Inactivation of Listeria monocytogenes by Disinfectants and Bacteriophages in Suspension and Stainless Steel Carrier Tests

2014 ◽  
Vol 77 (12) ◽  
pp. 2012-2020 ◽  
Author(s):  
N. CHAITIEMWONG ◽  
W. C. HAZELEGER ◽  
R. R. BEUMER
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Quaternary Ammonium ◽  
Antimicrobial Effect ◽  
Quaternary Ammonium Compound ◽  
Steel Plates ◽  
Ammonium Compound ◽  
Standard Requirement ◽  
Sodium Dichloroisocyanurate ◽  
Food Residues

To simulate food contact surfaces with pits or cracks, stainless steel plates with grooves (depths between 0.2 and 5 mm) were constructed. These plates were artificially contaminated with Listeria monocytogenes in clean conditions, with organic soiling, or after 14 days of biofilm formation after which inactivation of the pathogen by Suma Tab D4 (sodium dichloroisocyanurate, 240 and 300 mg/liter), Suma Bac D10 (quaternary ammonium compound, 740 mg/liter), and bacteriophage suspension (Listex P100) was determined. Both chemical disinfectants performed well in suspension tests and in clean carrier tests according to the European standard with a reduction of more than 5 and 4 log units, respectively, of Listeria cells after 5 min of contact time. However, for the plates with grooves, the reduction could not meet the standard requirement, although a higher reduction of L. monocytogenes was observed in the shallow grooves compared with the deeper grooves. Furthermore, presence of food residues and biofilm reduced the effect of the disinfectants especially in the deep grooves, which was dependent on type of food substrate. Bacteriophages showed the best antimicrobial effect compared with the chemical disinfectants (sodium dichloroisocyanurate and quaternary ammonium compound) in most cases in the shallow grooves, but not in the deep grooves. The chlorine based disinfectants were usually less effective than quaternary ammonium compound. The results clearly demonstrate that surfaces with grooves influenced the antimicrobial effect of the chemical disinfectants and bacteriophages because the pathogen is protected in the deep grooves. The use of bacteriophages to inactivate pathogens on surfaces could be helpful in limited cases; however, use of large quantities in practice may be costly and phage-resistant strains may develop.

scholarly journals Transfer of Persistent Listeria monocytogenes Contamination between Food-Processing Plants Associated with a Dicing Machine

2002 ◽  
Vol 65 (7) ◽  
pp. 1129-1133 ◽  
Author(s):  
JANNE M. LUNDÉN ◽  
TIINA J. AUTIO ◽  
HANNU J. KORKEALA
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Sodium Hypochlorite ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Compound ◽  
Pfge Type ◽  
Ammonium Compound ◽  
Type I ◽  
Minimal Inhibitory Concentrations ◽  
Steel Surfaces

The possibility of the transfer of persistent Listeria monocytogenes contamination from one plant to another with a dicing machine was evaluated, and possible reasons for persistent contamination were analyzed. A dicing machine that diced cooked meat products was transferred from plant A to plant B and then to plant C. After the transfer of the dicing machine, L. monocytogenes PFGE type I, originally found in plant A, was soon also found in plants B and C. This L. monocytogenes PFGE type I caused persistent contamination of the dicing lines in plants B and C. The persistent L. monocytogenes strain and three nonpersistent L. monocytogenes strains found in the dicing line of plant C were tested for adherence to stainless steel surfaces and minimal inhibitory concentrations of a quaternary ammonium compound and sodium hypochlorite, disinfectants widely used in the dicing lines. The persistent strain showed significantly higher adherence to stainless steel surfaces than did the nonpersistent strains. The minimal inhibitory concentrations of sodium hypochlorite were similar for all strains, and the minimal inhibitory concentrations of the quaternary ammonium compound for three of the L. monocytogenes PFGE types, including the persistent PFGE type, were high. All persistent L. monocytogenes PFGE type I isolates were found in an area with high hygienic standards, with the dicing machine being the first point of contamination. These observations show that the dicing machine sustained the contamination and suggest that the dicing machine transferred the persistent L. monocytogenes PFGE type from one plant to another.

