scholarly journals Sorption of SARS-CoV-2 Virus Particles to the Surface of Microplastics Released during Washing Processes

2021 ◽  
Vol 19 (1) ◽  
pp. 281
Author(s):  
Noemi Belišová ◽  
Barbora Konečná ◽  
Nikoleta Bachratá ◽  
Jozef Ryba ◽  
Alena Potočárová ◽  
...  
Keyword(s):  
Wash Water ◽  
Textile Fibers ◽  
Virus Particles ◽  
Washing Process

The research aims at washing processes as possible sources of microplastics, specifical microfibers in wastewater, and the behavior of the virus particles SARS-CoV-2 in wastewater after the washing process as well as their ability to sorb to the surface of microfibers, released from washing processes. The conclusions of the research point to the ability of the virus to attach to possible solid impurities such as textile fibers (microfibers) occurring in the sewer and to the ability of wash water to influence their possible occurrence in the sewer. The highest efficiency (more than 99%) of removal virus particles was after washing process, using liquid washing powder, and washing soda. These findings may gradually contribute to a better understanding of the behavior of the virus particles in the sewer.

Effect of Water Temperature on Bacterial Killing in Laundry

1987 ◽  
Vol 8 (5) ◽  
pp. 204-209 ◽  
Author(s):  
J.A. Smith ◽  
K.R. Neil ◽  
C.G. Davidson ◽  
R.W. Davidson
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Cold Water ◽  
Hot Water ◽  
Wash Water ◽  
Bacterial Killing ◽  
Bacterial Counts ◽  
Cost Of Energy ◽  
Washing Process ◽  
Killing Action

AbstractThe increasing cost of energy directed our attention to testing the feasibility of low temperature washing. Hospital laundries use formulated chemicals at high temperature wash waters of 66°C. Wash water effluents and fabric bacterial counts of heavily soiled linen were correlated with alkalinity and temperature measurements to investigate the bacterial killing action of hot and cold wash formulas. Terry towels were found to be contaminated with 107to 109organisms per 100 cm2at the beginning of the washing process. The most common gram-negative rods found wereKlebsiella, EnterobacterandSerratiaspecies. Staphylococci were the predominant gram-positives. Both cold and hot water washing including the bleach cycle reduced bacterial counts in fabric by 3 log10. Similarly, wash water cfu/mL declined 3 to 4 log10. A further 0.5 to 1.0 log10reduction was effected in the 93.3°C drying cycle. Low temperature wash formulas were comparable to high temperature laundry with respect to bacterial counts and species. Cold water formulas at 31.1°C offer an alternative method to reduce energy consumption and maintain bacteriological and esthetic linen quality.

Behavior of Shiga Toxigenic Escherichia coli Relevant to Lettuce Washing Processes and Consideration of Factors for Evaluating Washing Process Surrogates

2014 ◽  
Vol 77 (11) ◽  
pp. 1860-1867 ◽  
Author(s):  
KAIPING DENG ◽  
XUE WANG ◽  
LI-HAN YEN ◽  
HONGLIU DING ◽  
MARY LOU TORTORELLO
Keyword(s):  
Escherichia Coli ◽  
Bacterial Species ◽  
Wash Water ◽  
Lag Phase ◽  
Phenotypic Traits ◽  
Cross Contamination ◽  
Process Validation ◽  
E Coli ◽  
Hazard Characterization ◽  
Washing Process

Postharvest processes for fresh produce commonly include washing in water containing antimicrobial chemicals, such as chlorine; however, if the antimicrobials are not present in sufficient levels, washing can promote the spread of contamination that might be present. To understand cross-contamination risk during washing, we tested a collection of Shiga toxigenic Escherichia coli (STEC), including O157:H7 and other non-O157 strains, for certain traits during washing of fresh-cut lettuce, i.e., sensitivity to sublethal chlorine levels and ability to cross-contaminate (detach from and attach to) lettuce in the presence of sublethal chlorine levels. Nonpathogenic E. coli Nissle 1917 (EcN) and Pediococcus pentosaceus lactic acid bacterial species (LAB) were included as potential washing process validation surrogates. As measured by extension of the lag phase of growth in media containing 0.15 ppm of chlorine, chlorine sensitivity varied among the STECs. Cross-contamination was assessed by evaluating transfer of bacteria from inoculated to uninoculated leaves during washing. Without chlorine, similar transfer to wash water and uninoculated leaves was shown. In 1 ppm of chlorine, cross-contamination was not detected with most strains, except for the substantial transfer by a STEC O111 strain and EcN in some replicates. Strain O111 and EcN showed less inactivation in 0.25 ppm of chlorine water compared with O157 (P < 0.05). LAB showed similar transfer and similar chlorine inactivation to O157. Considering together the sublethal chlorine sensitivity and detachment/attachment traits, neither EcN nor LAB displayed optimal characteristics as washing process surrogates for the STEC strains, although further evaluation is needed. This work demonstrated a range of behaviors of STEC strains during lettuce washing and may be helpful in hazard characterization, identifying factors to consider for evaluating washing process efficacy, and identifying phenotypic traits to select surrogates to validate washing processes.

