Cleaning in place: effect of local wall shear stress variation on bacterial removal from stainless steel equipment

Lelièvre, C.; Legentilhomme, P.; Gaucher, C.; Legrand, Jack; Faille, Christine; Bénézech, Thierry

doi:10.1016/s0009-2509(02)00019-2

Cited by 118 publications

(78 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Shear stresses similar to the one tested in this work can be found in different industrial equipment, pipes and accessories (Ahmed et al, 2011;Konuklar and Gunasekaran, 2002;Lelièvre et al, 2002;Liu et al, 2006).…”

Section: Cell Adhesion and Biofilm Assayssupporting

confidence: 75%

“…In industrial lines, bacterial adhesion and biofilm growth may be controlled by the shear forces applied on the surface by the fluid flow (Lelièvre et al, 2002). Shear forces can be controlled by either design of the equipment/pipe diameter or the flow rate used during operation, with hygienic design being preferred due to the cost and limitations of increasing the flow rate .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The impact of material properties, nutrient load and shear stress on biofouling in food industries

Moreira

Gomes

Simões

et al. 2015

Food and Bioproducts Processing

View full text Add to dashboard Cite

Abstract:In the food industry, biofilm formation in pipes, equipment and cooling systems increases maintenance costs, decreases operational efficiencies and is a source of contamination.Shear stress, nutrient load and surface material are important variables affecting the biofilm onset in industry. In this work, the combined impacts of these variables were assessed using three different materials (glass, copper and stainless steel), two nutrient loads (high and low nutrient medium) and two hydrodynamic conditions (static and dynamic). Initial adhesion and biofilm formation were studied in microplates usingEscherichia coli as a model organism.Surface material was the factor with the strongest impact and adhesion/biofilm formation were correlated with surface hydrophobicity. However, the impact of this variable was dependent on the nutrient load and imposed shear stress. It was also found that, for the majority of the situations tested, initial attachment performance is a good predictor of biofilm formation behaviour and that the effects observed during attachment are amplified during biofilm maturation. Since shear stress is a major determinant in cell adhesion, the results of this study may find application in industrial systems operating at flow rates between 0.001 and 600 m 3 h -1 depending on tube material and diameter.

show abstract

Section: Cell Adhesion and Biofilm Assayssupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

The impact of material properties, nutrient load and shear stress on biofouling in food industries

Moreira

Gomes

Simões

et al. 2015

Food and Bioproducts Processing

View full text Add to dashboard Cite

show abstract

“…A rotating cylinder reactor (Simões et al, 2005) was used to form biofilms on stainless steel cylinders at low shear stresses mimicking conditions found in engineered systems. The low shear stresses simulated with this reactor are often found in elbows, valves, dead zones, corners and in sudden pipe expansions (Jensen and Friis, 2005;Lelièvre et al, 2002). Also, typical shear stress values found in drinking water distribution systems are in the range of those used in this study (Gomes et al, 2014).…”

Section: Introductionmentioning

confidence: 69%

The effect of shear stress on the formation and removal of Bacillus cereus biofilms

