Listeria Monocytogenes Biofilm Removal Using Different Commercial Cleaning Agents

Effective cleaning and disinfection (C&D) is pivotal for the control of Listeria monocytogenes in food processing environments. Bacteria in biofilms are protected from biocidal action, and effective strategies for the prevention and removal of biofilms are needed. In this study, different C&D biofilm control strategies on pre-formed L. monocytogenes biofilms on a conveyor belt material were evaluated and compared to the effect of a conventional chlorinated, alkaline cleaner (agent A). Bacterial reductions up to 1.8 log were obtained in biofilms exposed to daily C&D cycles with normal user concentrations of alkaline, acidic, or enzymatic cleaning agents, followed by disinfection using peracetic acid. No significant differences in bactericidal effects between the treatments were observed. Seven-day-old biofilms were more tolerant to C&D than four-day-old biofilms. Attempts to optimize biofilm eradication protocols for four alkaline, two acidic, and one enzymatic cleaning agent, in accordance with the manufacturers’ recommendations, were evaluated. Increased concentrations, the number of subsequent treatments, the exposure times, and the temperatures of the C&D agents provided between 4.0 and >5.5 log reductions in colony forming units (CFU) for seven-day-old L. monocytogenes biofilms. Enhanced protocols of conventional and enzymatic C&D protocols have the potential for improved biofilm control, although further optimizations and evaluations are needed.

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Microbial Ecology Evaluation of an Iberian Pig Processing Plant through Implementing SCH Sensors and the Influence of the Resident Microbiota on Listeria monocytogenes

Applied Sciences ◽

10.3390/app9214611 ◽

2019 ◽

Vol 9 (21) ◽

pp. 4611 ◽

Cited By ~ 4

Author(s):

Anne-Sophie Hascoët ◽

Carolina Ripolles-Avila ◽

Alfons Eduard Guerrero-Navarro ◽

José Juan Rodríguez-Jerez

Keyword(s):

Listeria Monocytogenes ◽

Foodborne Pathogens ◽

Food Industry ◽

Control Strategies ◽

Plate Count ◽

Processing Plant ◽

Biochemical Tests ◽

Bacillus Spp ◽

Iberian Pig ◽

Cleaning And Disinfection

There is a whole community of microorganisms capable of surviving the cleaning and disinfection processes in the food industry. These persistent microorganisms can enhance or inhibit biofilm formation and the proliferation of foodborne pathogens. Cleaning and disinfection protocols will never reduce the contamination load to 0; however, it is crucial to know which resident species are present and the risk they represent to pathogens, such as Listeria monocytogenes, as they can be further used as a complementary control strategy. The aim of this study was to evaluate the resident surface microbiota in an Iberian pig processing plant after carrying out the cleaning and disinfection processes. To do so, surface sensors were implemented, sampled, and evaluated by culture plate count. Further, isolated microorganisms were identified through biochemical tests. The results show that the surfaces are dominated by Bacillus spp., Pseudomonas spp., different enterobacteria, Mannheimia haemolytica, Rhizobium radiobacter, Staphylococcus spp., Aeromonas spp., lactic acid bacteria, and yeasts and molds. Moreover, their probable relationship with the presence of L. monocytogenes in three areas of the plant is also explained. Further studies of the resident microbiota and their interaction with pathogens such as L. monocytogenes are required. New control strategies that promote the most advantageous profile of microorganisms in the resident microbiota could be a possible alternative for pathogen control in the food industry. To this end, the understanding of the resident microbiota on the surfaces of the food industry and its relation with pathogen presence is crucial.

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Behavior-based control of insect crop pests

10.1093/oso/9780198797500.003.0020 ◽

2018 ◽

Author(s):

Sandra A. Allan

Keyword(s):

Insect Pests ◽

Control Strategies ◽

Insect Behavior ◽

Life Cycles ◽

Economic Damage ◽

Mass Trapping ◽

Ecological Traits ◽

Crop Pests ◽

Effective Strategies ◽

Crop Development

Manipulation of insect behavior can provide the foundation for effective strategies for control of insect crop pests. A detailed understanding of life cycles and the behavioral repertoires of insect pests is essential for development of this approach. A variety of strategies have been developed based on behavioral manipulation and include mass trapping, attract-and-kill, auto-dissemination, mating and host plant location disruption, and push-pull. Insight into application of these strategies for insect pests within Diptera, Lepidoptera, Coleoptera, and Hemiptera/Thysanoptera are provided, but first with an overview of economic damage and traditional control approaches, and overview of relevant behavioral/ecological traits. Then examples are provided of how these different control strategies are applied for each taxonomic group. The future of these approaches in the context of altered crop development for repellency or as anti-feedants, the effects of climate change and the risks of behaviorally-based methods are discussed.