Physics of Fresh Produce Safety: Role of Diffusion and Tissue Reaction in Sanitization of Leafy Green Vegetables with Liquid and Gaseous Ozone-Based Sanitizers

2015 ◽  
Vol 78 (12) ◽  
pp. 2108-2116 ◽  
Author(s):  
MYKOLA V. SHYNKARYK ◽  
TARAS PYATKOVSKYY ◽  
HUSSEIN M. MOHAMED ◽  
AHMED E. YOUSEF ◽  
SUDHIR K. SASTRY
Keyword(s):  
High Speed ◽  
Fresh Produce ◽  
Tissue Reaction ◽  
Transport Processes ◽  
Wash Water ◽  
Produce Safety ◽  
Ozone Concentrations ◽  
Washing Process ◽  
Time Required ◽  
K 12

Produce safety has received much recent attention, with the emphasis being largely on discovery of how microbes invade produce. However, the sanitization operation deserves more attention than it has received. The ability of a sanitizer to reach the site of pathogens is a fundamental prerequisite for efficacy. This work addresses the transport processes of ozone (gaseous and liquid) sanitizer for decontamination of leafy greens. The liquid sanitizer was ineffective against Escherichia coli K-12 in situations where air bubbles may be trapped within cavities. A model was developed for diffusion of sanitizer into the interior of produce. The reaction rate of ozone with the surface of a lettuce leaf was determined experimentally and was used in a numerical simulation to evaluate ozone concentrations within the produce and to determine the time required to reach different locations. For aqueous ozone, the penetration depth was limited to several millimeters by ozone self-decomposition due to the significant time required for diffusion. In contrast, gaseous sanitizer was able to reach a depth of 100 mm in several minutes without depletion in the absence of reaction with surfaces. However, when the ozone gas reacted with the produce surface, gas concentration was significantly affected. Simulation data were validated experimentally by measuring ozone concentrations at the bottom of a cylinder made of lettuce leaf. The microbiological test confirmed the relationship between ozone transport, its self-decomposition, reaction with surrounding materials, and the degree of inactivation of E. coli K-12. Our study shows that decontamination of fresh produce, through direct contact with the sanitizer, is more feasible with gaseous than with aqueous sanitizers. Therefore, sanitization during a high-speed washing process is effective only for decontaminating the wash water.

scholarly journals Physicochemical Quality and Chemical Safety of Chlorine as a Reconditioning Agent and Wash Water Disinfectant for Fresh-Cut Lettuce Washing

2013 ◽  
Vol 79 (9) ◽  
pp. 2850-2861 ◽  
Author(s):  
Sam Van Haute ◽  
Imca Sampers ◽  
Kevin Holvoet ◽  
Mieke Uyttendaele
Keyword(s):  
Escherichia Coli ◽  
Water Contamination ◽  
Tap Water ◽  
Water Disinfection ◽  
Wash Water ◽  
Chemical Safety ◽  
Residual Concentration ◽  
Content Type ◽  
Washing Process ◽  
Fresh Cut

ABSTRACTChlorine was assessed as a reconditioning agent and wash water disinfectant in the fresh-cut produce industry. Artificial fresh-cut lettuce wash water, made from butterhead lettuce, was used for the experiments. In the reconditioning experiments, chlorine was added to artificial wash water inoculated withEscherichia coliO157 (6 log CFU/ml). Regression models were constructed based on the inactivation data and validated in actual wash water from leafy vegetable processing companies. The model that incorporated chlorine dose and chemical oxygen demand (COD) of the wash water accurately predicted inactivation.Listeria monocytogeneswas more resistant to chlorine reconditioning in artificial wash water thanSalmonellaspp. andEscherichia coliO157. During the washing process with inoculated lettuce (4 log CFU/g), in the absence of chlorine, there was a rapid microbial buildup in the water that accumulated to 5.4 ± 0.4 log CFU/100 ml after 1 h. When maintaining a residual concentration of 1 mg/liter free chlorine, wash water contamination was maintained below 2.7, 2.5, and 2.5 log CFU/100 ml for tap water and artificial process water with COD values of 500 and 1,000 mg O2/liter, respectively. A model was developed to predict water contamination during the dynamic washing process. Only minor amounts of total trihalomethanes were formed in the water during reconditioning. Total trihalomethanes accumulated to larger amounts in the water during the wash water disinfection experiments and reached 124.5 ± 13.4 μg/liter after 1 h of execution of the washing process in water with a COD of 1,000 mg O2/liter. However, no total trihalomethanes were found on the fresh-cut lettuce after rinsing.