Lemos

Mergulhão

Melo

et al. 2015

Food and Bioproducts Processing

View full text Add to dashboard Cite

A b s t r a c tThe influence of the shear stress (rw) under which biofilms were formed was assessed on their susceptibility to removal when exposed to chemical and mechanical stresses. A rotating cylinder reactor was used to form biofilms, allowing the simulation of rw conditions similar to those found in industrial settings, particularly in areas with low rw like elbows, corners, valves and dead zones. Bacillus cereus was used as a model bacterium for biofilm formation.Biofilms were formed on AISI316 stainless steel cylinders under different rw (estimated at 0.02, 0.12 and 0.17 Pa) for 7 days. Some phenotypic characteristics, including thickness, biomass production, cellular density and extracellular proteins and polysaccharides content were assessed. Biofilm density was found to increase significantly with rw while the thickness decreased. Also, biofilms formed at 0.02 Pa had lowest biomass content, cell density and extracellular polysaccharide content. Those characteristics were not statistically different for the biofilms formed under 0.12 and 0.17 Pa.Ex situ tests were performed by treating the biofilms with the biocide benzyldimethyldodecyl ammonium chloride (BDMDAC), followed by exposure to increasing rw conditions, up to 1.84 Pa (whereas the maximum rw used during growth was 0.17 Pa). The biofilms formed under low rw were more resistant to removal caused by the BDMDAC action alone. Those formed under higher rw were more resistant to the mechanical and the combined chemical and mechanical treatments. The amount of biofilm remaining on the cylinders, after both treatments was statistically similar for biofilms formed under 0.12 and 0.17Pa. The resistance of biofilms to removal by mechanical treatment (alone and combined with BDMDAC) was related to the amount of matrix polysaccharides.However, none of the methods investigated were able to remove all the biofilm from the cylinders. IntroductionThere is a lack of efficient strategies to clean stagnant zones in industrial plants (Brooks and Flint, 2008). Crevices, corners, dead zones, valves or areas where the mixing rate is low are almost inevitable. Stagnation promotes bacterial accumulation, ultimately leading to biofouling (Manuel et al., 2010). Biofouling is a damaging problem, affecting the energetic efficiency of industrial processes, causing corrosion of the surfaces, decreasing product quality and eventually promoting the spread of pathogens and resistant infectious diseases (Costerton et al., 1999;Ludensky, 2003;Srey et al., 2013). In industrial settings, surface disinfection is usually focused on the use of biocides, aiming to inactivate the microorganisms (Cloete et al., 1998;Faille et al., 2013). Since biofilms are complex biological structures adhered to a sur-face, these strategies often fail, as the removal of biomass is neglected. Hence, cleaning the biomass from the surfaces is fundamental for controlling biofilm development (Flemming, 2011).In the biofilm formation process, the hydrodynamic conditions define the transport of the cells, oxyg...

show abstract

“…Hydrodynamic effects are crucial for the cleaning efficiency, through the shear stress forces acting at the equipment walls (Lelièvre et al, 2002;Jensen et al, 2005;Blel et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Conditioning materials with biomacromolecules: Composition of the adlayer and influence on cleanability

Toure

Genet

Dupont‐Gillain

et al. 2014

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

AbbreviationsBSA: bovine serum albumin RFC: radial flow cell XPS: X-ray photoelectron spectroscopy 2 ABSTRACTThe influence of substrate hydrophobicity and biomacromolecules (dextran, bovine serum albumin -BSA) adsorption on the cleanability of surfaces soiled by spraying aqueous suspensions of quartz particles (10 to 30 µm size), then dried, was investigated using glass and polystyrene as substrates. The cleanability was evaluated using radial flow cell (RFC).The surface composition was determined by X-ray photoelectron spectroscopy (XPS). The interpretation of XPS data allowed the complexity due to the ubiquitous presence of organic contaminants to be coped with, and the surface composition to be expressed in terms of both the amount of adlayer and the mass concentration of adlayer constituents.When soiled with a suspension of particles in water, glass was much less cleanable than polystyrene, which was attributed to its much lower water contact angle, in agreement with previous observations on starch soil. Dextran was easily desorbed and did not affect the cleanability. The presence of BSA at the interface strongly improved the cleanability of glass while the contact angle did not change appreciably. In contrast, soiling polystyrene with quartz particles suspended in a BSA solution instead of water did not change markedly the cleanability, while the contact angle was much lower and the aggregates of soiling particles were more flat. These observations are explained by the major role of capillary forces developed upon drying, which influence the closeness of the contact between the soiling particles and the substrate and, thereby, the adherence of particles. The capillary forces are proportional to the liquid surface tension and depend in a more complex way on contact angles of the particles and of the substrate. The dependence of cleanability on capillary forces, and in particular on the liquid surface tension, is predominant as compared with its dependence on the size and shape of the soiling aggregates, which influence the efficiency of shear forces exerted by the flowing water upon cleaning.

show abstract

Cleaning in place: effect of local wall shear stress variation on bacterial removal from stainless steel equipment

Cited by 118 publications

References 24 publications

The impact of material properties, nutrient load and shear stress on biofouling in food industries

The impact of material properties, nutrient load and shear stress on biofouling in food industries

The effect of shear stress on the formation and removal of Bacillus cereus biofilms

Conditioning materials with biomacromolecules: Composition of the adlayer and influence on cleanability

Contact Info

Product

Resources

About