scholarly journals Comparison of three neutralizing broths for environmental sampling of low levels of Listeria monocytogenes desiccated on stainless steel surfaces and exposed to quaternary ammonium compounds

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Fengmin Li ◽  
Zhihan Xian ◽  
Hee Jin Kwon ◽  
Jiyoon Yoo ◽  
Laurel Burall ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Quaternary Ammonium ◽  
Storage Conditions ◽  
Ammonium Compound ◽  
Environmental Sampling ◽  
High Concentration ◽  
Environmental Test ◽  
Steel Surfaces ◽  
Low Levels

Abstract Background An effective environmental sampling method involves the use of a transport/neutralizing broth with the ability to neutralize sanitizer residues that are collected during sampling and to maintain viability of stressed Listeria monocytogenes (Lm) cells. Results We applied Lm onto stainless steel surfaces and then subjected Lm to desiccation stress for 16–18 h at room temperature (RT, 21–24 °C). This was followed by the subsequent application of Whisper™ V, a quaternary ammonium compound (QAC)-based sanitizer, diluted to 400 ppm and 8000 ppm of active quat, for 6 h. We then sampled Lm with sponges pre-moistened in three transport broths, Dey/Engley (D/E) broth, Letheen broth and HiCap™ broth, to generate environmental samples that contained sanitizer residues and low levels of stressed Lm, which were subsequently analyzed by an enrichment-based method. This scheme conformed with validation guidelines of AOAC International by using 20 environmental test portions per broth that contained low levels of Lm such that not all test portions were positive (i.e., fractional positive). We showed that D/E broth, Letheen broth and HiCap™ broth performed similarly when no quat or 400 ppm of quat was applied to the Lm contaminating stainless steel surfaces. However, when 8000 ppm of quat was applied, Letheen broth did not effectively neutralize the QAC in the samples. These comparisons were performed on samples stored under three conditions after collection to replicate scenarios of sample transport, RT for 2 h, 4 °C for 24 h and 4 °C for 72 h. Comparisons under the three different scenarios generally reached the same conclusions. In addition, we further demonstrated that storing Letheen and HiCap™ broths at RT for two months before sampling did not reduce their capacity to neutralize sanitizers. Conclusions We developed a scheme to evaluate the ability of transport broths to neutralize QAC sanitizers. The three transport broths performed similarly with a commonly used concentration of quat, but Letheen broth could not effectively neutralize a very high concentration of QAC. The performance of transport broths was not significantly affected under the assessed pre-sampling and post-sampling storage conditions.

Destruction of Listeria monocytogenes by Sodium Hypochlorite and Quaternary Ammonium Sanitizers

1989 ◽  
Vol 52 (5) ◽  
pp. 306-311 ◽  
Author(s):  
A. MUSTAPHA ◽  
M. B. LIEWEN
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Sodium Hypochlorite ◽  
Quaternary Ammonium ◽  
Ammonium Compound ◽  
Electron Microscopic ◽  
Acidic Polysaccharide ◽  
Scanning Electron Microscopic ◽  
Dairy Plant

The antimicrobial effects of two commonly used dairy plant sanitizers on Listeria monocytogenes ATCC 7644 were studied. The two sanitizers used were commercial sodium hypochlorite and quaternary ammonium compound (QAC). The effects were studied on L. monocytogenes in vitro and on stainless steel chips inoculated with the organism. Cells were exposed to concentrations of 0, 50, 100, 200, 400, and 800 ppm chlorine and QAC for 1, 2, and 5 minutes, and neutralized with tryptic soy broth. Decreases in cell numbers ranged from 3-logs to >4-logs in vitro, whereas with the stainless steel, it ranged from 1-log to >4-logs. Scanning electron microscopic (SEM) studies were done to evaluate the attachment characteristics of L. monocytogenes as compared to those of Escherichia coli on stainless steel. L. monocytogenes was found to produce a fibrous-like material similar in appearance to acidic polysaccharide fibrils produced by Pseudomonas sp., which appeared to be removed by the sanitizer solutions.