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Evaluation of a Continuous Decontamination Technology in an Intensive Care Unit

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.1201 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s519-s519

Author(s):

Tami Inman BSN ◽

David Chansolme

Keyword(s):

Intensive Care Unit ◽

Intensive Care ◽

Urban Hospital ◽

Patient Room ◽

Colony Forming Units ◽

Prevention Interventions ◽

Continuous Application ◽

Low Levels ◽

Healthcare Associated ◽

Cleaning And Disinfection

Background: The scientific literature increasingly indicates the need for the development of continuous disinfection to address the persistent contamination and recontamination that occurs in the patient rooms despite routine cleaning and disinfection. Methods: To determine a baseline microbial burden level on patient room surfaces in the intensive care unit (ICU) of a large urban hospital, 50 locations were swabbed for total colony-forming units (CFU) and the prevalence of methicillin-resistant Staphylococcus aureus (MRSA). Once the baseline in ICU patient rooms was established, 5 novel decontamination devices were installed in the HVAC ducts near these patient rooms. The devices provide a continuous low-level application of oxidizing molecules, predominately hydrogen peroxide. These molecules exit the duct and circulate in the patient room through normal convection, landing on all surfaces. After activation, environmental sampling was conducted every 4 weeks for 4 months. The effect from continuous low levels of oxidizing molecules on the intrinsic microbial burden and the prevalence of MRSA were analyzed. In addition to external laboratory reports, the facility tracked healthcare-associated infections (HAIs) in the unit. HAI data were averaged by month and were compared to the preactivation average in the same unit. Results: The preactivation average microbial burden found on the 50 locations were 179,000 CFU per 100 in2. The prevalence of MRSA was 71% with an average of 81 CFU per 100 in2. After activation of the devices, levels of microbial burden, prevalence of MRSA, and average monthly HAI rates were all significantly lower on average: 95% reduction in average microbial burden (8,206 CFU per 100 in2); 81% reduction in the prevalence of MRSA (13% vs 71%); 54% reduction in the average of healthcare-onset HAIs. All data were obtained from the averages of sampling data for 4 weeks during the 4-month trial period. Conclusions: The continuous application of low levels of oxidizing molecules throughout the patient rooms of an ICU demonstrated 3 outcomes: reduced overall surface microbial burden, lowered the incidence of MRSA, and significantly decreased the monthly average HAI rate. Please note, the ICU ran other infection prevention interventions at this time, including standard cleaning, as well as and their standard disinfecting techniques.Funding: This study was supported by the CASPR Group.Disclosures: None

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Efficacy of Three Commercial Disinfectants in Reducing Microbial Surfaces’ Contaminations of Pharmaceuticals Hospital Facilities

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18020779 ◽

2021 ◽

Vol 18 (2) ◽

pp. 779

Author(s):

Giuseppina Di Martino ◽

Salvatore Pasqua ◽

Bruno Douradinha ◽

Francesco Monaco ◽

Chiara Di Bartolo ◽

...

Keyword(s):

United States Pharmacopeia ◽

Log10 Reduction ◽

Colony Forming Units ◽

Before And After ◽

Disinfection Procedure ◽

Cleaning And Disinfection ◽

States Pharmacopeia ◽

Representative Samples ◽

Correct Implementation ◽

Reduction Index

To evaluate and validate the efficacy of disinfectants used in our cleaning procedure, in order to reduce pharmaceutical hospital surfaces’ contaminations, we tested the action of three commercial disinfectants on small representative samples of the surfaces present in our hospital cleanrooms. These samples (or coupons) were contaminated with selected microorganisms for the validation of the disinfectants. The coupons were sampled before and after disinfection and the microbial load was assessed to calculate the Log10 reduction index. Subsequently, we developed and validated a disinfection procedure on real surfaces inside the cleanrooms intentionally contaminated with microorganisms, using approximately 107–108 total colony forming units per coupon. Our results showed a bactericidal, fungicidal, and sporicidal efficacy coherent to the acceptance criteria suggested by United States Pharmacopeia 35 <1072>. The correct implementation of our cleaning and disinfection procedure, respecting stipulated concentrations and contact times, led to a reduction of at least 6 Log10 for all microorganisms used. The proposed disinfection procedure reduced the pharmaceutical hospital surfaces’ contaminations, limited the propagation of microorganisms in points adjacent to the disinfected area, and ensured high disinfection and safety levels for operators, patients, and treated surfaces.

