Knowledge Base

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Article

Visual inspection of surface sanitation: defining the conditions that enhance the human threshold for detection of food residues

Daeschel, D., Singh Rana, Y., Chen, L., Cai, S., Dando, R. and Snyder, A.B.

2023Food Control149109691

Keywordscleaning, decontamination

DisciplinesSocial sciences

CategoriesField work, Statistical analysis

Scale1e-6 m, 1e-6 to 1e-3 m / 1 to 60 s

Non-expert summaryVisual inspection is widely used in assessing and monitoring cleaning, sanitation and decontamination. This experimental study explored the degree of residual soiling on equipment surfaces that lies below the limit of visual detection. The goal of this study was to evaluate the limit of detection of visual inspections and establish evidence-based strategies to improve the implementation of this activity. 101 respondents completed a visual sensory test where each one looked at viewed 15 stainless steel and 15 white high density polyethylene sheets, clean or soiled with dry wheat flour, in a randomly generated order. They were asked if they could visually detect food residue on each surface and, if so, if the surface should be re-cleaned. They were also asked to answer this when they could touch the surfaces with a gloved hand. The impact of training, use of illumination, viewing angle and colour-contrast are quantified. The results provide a quantitative measure of the effectiveness of visual inspection, and factors than can influence this.

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Article

Lessons to learn from roadmapping in cleaning and decontamination

Wilson D. I., Christie G., Fryer P. J., Hall I. M., Landel J. R., Whitehead K. A.

2022Food and Bioproducts Processing135156-164

Keywordscleaning, decontamination

CategoryReview

Scaleless than 1e-9 m, 1e-9 to 1e-6 m, 1e-6 m, 1e-6 to 1e-3 m, 1e-3 m, 1e-3 to 1 m, 1 to 10 m, 10 to 1000 m, greater than 1 km / less than 1e-3 s, 1e-3 to 1 s, 1 to 60 s, 1 to 60 min, 1 to 24 hours, 1 to 30 days, 1 to 12 months, greater than 1 year

Non-expert summaryThis article presents an interdisciplinary roadmap showing the importance of cleaning and decontamination activities across a range of socio-economic sectors and in daily life. It captures the expertise and state-of-the art in terms of the fundamental understanding of the underpinning science behind cleaning and decontamination activities, as well as its practical implementation. The roadmap also highlights shortcomings and critical needs in the field at the scientific and practical levels, with some strategies to address them.

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Article

Shear flow over a protuberance on a plane wall

Pozrikidis, C.

1997Journal of Engineering Mathematics3129-42

Keywordsdecontamination, flow displacement, shear flow

DisciplinesApplied Mathematics, Fluid Mechanics

CategoryNumerical simulations

Non-expert summaryMany cleaning and decontamination operations employ a flow to detach or move a particle or foreign element (e.g. a piece of dust, baterium or a spore) from a surface. The presence of the element disturbs the flow near the wall. Knowledge of the flow field and the forces imposed on the element is useful for predicting or quantifying removal. This paper considers a simple shear flow of a Newtonian fluid over an axisymmetric protuberance (with uniform shape) on a plane wall. The full 3-D problem is formulated in terms of three scalar Fredholm integral equations of the first kind and is solved using a boundary-element method. The hydrodynamic force and torque exerted on the protuberance, and distribution of shear stresses, are calculated. There is good agreement with previous analytical computations for hemi-spherical and spherical shapes.

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Article

Mechanisms of photoresist dissolution

Hunek, B., Cussler, E.L.

2002AIChEJ48(4)661-672

Keywordscleaning, decontamination, mass transfer

DisciplinesChemical Engineering, Chemistry

CategoryLaboratory experiments

Scale1e-6 to 1e-3 m / 1e-3 to 1 s, 1 to 60 s, 1 to 60 min

Non-expert summaryPhotoresists are an example of long chain molecules which dissolve in the presence of alkali. Dissolution involves the transport of hydoxyl ions (OH-) into the layer: they react with the photoresist and, depending on the temperature (above or below the upper critical solution temperature, UCST), it will either be transported by diffusion through the fluid boundary layer (above UCST) or form a gel phase (below the UCST), introducing an additional diffusion step in the reaction and mass transfer processes. A physico-chemical model of the process is presented here, applied to novolak resins, which can be applied to other polymeric systems including printing inks and dairy protein foulants. Experiments are performed with a spinning disk apparatus, which gives well defined mass transfer conditions.

