces were easiest to clean. However, the direction of the clean was important for the removal of the meat exudate from the surfaces.

The Influence of Surface Topography and Wettability on Escherichia coli Removal from Polymeric Materials in the Presence of a Blood Conditioning Film

The reduction of biofouling and the reduction of cross-contamination in the food industry are important aspects of safety management systems. Polymeric surfaces are used extensively throughout the food production industry and therefore ensuring that effective cleaning regimes are conducted is vital. Throughout this study, the influence of the surface characteristics of three different polymeric surfaces, polytetrafluoroethylene (PTFE), poly(methyl methacrylate) (PMMA) and polyethylene terephthalate (PET), on the removal of Escherichia coli using a wipe clean method utilising 3% sodium hypochlorite was determined. The PTFE surfaces were the roughest and demonstrated the least wettable surface (118.8°), followed by the PMMA (75.2°) and PET surfaces (53.9°). Following cleaning with a 3% sodium hypochlorite solution, bacteria were completely removed from the PTFE surfaces, whilst the PMMA and PET surfaces still had high numbers of bacteria recovered (1.2 × 107 CFU/mL and 6.3 × 107 CFU/mL, respectively). When bacterial suspensions were applied to the surfaces in the presence of a blood conditioning film, cleaning with sodium hypochlorite demonstrated that no bacteria were recovered from the PMMA surface. However, on both the PTFE and PET surfaces, bacteria were recovered at lower concentrations (2.0 × 102 CFU/mL and 1.3 × 103 CFU/mL, respectively). ATP bioluminescence results demonstrated significantly different ATP concentrations on the surfaces when soiled (PTFE: 132 relative light units (RLU), PMMA: 80 RLU and PET: 99 RLU). Following cleaning, both in the presence and absence of a blood conditioning film, all the surfaces were considered clean, producing ATP concentrations in the range of 0–2 RLU. The results generated in this study demonstrated that the presence of a blood conditioning film significantly altered the removal of bacteria from the polymeric surfaces following a standard cleaning regime. Conditioning films which represent the environment where the surface is intended to be used should be a vital part of the test regime to ensure an effective disinfection process.

Uropathogens Preferrentially Interact with Conditioning Film Components on the Surface of Indwelling Ureteral Stents Rather than Stent Material

Despite routine implementation in urology, indwelling ureteral stents pose as a nidus for infection. Conditioning film accumulates on stents, which prime pathogen adhesion, promoting infectious biofilm formation. However, the extent to which conditioning film components play a role in facilitating bacterial adhesion and biofilm formation remains largely unknown. Here, we examined the interaction of previously identified stent-bound conditioning film components (fibrinogen, uromodulin, and albumin) with bacterial uropathogens. Cytoscopically removed stents were incubated with common uropathogens (Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus). Immunofluorescent double staining was performed to study the localization of uropathogens relative to stent-bound conditioning film proteins. Conditioning film components were identified on the external stent surface with some deposition in the inner lumen. Bacteria co-localized with fibrinogen, uromodulin, and albumin, suggesting a potential mechanism for stent-associated infections. Here, we determine strong co-localization between common uropathogenic bacterial species with prominent conditioning film components on ureteral stents. Further functional validation of interactions amongst these uropathogens and conditioning film proteins may enhance clinical management for stent-associated infections and development of improved stent technologies.

Enhancement in Xerostomia Patient Salivary Lubrication Using a Mucoadhesive

Oral lubrication mediated by mucin and protein containing salivary conditioning films (SCFs) with strong water retainability can get impaired due to disease such as xerostomia, that is, a subjective dry mouth feel associated with the changed salivary composition and low salivary flow rate. Aberrant SCFs in xerostomia patient cause difficulties in speech, mastication, and dental erosion while the prescribed artificial saliva is inadequate to solve the complications on a lasting basis. With the growing aging population, it is urgently needed to propose a new strategy to restore oral lubrication. Existing saliva substitutes often overwhelm the aberrant SCFs, generating inadequate relief. Here we demonstrated that the function of aberrant SCFs in a patient with Sjögren syndrome can be boosted through mucin recruitment by a simple mucoadhesive, chitosan-catechol (Chi-C). Chi-C with different conjugation degrees (Chi-C7.6%, Chi-C14.5%, Chi-C22.4%) was obtained by carbodiimide chemistry, which induced a layered structure composed of a rigid bottom and a soft secondary SCF (S-SCF) after reflow of saliva. The higher conjugation degree of Chi-C generates a higher glycosylated S-SCF by mucin recruitment and a lower friction in vitro. The layered S-SCF extends the “relief period” for Sjögren patient saliva over 7-fold, measured on an ex vivo tongue-enamel friction system. Besides lubrication, Chi-C-treated S-SCF reduces dental erosion depths from 125 to 70 μm. Chi-C shows antimicrobial activity against Streptococcus mutans. This research provides a new key insight in restoring the functionality of conditioning film at articulating tissues in living systems.

Dry mouth: saliva substitutes which adsorb and modify existing salivary condition films improve oral lubrication

Objectives The aims of this study are to assess different saliva substitutes for their efficacy to lubricate the oral cavity, and to relate this oral lubrication to the ability of saliva substitutes to adsorb on and change the structure of the existing salivary conditioning film (SCF). Materials and methods Quartz crystal microbalance with dissipation was used to study the capability of saliva substitutes to interact with natural SCF and the ability to change the secondary SCF (S-SCF). A tongue-enamel friction system mimicking xerostomic conditions was used to assess the relief and relief period expected from these substitutes under set circumstances. Results Saliva Orthana spray, Biotène spray and Gum Hydral gel had an immediate effect on a SCF, increasing its structural softness. BioXtra gel, Biotène gel, Gum Hydral gel and Glandosane spray changed the S-SCF by increasing salivary protein adsorption, while others showed no sign of interaction. With respect to relief, only 2 out of the 16 saliva substitutes tested (Saliva Orthana spray and Gum Hydral gel) performed better than water. Overall, relief period correlated positively to structural softness change, whereas a positive correlation was seen between relief and mass adsorption. Conclusions The majority of saliva substitutes did not adsorb on the SCF, thus did not enhance lubrication. Only saliva substitutes containing carrageenan, carboxymethylcellulose, pig gastric mucin, xanthan gum and carbomer performed better in enhancing oral lubrication. Clinical relevance This objective assessment will help clinicians and patients make better choice of saliva substitutes. This study provides a scientific basis for future improvement in saliva substitutes.