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PSIX-18 Laurate and its glycerol monoester, monolaurin, as potential additives to control Listeria monocytogenes and tetracycline resistant Enterococcus faecalis in air-exposed silage

Journal of Animal Science ◽

10.1093/jas/skaa278.724 ◽

2020 ◽

Vol 98 (Supplement_4) ◽

pp. 414-415

Author(s):

Yamicela Castillo-Castillo ◽

Marina Ontiveros ◽

Eric J Scholljegerdes ◽

Robin Anderson ◽

Claudio Arzola-Alvarez ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Enterococcus Faecalis ◽

Brain Heart Infusion ◽

Bactericidal Effect ◽

Complete Elimination ◽

Gram Positive Bacteria ◽

Viable Cells ◽

Colony Forming Units ◽

Feed Value ◽

Risk Infection

Abstract Silages can harbor pathogenic and antimicrobial resistant microbes which risk infection of food-producing animals. Livestock producers need effective yet environmentally friendly interventions to preserve the feed value of these fermented materials. Medium chain fatty acids such as laurate and its glycerol monoester, monolaurin, are potent inhibitors of many Gram-positive bacteria and when tested at 5 mg/mL in anaerobic cultures (n = 3/treatment) inoculated with 105 colony forming units (CFU) of Listeria monocytogenes and grown at 37oC in ½ strength Brain Heart infusion broth achieved near complete elimination of viable cells after 6 h compared to a 2.2 ± 0.1 log10 CFU/mL increase observed in controls. Culture of a tetracycline-resistant Enterococcus faecalis with 5 mg laurate/mL likewise achieved near complete elimination of viable cells (5 log10 CFU/mL) by 6 h incubation. The bactericidal effect of 5 mg monolaurin was less against E. faecalis, achieving a decrease of 1.8 ± 0.2 log10 CFU/mL and not decreased further after 24 h. When tested against air-exposed silage, pH 7.53 (4 g), mixed with 4 mL water, 5 mg laurate or monolaurin decreased viability of experimentally-inoculated L. monocytogenes (105 CFU/g silage) more (P < 0.05) than untreated controls after 24 h aerobic incubation (22oC), with viable counts being decreased 6.3 ± 0.1, 5.9 ± 0.8 and 4.5 ± 0.1 log10 CFU/g, respectively. In contrast, viable recovery of the experimentally-inoculated (105 CFU/g) tetracycline-resistant E. faecalis was reduced more (P < 0.05) than controls (decreased 0.7 ± 0.1 log10 CFU/g) after 6 h incubation when similarly tested with laurate and monolaurin (1.7 ± 0.5 and 3.0 ± 0.9 log10 CFU/g, respectively) but counts after 24 h were similar, decreasing on average 2.0 ± 0.5 log10 CFU/g). Results indicate laurate and monolaurin may be useful in killing L. monocytogenes and tetracycline-resistant E. faecalis during silage feed-out.

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Anti-adhesion of probiotic Enterococcus faecium WEFA23 against five pathogens and the beneficial effect of its S-layer proteins against Listeria monocytogenes

Canadian Journal of Microbiology ◽

10.1139/cjm-2018-0031 ◽

2019 ◽

Vol 65 (3) ◽

pp. 175-184

Author(s):

Yao He ◽

Xiongpeng Xu ◽

Fen Zhang ◽

Di Xu ◽

Zhengqi Liu ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Enterococcus Faecium ◽