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Miscellaneous

Waste Estimation Support Tool (WEST)

US Environment Protection Agency

2021

Keywordscleaning, decontamination

DisciplinesMicrobiology, Statistics & Probabilities

Scale1 to 10 m, 10 to 1000 m, greater than 1 km / 1 to 60 min, 1 to 24 hours, 1 to 30 days, 1 to 12 months, greater than 1 year

Non-expert summaryThe US Environment Protection Agency (EPA) has generated a number of management tools related to cleaning and decontamination. The EPA website states that "Management of waste from a radiological dispersal device (RDD) incident would likely constitute a large part of the remediation cost and effort. The U.S. EPA’s RDD Waste Estimation Support Tool (WEST) is a planning tool for estimating the potential volume and radioactivity levels of waste generated by a radiological incident and subsequent decontamination efforts. WEST supports decision makers by generating a first-order estimate of the quantity and characteristics of waste resulting from a radiological incident, and allows the user to evaluate various decontamination/demolition strategies to examine the impact of those strategies on waste generation. "

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Technical report

Bio-Response Operational Testing and Evaluation (BOTE) Project – Phase 1: Decontamination Assessment

US Environment Protection Agency

2013

Institution / OrganisationUS Environment Protection Agency

Keywordsbacteria, cleaning, decontamination

DisciplinesMicrobiology

CategoryField work

Scale1 to 10 m, 10 to 1000 m, greater than 1 km / 1 to 60 min, 1 to 24 hours, 1 to 30 days, 1 to 12 months, greater than 1 year

Non-expert summaryThe US Environment Protection Agency led a multi-agency investigation into the response to a release of a biological agent. The report summary states "The Bio-response Operational Testing and Evaluation (BOTE) Project was a multi-agency effort designed to operationally test and evaluate a response to a biological incident (release of Bacillus anthracis spores, the causative agent for anthrax) from initial public health and law enforcement response through environmental remediation. The BOTE Project consisted of two distinct phases, both using the same non-pathogenic simulant (or surrogate) for these spores. Phase 1 was a field-level decontamination assessment, and Phase 2 was an operational exercise involving key federal agencies responsible for the forensic investigation, public health assessment, and remediation following a biological incident. Phase 1 was designed to address site remediation after the release of a simulant within a facility in an operational setting, drawing upon the recent advances in both biological sampling and decontamination. "

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Technical report

Tabletop exercise report – Sample plan development for biological incidents, large and small – Trade-Off Tool for Sampling (TOTS)

Calfee, W., Boe, T., Mickelsen, L., Johnson, C., James, R.

2020

Institution / OrganisationUS Environment Protection Agency

Keywordsbacteria, cleaning, decontamination

DisciplinesMicrobiology

CategoryReview

Scale1e-3 to 1 m, 1 to 10 m, 10 to 1000 m, greater than 1 km / 1 to 60 min, 1 to 24 hours, 1 to 30 days, 1 to 12 months, greater than 1 year

Non-expert summaryThe Report Executive Summary states: "The Trade-off Tool for Sampling (TOTS) is a tool under development that aids planners, responders, and subject matter experts in developing defensible yet practicable sample collection plans following a biological contamination incident. The U.S. Environmental Protection Agency (EPA) held a table-top exercise (TTX) with two separate groups of people. The purpose of the TTX was to gather critical end-user feedback on the utility of the tool for future revisions of TOTS and to increase collective (responders, planners, and researchers) understanding of challenges during the sampling and analysis plan (SAP) development for biological incidents, all for the goal of strengthening EPA’s capabilities in this area. The first TTX session was held at the 2019 EPA International Decontamination Conference in Norfolk, Virginia (November 18, 2019), and the second TTX session was held at the EPA On-scene Coordinator (OSC) Academy in Chicago, Illinois (February 26, 2020). The ultimate goal is to provide EPA planners and operational personnel (e.g., on-scene coordinators) the tools and resources necessary to effectively and efficiently plan and execute EPA’s response obligations."

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Technical report

A Review of biological agent sampling methods and application to a wide-area incident scenario to characterize time and resource demands

Calfee, W., Lee, S., Boe, T.

2017

Institution / OrganisationUS Environment Protection Agency

Keywordsbacteria, cleaning, decontamination, risk

DisciplinesMicrobiology

CategoriesField work, Review

Scale1e-3 to 1 m, 1 to 10 m, 10 to 1000 m, greater than 1 km / 1 to 60 s, 1 to 60 min, 1 to 24 hours, 1 to 30 days, 1 to 12 months, greater than 1 year

Non-expert summaryThe executive summary of this US EPA report states: "A large-scale aerosol release of a persistent, disease-causing biological agent can result in contamination of a wide area, and may require significant time and resources for recovery depending on the severity of adverse health effects on the exposed population(s). Many unknowns are associated with characterization and clearance sampling during response to a wide-area (including indoor, outdoor, and underground area) biological incident. The biological agent and its characteristics, the release mechanism, amount of contaminant released, and a plethora of environmental and meteorological factors are completely separate, yet interconnected processes that greatly influence the extent and level of contamination. Similarly, decisions related to the sampling strategy (i.e., sample medium, sampling area, spacing, etc.) will affect the cost, time, amount of waste generated, and personnel (i.e., resource demand) required to characterize and clear the contaminated area. The process of understanding how these elements influence one another and contribute to the overall problem is referred to as a systems approach. To what degree sampling and, more specifically, variations in the sampling strategy interact and contribute to overall resource demand, following a wide area biological incident, is still largely unknown. To date, there have been no attempts to model characterization sampling following a wide-area biological incident."