Effectiveness of Sanitation with Quaternary Ammonium Compound or Chlorine on Stainless Steel and Other Domestic Food-Preparation Surfaces

1997 ◽  
Vol 60 (1) ◽  
pp. 43-47 ◽  
Author(s):  
JOSEPH F. FRANK ◽  
REVIS A. N. CHMIELEWSKI
Keyword(s):  
Stainless Steel ◽  
Quaternary Ammonium ◽  
Test Procedure ◽  
Food Service ◽  
Quaternary Ammonium Compound ◽  
Ammonium Compound ◽  
Relative Ability ◽  
Polished Stainless Steel ◽  
Materials Used ◽  
Type 304

The relative ability of various materials used for domestic and/or food-service sinks and countertops to be sanitized was determined. Both smooth (unused) and abraded surfaces were tested by exposure to 200 mg of quaternary ammonium compound per liter or 200 mg of sodium hypochlorite per liter. Surface materials tested included mechanically polished (type 304, #4 finish) and electropolished stainless steel, polycarbonate, and mineral resin. Surfaces were prepared for testing by allowing attachment of a Staphylococcus aureus culture for 4 h to achieve an initial attached population of 104 to 105 CFU/cm2. The test procedure involved immersion of the surface in sanitizer solution followed by wiping with a sanitizer-saturated cloth. Residual staphylococci were detected by overlaying agar directly on the treated surface. Results indicated that the stainless steels and the smooth polycarbonate, which had 0.5 log CFU/cm2 or fewer of residual staphylococci, were more readily sanitized by quaternary ammonium compound than were either the mineral resin surfaces, which had nearly 2.0 log CFU/cm2 of residual staphylococci, or the abraded polycarbonate which had nearly 1.0 log CFU/cm2 of residual staphylococci. Chlorine was most effective on the mechanically polished stainless steel, the unabraded electropolished stainless steel, and the polycarbonate surfaces, reducing cell populations to less than 1.0 log CFU/cm2. Chlorine was less effective on abraded electropolished stainless steel and mineral resin surfaces, where populations remained greater than 1.0 log CFU/cm2. Sanitation with quaternary ammonium compound or chlorine reduced S. aureus populations more than 1,000-fold on all surfaces except unabraded mineral resin.

Inactivation of Yersinia pseudotuberculosis, as a Surrogate for Yersinia pestis, by Liquid Biocides in the Presence of Food Residue

2009 ◽  
Vol 72 (2) ◽  
pp. 392-398 ◽  
Author(s):  
J. HILGREN ◽  
K. M. J. SWANSON ◽  
F. DIEZ-GONZALEZ ◽  
B. CORDS
Keyword(s):  
Quaternary Ammonium ◽  
Yersinia Pseudotuberculosis ◽  
Test Organism ◽  
Egg Yolk ◽  
Quaternary Ammonium Compound ◽  
Acid Mixture ◽  
Sodium Chlorite ◽  
Ammonium Compound ◽  
Peroxyacetic Acid ◽  
Food Residues