scholarly journals Inactivation of Human Norovirus Genogroups I and II and Surrogates by Free Chlorine in Postharvest Leafy Green Wash Water

2017 ◽  
Vol 83 (22) ◽  
Author(s):  
Nathan Dunkin ◽  
ShihChi Weng ◽  
Joseph G. Jacangelo ◽  
Kellogg J. Schwab
Keyword(s):  
Time Course ◽  
The United States ◽  
Free Chlorine ◽  
Wash Water ◽  
Health Concern ◽  
Pathogenic Microorganisms ◽  
Cross Contamination ◽  
Murine Norovirus ◽  
Leafy Greens ◽  
Washing Process

ABSTRACT Human noroviruses (hNoVs) are a known public health concern associated with the consumption of leafy green vegetables. While a number of studies have investigated pathogen reduction on the surfaces of leafy greens during the postharvest washing process, there remains a paucity of data on the level of treatment needed to inactivate viruses in the wash water, which is critical for preventing cross-contamination. The objective of this study was to quantify the susceptibility of hNoV genotype I (GI), hNoV GII, murine norovirus (MNV), and bacteriophage MS2 to free chlorine in whole leaf, chopped romaine, and shredded iceberg lettuce industrial leafy green wash waters, each sampled three times over a 4-month period. A suite of kinetic inactivation models was fit to the viral reduction data to aid in quantification of concentration-time (CT) values. Results indicate that 3-log10 infectivity reduction was achieved at CT values of less than 0.2 mg · min/liter for MNV and 2.5 mg · min/liter for MS2 in all wash water types. CT values for 2-log10 molecular reduction of hNoV GI in whole leaf and chopped romaine wash waters were 1.5 and 0.9 mg · min/liter, respectively. For hNoV GII, CT values were 13.0 and 7.5 mg · min/liter, respectively. In shredded iceberg wash water, 3-log10 molecular reduction was not observed for any virus over the time course of experiments. These findings demonstrate that noroviruses may exhibit genogroup-dependent resistance to free chlorine and emphasize the importance of distinguishing between genogroups in hNoV persistence studies. IMPORTANCE Postharvest washing of millions of pounds of leafy greens is performed daily in industrial processing facilities with the intention of removing dirt, debris, and pathogenic microorganisms prior to packaging. Modest inactivation of pathogenic microorganisms (less than 2 log10) is known to occur on the surfaces of leafy greens during washing. Therefore, the primary purpose of the sanitizing agent is to maintain microbial quality of postharvest processing water in order to limit cross-contamination. This study modeled viral inactivation data and quantified the free-chlorine CT values that processing facilities must meet in order to achieve the desired level of hNoV GI and GII reduction. Disinfection experiments were conducted in industrial leafy green wash water collected from a full-scale fresh produce processing facility in the United States, and hNoV GI and GII results were compared with surrogate molecular and infectivity data.

Effects of natural antimicrobials on prevention and reduction of bacterial cross-contamination during the washing of ready-to-eat fresh-cut lettuce

2017 ◽  
Vol 23 (5) ◽  
pp. 403-414 ◽  
Author(s):  
Cristina Pablos ◽  
Alba Fernández ◽  
Alison Thackeray ◽  
Javier Marugán
Keyword(s):  
Antimicrobial Properties ◽  
Complete Removal ◽  
Wash Water ◽  
Plate Count ◽  
Salmonella Spp ◽  
Natural Antimicrobials ◽  
Benzyl Isothiocyanate ◽  
Standard Plate Count ◽  
Washing Process ◽  
Fresh Cut

Microbiological safety of the fresh-cut produce may not be guaranteed if the quality of wash water is not maintained. The use of natural antimicrobials as alternative to chlorine may offer interesting possibilities for disinfecting wash water. Antimicrobial properties of allyl- and benzyl-isothiocyanates, respectively, and chitosan against Salmonella spp. were evaluated by standard plate count. Minimal inhibitory concentration values were observed for benzyl-isothiocyanate and chitosan, corresponding to 50 and 1000 mgl−1, respectively. A 5 min washing of 25 g fresh-cut lettuce was performed. Transfer of Salmonella from the water to the produce was observed. Benzyl-isothiocyanate addition of 75 mgl−1 before starting the washing process gave rise to a complete removal of total bacteria and Salmonella in the wash water after 24 h before starting the second cycle. Antimicrobial benzyl-isothiocyanate effects have been demonstrated to persist after 48 h.