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Review article

Instabilities in blistering

Juel, A., Pihler-Puzović, D., Heil, M.

2018Annual Review of Fluid Mechanics50691-714

Keywordscavity flow, decontamination, elasticity theory, fingering instabilities, flow displacement, flow-structure interaction, Hele-Shaw flows, interfacial dynamics, lubrication theory, pattern formation

DisciplinesFluid Mechanics, Physics

CategoryReview

Scale1e-9 to 1e-6 m, 1e-6 m, 1e-6 to 1e-3 m / 1e-3 to 1 s, 1 to 60 s

Non-expert summaryThis is a review of the fluid mechanics associated with blistering, which occurs when a thin solid layer locally separates from an underlying substrate through cracking of a bulk material, delamination of a composite material, or peeling of a thin layer (membrane) adhered to the substrate by a thin layer of viscous fluid. The focus of the review is on the latter case, where the expansion of the newly formed blister by fluid injection occurs via a displacement flow, which peels the adhered surfaces apart through a two-way interaction between flow and deformation. These blisters are prone to fluid- and solid-mechanical instabilities. If the injected fluid is less viscous than the fluid already occupying the gap, patterns of short and stubby fingers (fingering) form on the propagating fluid interface. Buckling/wrinkling instabilities of the delaminated layer can arise for sufficiently thin membranes and can interact with the fluid mechanical fingering instability.

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Article

Three-dimensional advective–diffusive boundary layers in open channels with parallel and inclined walls

Etzold, M.A., Landel, J.R., Dalziel, S.B.

2020International Journal of Heat and Mass Transfer153119504

Keywordscleaning, decontamination, drop, heat transfer, mass transfer, narrow channel

DisciplinesChemical Engineering, Fluid Mechanics

CategoriesNumerical simulations, Theoretical modelling

Scale1e-6 to 1e-3 m, 1e-3 m, 1e-3 to 1 m / 1e-3 to 1 s, 1 to 60 s, 1 to 60 min, 1 to 24 hours

Non-expert summaryThe authors consider the steady laminar advective transport of a diffusive component released at the base of a narrow three-dimensional longitudinal open channel with non-absorbing side walls and rectangular or truncated-wedge-shaped cross-sections: the findings are relevant to heat and mass transfer applications in confined U-shaped or V-shaped channels (or trenches) such as might arise in the decontamination and cleaning of narrow gaps, crevices and boundary features on walls or other surfaces, and well as transport processes in chemical or biological microfluidic devices. The fluid flows along the channel in the laminar regime and there is no flux or slip on the side walls. Numerical simulations are conducted for various duct shapes and the rate of mass transfer from the base is calculated: this is used to evaluate the dimensionless mass transfer coefficient, the Sherwood number. The results for 3-D (constant cross section, long in the direction of flow) are compared favourably with results for a simplified, 2-D, calculation.

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Article

Modelling mass casualty decontamination systems informed by field exercise data

Egan, J.R., Amlôt, R.

2012International Journal of Environmental Research and Public Health93685-3710

Keywordschemical warfare agent simulant, decontamination, emergency response, people

DisciplinesStatistics & Probabilities

CategoriesField work, Numerical simulations

Scale1 to 10 m, 10 to 1000 m, greater than 1 km / 1 to 24 hours, 1 to 30 days

Non-expert summaryThe management of decontamination of the population (who were mobile enough to walk through a showering lane) in the event of a large-scale chemical release in the UK was modelled, based on data collected in field trials. The movement of volunteer casualties at two mass decontamination field exercises was monitored using passive Radio Frequency Identification tags and detection mats. The data were used to inform a computer model of the UK fire and rescue service component of the mass decontamination process. This identified bottlenecks in the process and led to recommendations for change, particularly in the re-dressing part of the process.

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Article

Sliding, pinch-off and detachment of a droplet on a wall in shear flow

Ding, H., Gilani, M.N.H., Spelt, P.D.M.

2010Journal of Fluid Mechanics644217–244

Keywordsdecontamination, drop, hydrodynamics, interfacial dynamics, shear flow

DisciplinesChemical Engineering, Fluid Mechanics

CategoriesNumerical simulations, Theoretical modelling

Non-expert summaryThis modelling study considers what happens after a droplet is set into motion by the action of an impose shear flow. Inertial effects and contact-angle hysteresis are both considered. A number of flow regimes are investigated, including steadily moving drops, partial and entire droplet entrainment. The critical conditions (capillary number) for the onset of entrainment are determined for pinned as well as for moving drops. The approach to breakup is then investigated in detail, including the growth of a ligament on a drop, and the reduction of the radius of a pinching neck. A model based on an energy argument is proposed for the rate of elongation of ligaments. The paper concludes with an investigation of detachment of a hydrophobic droplet from a solid wall.

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