The efficacy of liquid biocides is influenced by surface cleanliness, treatment time, and temperature. Experiments were completed to measure the impact of these variables on the ability of commercial biocides to inactivate Yersinia pseudotuberculosis ATCC 29910, as a surrogate for Yersinia pestis, in the presence of food residues. The test organism was mixed with water, milk, flour, or egg yolk and then dried onto stainless steel coupons. Coupons were then exposed to sodium hypochlorite, acidified sodium chlorite, a quaternary ammonium compound, an iodophor, hydrogen peroxide, peroxyacetic acid, or a peroxy–fatty acid mixture, for 10 or 30 min at 10, 20, or 30°C. For all biocides except the iodophor, manufacturer-recommended disinfection levels applied for 10 min at 20°C resulted in 5-log reductions of the test organism dried alone or with flour. However, in the presence of whole milk or egg yolk residue, markedly higher sodium hypochlorite, peroxyacetic acid, peroxy–fatty acid mixture, quaternary ammonium compound, and iodophor concentrations were needed to achieve the 5-log reductions. Further, the quaternary ammonium compound was incapable of achieving 5-log reductions in 10 min in the presence of milk and egg yolk residues. Hydrogen peroxide and acidified sodium chlorite disinfection levels (7.5% and 2,500 ppm, respectively) achieved 5-log reductions under all test conditions. These results suggest that commercial disinfectants can adequately decontaminate clean surfaces contaminated with Y. pseudotuberculosis and Y. pestis. These results also provide guidance on the feasibility of overcoming the negative influence of food residues on disinfection by adjusting biocide exposure time, temperature, and concentration.

scholarly journals Genetic Subtyping, Biofilm-Forming Ability and Biocide Susceptibility of Listeria monocytogenes Strains Isolated from a Ready-to-Eat Food Industry

Antibiotics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 416
Author(s):  
Joana Catarina Andrade ◽  
António Lopes João ◽  
Carlos de Sousa Alonso ◽  
António Salvador Barreto ◽  
Ana Rita Henriques
Keyword(s):  
Listeria Monocytogenes ◽  
Quaternary Ammonium ◽  
Benzalkonium Chloride ◽  
Food Industry ◽  
Raw Materials ◽  
Foodborne Pathogen ◽  
Positive Association ◽  
Quaternary Ammonium Compound ◽  
Ammonium Compound ◽  
Food Grade

Listeria monocytogenes is a foodborne pathogen of special concern for ready-to-eat food producers. The control of its presence is a critical step in which food-grade sanitizers play an essential role. L. monocytogenes is believed to persist in food processing environments in biofilms, exhibiting less susceptibility to sanitizers than planktonic cells. This study aimed to test the susceptibility of L. monocytogenes in planktonic culture and biofilm to three commercial food-grade sanitizers and to benzalkonium chloride; together with the genetic subtyping of the isolates. L. monocytogenes isolates were collected from raw materials, final products and food-contact surfaces during a 6-year period from a ready-to-eat meat-producing food industry and genetically characterized. Serogrouping and pulsed-field gel electrophoresis (PFGE) revealed genetic variability and differentiated L. monocytogenes isolates in three clusters. The biofilm-forming ability assay revealed that the isolates were weak biofilm producers. L. monocytogenes strains were susceptible both in the planktonic and biofilm form to oxidizing and ethanol-based compounds and to benzalkonium chloride, but not to quaternary ammonium compound. A positive association of biofilm-forming ability and LD90 values for quaternary ammonium compound and benzalkonium chloride was found. This study highlights the need for preventive measures improvement and for a conscious selection and use of sanitizers in food-related environments to control Listeria monocytogenes.

Sensitivity of Listeria monocytogenes to Sanitizers after Exposure to a Chemical Shock

1996 ◽  
Vol 59 (4) ◽  
pp. 374-378 ◽  
Author(s):  
EUREKA L. PICKETT ◽  
ELSA A. MURANO
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Inhibitory Concentration ◽  
Quaternary Ammonium Compound ◽  
Ammonium Compound ◽  
Ph Adjustment ◽  
Lethal Level ◽  
Significant Difference ◽  
Subsequent Exposure ◽  
Steel Surfaces