Mathematical Model and Equations of Wash Water Recycling in the Preparation of Layered Double Hydroxides

2012 ◽  
Vol 455-456 ◽  
pp. 1239-1243
Author(s):  
Yan Jun Lin ◽  
Qiang Wei ◽  
Xue Fei Jia ◽  
Dian Qing Li
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Layered Double Hydroxides ◽  
Water Saving ◽  
Wash Water ◽  
Water Recycling ◽  
Washing Process ◽  
Double Hydroxides

A wash water recycling method is used in the preparation of layered double hydroxides (LDHs). Based on the multiple-low-amount principle, a mathematical model and the equations of the washing process have been formulated. The experimental data are very similar to the calculated values, which means that the model and equations can be used to design and optimize the practical process of wash water recycling. The recycling of wash water in this way results in a water-saving of above 80%.

scholarly journals Antimicrobial Particle-Based Novel Sanitizer for Enhanced Decontamination of Fresh Produce

2019 ◽  
Vol 85 (8) ◽  
Author(s):  
Kang Huang ◽  
Nitin Nitin
Keyword(s):  
Fresh Produce ◽  
Unmet Need ◽  
Structural Features ◽  
Silica Particles ◽  
Organic Content ◽  
Wash Water ◽  
High Concentration ◽  
Content Type ◽  
Washing Process ◽  
Novel Concept

ABSTRACT Microbial food safety of raw or minimally processed fresh produce is a significant challenge. The current sanitation processes are effective for inactivation of bacteria in wash water but have limited efficacy (<2 log/g reduction) for inactivation of microbes on the surfaces of fresh produce. This study demonstrates a novel concept to enhance effectiveness of chlorine using a particle-based sanitizer to improve decontamination of fresh produce. In this concept, enhanced effectiveness is achieved by localized high concentration of chlorine bound to the surfaces of silica particles and improved surface contact of microparticles with the produce surface using mechanical shear during a washing process. The results of this study demonstrate that 500 ppm active chlorine can be bound to the surfaces of modified silica particles. These modified particles maintain over 90% of their initial chlorine content during extended storage in aqueous solution and provide improved inactivation of both Escherichia coli O157:H7, Listeria innocua, and Pseudomonas fluorescens in the presence of organic content in contrast to conventional chlorine sanitizer. The modified particles exhibit effective sanitation of fresh produce (>5-log reduction) in the presence of relatively high organic content (chemical oxygen demand of 500 mg/liter), demonstrating a potential to address a significant unmet need to improve fresh produce sanitation. The particle-based sanitizer had no significant effect on the quality of fresh lettuce. IMPORTANCE The limitation of current sanitation processes for inactivation of microbes on the surfaces of fresh produce is due to nonspecific consumption of sanitizers by reactions with the food matrix and complexity of surface chemistries and structural features of produce surfaces. This study demonstrates a novel approach to enhance sanitation effectiveness of fresh produce using a particle-based sanitizer. The particle-based sanitizer concept provides localized high concentration delivery of chlorine to the surfaces of fresh produce and enables more than 5 logs of inactivation of inoculated bacteria on fresh produce surfaces without significant changes in produce quality. The results of this study illustrate the potential of this approach to address the unmet need for improving sanitation of fresh produce. Further validation of this approach using a scaled-up produce washing system will enable commercialization of this novel concept.

Quality Control Analysis of the Potential for Asbestos Contamination During Tissue Processing inPathology Laboratories

2004 ◽  
Vol 128 (7) ◽  
pp. 781-784
Author(s):  
Ronald F. Dodson ◽  
Michael O'Sullivan ◽  
Samuel P. Hammar
Keyword(s):  
Water Sample ◽  
Lung Tissue ◽  
Wash Water ◽  
Control Analysis ◽  
Cross Contamination ◽  
Pathology Laboratory ◽  
Asbestos Fibers ◽  
Washing Process ◽  
Asbestos Related Disease ◽  
Asbestos Body

Abstract Context.—Various quality assurance procedures are applied in pathology and analytical microscopy laboratories to ensure accurate results. Objective.—To assess the potential of cross-contamination of tissue with asbestos fibers and asbestos bodies during the fixation and washing process. Design.—Lung tissue from 10 patients with potential asbestos-related disease was evaluated. Samples of fixative, water, and lung tissue from each case were evaluated by light and analytical transmission electron microscopy for asbestos bodies and uncoated asbestos fibers. Results.—The lung samples tested contained a range of asbestos bodies and uncoated asbestos fibers. One wash water sample contained one asbestos body. No asbestos bodies or uncoated asbestos fibers were found in any other water or fixative samples. Conclusions.—The absence of uncoated asbestos fibers in wash water or fixative samples argues that the fixation process stabilizes asbestos fibers within tissue and the protocol used in this pathology laboratory protects against cross-contamination of tissue. The finding of one asbestos body in one water sample further supports the efficiency of the protective controls used in the testing methods, since this asbestos body was in the external solution that was being discarded before tissue sampling occurred.

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