Probiotic Strain ◽

Antagonistic Activity ◽

Bacterial Surface ◽

Colony Forming Units ◽

Infant Feces ◽

Adhesion Activity ◽

Displacement Assays ◽

Different Levels

Enterococcus faecium WEFA23 is a potential probiotic strain isolated from Chinese infant feces. In this study, the antagonistic activity of E. faecium WEFA23 on adhesion to pathogens was investigated. Enterococcus faecium WEFA23 was able to compete, exclude, and displace the adhesion of Escherichia coli O157:H7, Salmonella Typhimurium ATCC 13311, Listeria monocytogenes CMCC54007, Staphylococcus aureus CMCC26003, and Shigella sonnei ATCC 25931 to Caco-2 cells. Among them, L. monocytogenes achieved the strongest inhibition rate in both competition and displacement assays. Those anti-adhesion capacities were related to the bacterial physicochemical properties (hydrophobicity, auto-aggregation, and co-aggregation) of the bacterial surface. For L. monocytogenes, the anti-adhesion capacity was affected by the heat treatment, cell density, and growth phase of E. faecium WEFA23; 108 colony-forming units of viable cells per millilitre at the stationary phase exhibited the strongest anti-adhesion activity. In addition, removal of S-layer proteins of E. faecium WEFA23 by treatment with 5 mol/L LiCl significantly decreased its adhesion capacity, and those S-layer proteins were able to compete, displace, and exclude L. monocytogenes at different levels. Both cells and S-layer proteins of E. faecium WEFA23 significantly reduced the apoptosis of Caco-2 cells induced by L. monocytogenes, which was mediated by caspase-3 activation. This study might be helpful in understanding the anti-adhesion mechanism of probiotics against pathogens.

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Quantitative Risk Assessment of Listeriosis-Associated Deaths Due to Listeria monocytogenes Contamination of Deli Meats Originating from Manufacture and Retail

Journal of Food Protection ◽

10.4315/0362-028x-73.4.620 ◽

2010 ◽

Vol 73 (4) ◽

pp. 620-630 ◽

Cited By ~ 51

Author(s):

ABANI K. PRADHAN ◽

RENATA IVANEK ◽

YRJÖ T. GRÖHN ◽

ROBERT BUKOWSKI ◽

IFIGENIA GEORNARAS ◽

...

Keyword(s):

Risk Assessment ◽

Listeria Monocytogenes ◽

Relative Risk ◽

Storage Temperature ◽

Control Strategies ◽

Quantitative Risk Assessment ◽

Sensitivity Analyses ◽

Effective Control ◽

Lag Phase ◽

Reported Data

The objective of this study was to estimate the relative risk of listeriosis-associated deaths attributable to Listeria monocytogenes contamination in ham and turkey formulated without and with growth inhibitors (GIs). Two contamination scenarios were investigated: (i) prepackaged deli meats with contamination originating solely from manufacture at a frequency of 0.4% (based on reported data) and (ii) retail-sliced deli meats with contamination originating solely from retail at a frequency of 2.3% (based on reported data). Using a manufacture-to-consumption risk assessment with product-specific growth kinetic parameters (i.e., lag phase and exponential growth rate), reformulation with GIs was estimated to reduce human listeriosis deaths linked to ham and turkey by 2.8- and 9-fold, respectively, when contamination originated at manufacture and by 1.9- and 2.8-fold, respectively, for products contaminated at retail. Contamination originating at retail was estimated to account for 76 and 63% of listeriosis deaths caused by ham and turkey, respectively, when all products were formulated without GIs and for 83 and 84% of listeriosis deaths caused by ham and turkey, respectively, when all products were formulated with GIs. Sensitivity analyses indicated that storage temperature was the most important factor affecting the estimation of per annum relative risk. Scenario analyses suggested that reducing storage temperature in home refrigerators to consistently below 7°C would greatly reduce the risk of human listeriosis deaths, whereas reducing storage time appeared to be less effective. Overall, our data indicate a critical need for further development and implementation of effective control strategies to reduce L. monocytogenes contamination at the retail level.

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Recurrent and Sporadic Listeria monocytogenes Contamination in Alheiras Represents Considerable Diversity, Including Virulence-Attenuated Isolates

Applied and Environmental Microbiology ◽

10.1128/aem.02912-06 ◽

2007 ◽

Vol 73 (12) ◽

pp. 3887-3895 ◽

Cited By ~ 37

Author(s):

M. T. S. Felï¿½cio ◽

T. Hogg ◽

P. Gibbs ◽

P. Teixeira ◽

M. Wiedmann

Keyword(s):