We tested the hypothesis that exposure of Listeria monocytogenes to sublethal levels of sanitizers (chemical shock) could affect survival to a subsequent exposure to lethal levels and the ability of the cells to attach to stainless steel surfaces. L. monocytogenes was exposed to an acidic anionic sanitizer, a chlorine-based sanitizer, an iodophor, and a quaternary ammonium compound, as well as to citric, lactic, and propionic acids. The cells were exposed to sublethal levels of each sanitizer for up to 60 min (chemical shock), followed by exposure to either the minimum inhibitory concentration (MIC) for 48 h, to the lethal level for 48 h, or to the MIC for 40 min followed by the lethal level for 48 h. No significant difference in survival was observed with most of the sanitizers used. However, exposure to a chemical shock with the acid anionic sanitizer for at least 10 min resulted in survival of the cells in the MIC of this sanitizer, as well as in the lethal level, but only when the cells were first exposed to the MIC for 40 min. Deliberate dissociation of citric acid by pH adjustment also resulted in survival of chemically shocked cells to lethal levels of this acid, suggesting that exposure to the dissociated form somehow enabled cells to survive exposure to lethal levels of the acid. Chemical shock did not affect attachment of the cells to stainless-steel chips.

scholarly journals Tolerance to quaternary ammonium compound disinfectants may enhance growth of Listeria monocytogenes in the food industry

2017 ◽  
Vol 241 ◽  
pp. 215-224 ◽  
Author(s):  
Trond Møretrø ◽  
Bjørn C.T. Schirmer ◽  
Even Heir ◽  
Annette Fagerlund ◽  
Pernille Hjemli ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Quaternary Ammonium ◽  
Food Industry ◽  
Quaternary Ammonium Compound ◽  
Ammonium Compound

scholarly journals Adaptation to a Commercial Quaternary Ammonium Compound Sanitizer Leads to Cross-Resistance to Select Antibiotics in Listeria monocytogenes Isolated From Fresh Produce Environments

2022 ◽  
Vol 12 ◽  
Author(s):  
Rebecca Bland ◽  
Joy Waite-Cusic ◽  
Alexandra J. Weisberg ◽  
Elizabeth R. Riutta ◽  
Jeff H. Chang ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Quaternary Ammonium ◽  
Efflux Pump ◽  
Fresh Produce ◽  
Genomic Analysis ◽  
Quaternary Ammonium Compound ◽  
Cross Resistance ◽  
Comparative Genomic ◽  
Ammonium Compound ◽  
Efflux Pump Inhibitor

The effective elimination of Listeria monocytogenes through cleaning and sanitation is of great importance to the food processing industry. Specifically in fresh produce operations, the lack of a kill step requires effective cleaning and sanitation to mitigate the risk of cross-contamination from the environment. As facilities rely on sanitizers to control L. monocytogenes, reports of the development of tolerance to sanitizers and other antimicrobials through cross-resistance is of particular concern. We investigated the potential for six L. monocytogenes isolates from fresh produce handling and processing facilities and packinghouses to develop cross-resistance between a commercial sanitizer and antibiotics. Experimental adaptation of isolates belonging to hypervirulent clonal complexes (CC2, CC4, and CC6) to a commercial quaternary ammonium compound sanitizer (cQAC) resulted in elevated minimum inhibitory concentrations (2–3 ppm) and minimum bactericidal concentrations (3–4 ppm). Susceptibility to cQAC was restored for all adapted (qAD) isolates in the presence of reserpine, a known efflux pump inhibitor. Reduced sensitivity to 7/17 tested antibiotics (chloramphenicol, ciprofloxacin, clindamycin, kanamycin, novobiocin, penicillin, and streptomycin) was observed in all tested isolates. qAD isolates remained susceptible to antibiotics commonly used in the treatment of listeriosis (i.e., ampicillin and gentamicin). The whole genome sequencing of qAD strains, followed by comparative genomic analysis, revealed several mutations in fepR, the regulator for FepA fluoroquinolone efflux pump. The results suggest that mutations in fepR play a role in the reduction in antibiotic susceptibility following low level adaptation to cQAC. Further investigation into the cross-resistance mechanisms and pressures leading to the development of this phenomenon among L. monocytogenes isolates recovered from different sources is needed to better understand the likelihood of cross-resistance development in food chain isolates and the implications for the food industry.

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