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Bakery food contact surfaces generally include conveyor belts where the foodstuff is in contact with surfaces for long periods. The aim of the study was to analyse biofilm levels of B. cereus by initially inoculated vegetative cells and spores on different polyurethane conveyor belts. The overall biomass of the biofilm was measured using the optical density of absorbed crystal violet dye in cells. Moreover, the efficacy of cleaning agents, ultrasound, and a combined method was tested. The results show biofilm inoculated from spores attaches to surfaces the most firmly, followed by wild and standard strains. We did not prove that material roughness or contact angle impact the overall biomass of the biofilm. Furthermore, an efficacy assessment shows that strongly attached biofilm from spores is more difficult to eliminate in comparison to biofilm from vegetative cells. Moreover, we determined that using either the cleaning agent or ultrasound had limited capacity for biofilm removal in comparison with the combined method. Therefore, prevention of food contamination should also include hygiene management of food contact materials. The bakery industry should plan to change cleaning procedures to those implementing hurdle technologies. [ABSTRACT FROM AUTHOR]

The fourth principle of Green Chemistry, a critically important area of sustainability science, identifies that substances should maintain intended functions while possessing limited intrinsic hazards to public health and the environment. In the present study, we empirically determined efficacy of 20 cleaning products against E. coli attachment to surfaces. Subsequently, probabilistic assessments using novel chemical efficacy distributions (CEDs) were conducted. Results for most chemicals indicated bacterial detachment with increasing concentration. Using a threshold concentration of 5th centiles, these cleaning product ingredients were predicted to detach E. coli (Lowest Observable Effect Concentration) at or below 0.7 (0.2, 2.2) mg L−1 for 5% of ingredients. We then employed chemical toxicity distributions (CTDs) to examine acute toxicity, based on currently available information, for common mammalian models. Results demonstrate that probabilities of associated hazards for rat (oral exposure route), mouse (oral exposure route), rabbit (dermal exposure route), and rat (inhalation exposure route) were 43.2%, 36.7%, 38.6% and 75.5%, respectively. A novel joint probability distribution analysis approach was then developed and applied to identify substances with various efficacy (CED) and hazard (CTD) characteristics. Our observations indicate that combining efficacy and toxicity information using joint probability curves may be useful for identifying classes of antimicrobial products, and other chemical classes, to optimize efficacy while minimizing environment and health hazards. [ABSTRACT FROM AUTHOR]

Abstract: The bacterial adhesion can be controlled (inhibit or promote) by different material surface characteristics like surface roughness, on which we concentrate in our study. Four different glass surfaces were prepared by polishing the glass plates with different gradations. The corresponding surface roughness was controlled by atomic force microscope and profilometer. For experiments we have used one Gram-positive bacterium (Staphylococcus aureus) and two Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli). The rate of adhered bacteria on glass surfaces was determined spectrophotometrically. The results showed that the rate of adhered bacteria increases with increasing surface roughness. The increased adhesion of bacteria on more rough surfaces is the interplay between the increasing effective surface and increasing number of defects on the surface. In order to keep all parameters under control we have also measured the surface charge density and hydrophobicity of bacteria and glass surfaces as well. [Copyright &y& Elsevier]