Listeria Monocytogenes ◽

Control Strategies ◽

Tetracycline Resistance ◽

The United States ◽

Pulsed Field Gel Electrophoresis ◽

Pathogenic Potential ◽

Molecular Serotyping ◽

Production And Distribution ◽

Invasion Assays

ABSTRACT Microbiological characterization of alheiras, traditional smoked meat sausages produced in northern Portugal, had previously shown that more than 60% of the lots analyzed were contaminated with Listeria monocytogenes at levels higher than 100 CFU/g. In order to better understand L. monocytogenes contamination patterns in alheiras, we characterized 128 L. monocytogenes isolates from alheiras using a variety of subtyping techniques (i.e., molecular serotyping; arsenic, cadmium, and tetracycline resistance typing; and pulsed-field gel electrophoresis [PFGE]). Subtyping of isolates from products collected on two separate dates provided evidence for the persistence of specific L. monocytogenes PFGE types in the production and distribution chains of alheiras from four different processors. A subset of 21 isolates was further characterized using ribotyping and Caco-2 cell invasion assays to evaluate the pathogenic potential of L. monocytogenes present in alheiras. Caco-2 invasion assays revealed seven isolates with invasion efficiencies that were less than 20% of that of the control strain 10403S. All seven isolates had premature stop codons in inlA that represented three distinct mutations, which had previously been observed in isolates from the United States or France. Our findings indicate the need for a comprehensive approach to control L. monocytogenes in alheiras, including strategies to reduce persistence. The presence of considerable diversity in invasion phenotypes among L. monocytogenes strains present in alheiras, including the presence of subtypes likely to be virulence attenuated, may provide an opportunity to initially focus control strategies on the subtypes most likely to cause human disease.

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Ultrasonic Cleaning of Conveyor Belt Materials Using Listeria monocytogenes as a Model Organism

Journal of Food Protection ◽

10.4315/0362-028x-70.3.758 ◽

2007 ◽

Vol 70 (3) ◽

pp. 758-761 ◽

Cited By ~ 15

Author(s):

RIINA TOLVANEN ◽

JANNE LUNDÉN ◽

HANNU KORKEALA ◽

GUN WIRTANEN

Keyword(s):

Stainless Steel ◽

Listeria Monocytogenes ◽

Model Organism ◽

Conveyor Belt ◽

Difficult Problem ◽

Cleaning Efficiency ◽

Ultrasonic Cleaning ◽

Plastic Materials ◽

Significant Difference ◽

Logarithmic Reduction

Persistent Listeria monocytogenes contamination of food industry equipment is a difficult problem to solve. Ultrasonic cleaning offers new possibilities for cleaning conveyors and other equipment that are not easy to clean. Ultrasonic cleaning was tested on three conveyor belt materials: polypropylene, acetal, and stainless steel (cold-rolled, AISI 304). Cleaning efficiency was tested at two temperatures (30 and 45°C) and two cleaning times (30 and 60 s) with two cleaning detergents (KOH, and NaOH combined with KOH). Conveyor belt materials were soiled with milk-based soil and L. monocytogenes strains V1, V3, and B9, and then incubated for 72 h to attach bacteria to surfaces. Ultrasonic cleaning treatments reduced L. monocytogenes counts on stainless steel 4.61 to 5.90 log units; on acetal, 3.37 to 5.55 log units; and on polypropylene, 2.31 to 4.40 log units. The logarithmic reduction differences were statistically analyzed by analysis of variance using Statistical Package for the Social Sciences software. The logarithmic reduction was significantly greater in stainless steel than in plastic materials (P < 0.001 for polypropylene, P = 0.023 for acetal). Higher temperatures enhanced the cleaning efficiency in tested materials. No significant difference occurred between cleaning times. The logarithmic reduction was significantly higher (P = 0.013) in cleaning treatments with potassium hydroxide detergent. In this study, ultrasonic cleaning was efficient for cleaning conveyor belt materials.

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Maximizing trickling filter nitrification rates through biofilm control: research review and full scale application

Water Science & Technology ◽

10.2166/wst.1997.0060 ◽

1997 ◽

Vol 36 (1) ◽

pp. 255-262 ◽

Cited By ~ 7

Author(s):

Denny S. Parker ◽

Tom Jacobs ◽

Erich Bower ◽

Dennis W. Stowe ◽

Greg Farmer

Keyword(s):

Control Strategies ◽

Treatment Plant ◽

Ammonia Nitrogen ◽

Full Scale ◽

Research Review ◽

Trickling Filter ◽

Trickling Filters ◽

The Past ◽

Biofilm Control ◽

Control Research

Tertiary nitrifying trickling filters (NTFs) at the Littleton/Englewood wastewater treatment plant provide for nitrification to meet seasonally varying effluent requirements for ammonia nitrogen. Operation of the full-scale facilities during the past two years demonstrates highly efficient oxidation of ammonia and the effectiveness of biofilm control strategies. A decline in nitrification performance caused by predators was successfully corrected by the use of a special alkaline backwash feature which controlled the level of larval development within the NTFs.

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