scholarly journals Effect of Octenidine Hydrochloride on Planktonic Cells and Biofilms of Listeria monocytogenes

2009 ◽  
Vol 75 (12) ◽  
pp. 4089-4092 ◽  
Author(s):  
Mary Anne Roshni Amalaradjou ◽  
Carol E. Norris ◽  
Kumar Venkitanarayanan
Keyword(s):  
Stainless Steel ◽  
Organic Matter ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Planktonic Cells ◽  
Food Borne ◽  
Dry Milk ◽  
Presence And Absence ◽  
Nonfat Dry Milk

ABSTRACT Listeria monocytogenes is a food-borne pathogen capable of forming biofilms and persisting in food processing environments for extended periods of time, thereby potentially contaminating foods. The efficacy of octenidine hydrochloride (OH) for inactivating planktonic cells and preformed biofilms of L. monocytogenes was investigated at 37, 21, 8, and 4°C in the presence and absence of organic matter (rehydrated nonfat dry milk). OH rapidly killed planktonic cells and biofilms of L. monocytogenes at all four temperatures. Moreover, OH was equally effective in killing L. monocytogenes biofilms on polystyrene and stainless steel matrices in the presence and absence of organic matter. The results underscore OH's ability to prevent establishment of L. monocytogenes biofilms by rapidly killing planktonic cells and to eliminate preformed biofilms, thus suggesting that it could be used as a disinfectant to prevent L. monocytogenes from persisting in food processing environments.

Biofilm Formation and Associated Genes in Listeria Monocytogenes

2017 ◽  
Vol 12 (3) ◽  
Author(s):  
S. R. Warke ◽  
V. C. Ingle ◽  
N. V. Kurkure ◽  
P. A. Tembhurne ◽  
Minakshi Prasad ◽  
...  
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Multiplex Pcr ◽  
Food Processing ◽  
Biofilm Formation ◽  
Milk Samples ◽  
Biofilm Production ◽  
Food Borne ◽  
Serious Infections ◽  
Microtiter Assay

Listeria monocytogenes, an opportunistic food borne pathogen can cause serious infections in immunocompromised individuals. L. monocytogenes is capable of producing biofilm on the surface of food processing lines and instruments.The biofilm transfers contamination to food products and impose risk to public health. In the present study biofilm producing ability of L. monocytogenes isolates were investigated phenotypically and genotypically by microtiter assay and multiplex PCR, respectively. Out of 38 L. monocytogenes isolates 14 were recovered from animal clinical cases, 12 bovine environment and 12 from milk samples. A total of 3 (21.42%) clinical, 2 (16.66%) environment and 3 (25%) milk samples respectively, revealed biofilm production in microtiter assay. Cumulative results showed that 23 (60.52%) out of 38 strains of L. monocytogenes were positive for luxS and flaA gene and 1 (2.63%) was positive only for the flaA gene.

scholarly journals Effect of Gaseous Ozone on Listeria monocytogenes Planktonic Cells and Biofilm: An In Vitro Study

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1484
Author(s):  
Felice Panebianco ◽  
Selene Rubiola ◽  
Francesco Chiesa ◽  
Tiziana Civera ◽  
Pierluigi Aldo Di Ciccio
Keyword(s):  
Listeria Monocytogenes ◽  
In Vitro Study ◽  
Planktonic Cells ◽  
Free Living ◽  
Biofilm Inhibition ◽  
Additional Tool ◽  
Complete Inactivation ◽  
Gaseous Ozone ◽  
Food Borne

Among food-borne pathogens, Listeria monocytogenes continues to pose concerns to food business operators due to its capacity to form biofilm in processing environments. Ozone may be an eco-friendly technology to control microbial contaminations, but data concerning its effect on Listeria monocytogenes biofilm are still limited. In this study, the effect of gaseous ozone at 50 ppm on planktonic cells and biofilm of reference and food-related Listeria monocytogenes strains was evaluated. Ozone caused a reduction in microbial loads of 3.7 ± 0.4 and 3.9 ± 0.4 Log10 CFU/mL after 10 and 30 min, respectively. A complete inactivation of planktonic cells after 6 h of treatment was observed. Biofilm inhibition and eradication treatments (50 ppm, 6 h) resulted in a significant decrease of the biofilm biomass for 59% of the strains tested, whilst a slight dampening of live cell loads in the biofilm state was observed. In conclusion, gaseous ozone is not sufficient to completely counteract Listeria monocytogenes biofilm, but it may be useful as an additional tool to contrast Listeria monocytogenes free-living cells and to improve the existing sanitization procedures in food processing environments.

Chlorine Resistance of Listeria monocytogenes Biofilms and Relationship to Subtype, Cell Density, and Planktonic Cell Chlorine Resistance

2006 ◽  
Vol 69 (6) ◽  
pp. 1292-1296 ◽  
Author(s):  
JAMES P. FOLSOM ◽  
JOSEPH F. FRANK
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Cell Density ◽  
Sodium Hypochlorite ◽  
Resistance Mechanisms ◽  
Planktonic Cell ◽  
Planktonic Cells ◽  
Planktonic Culture

Strains of Listeria monocytogenes vary in their ability to produce biofilms. This research determined if cell density, planktonic chlorine resistance, or subtype are associated with the resistance of L. monocytogenes biofilms to chlorine. Thirteen strains of L. monocytogenes were selected for this research based on biofilm accumulation on stainless steel and rep-PCR subtyping. These strains were challenged with chlorine to determine the resistance of individual strains of L. monocytogenes. Planktonic cells were exposed to 20 to 80 ppm sodium hypochlorite in 20 ppm increments for 5 min in triplicate per replication, and the experiment was replicated three times. The number of tubes with surviving L. monocytogenes was recorded for each isolate at each level of chlorine. Biofilms of each strain were grown on stainless steel coupons. The biofilms were exposed 60 ppm of sodium hypochlorite. When in planktonic culture, four strains were able to survive exposure to 40 ppm of chlorine, whereas four strains were able to survive 80 ppm of chlorine in at least one of three tubes. The remaining five strains survived exposure to 60 ppm of chlorine. Biofilms of 11 strains survived exposure to 60 ppm of chlorine. No association of biofilm chlorine resistance and planktonic chlorine resistance was observed; however, biofilm chorine resistance was similar for strains of the same subtype. Biofilm cell density was not associated with chlorine resistance. In addition, biofilms that survived chlorine treatment exhibited different biofilm morphologies. These data suggest that chlorine resistance mechanisms of planktonic cells and biofilms differ, with planktonic chlorine resistance being more affected by inducible traits, and biofilm chlorine resistance being more affected by traits not determined in this study.

Survival of Listeria monocytogenes in Simulated Milk Cooling Systems1

1988 ◽  
Vol 51 (3) ◽  
pp. 172-175 ◽  
Author(s):  
R. PETRAN ◽  
E. A. ZOTTOLA
Keyword(s):  
Listeria Monocytogenes ◽  
Propylene Glycol ◽  
Water Systems ◽  
Cooling Systems ◽  
Dry Milk ◽  
Sweet Water ◽  
Minimal Media ◽  
Nonfat Dry Milk

Survival of Listeria monocytogenes under conditions that might be found in milk cooling systems was studied. Sterile solutions of 0.1 and 0.01% peptone, 0.1 and 0.01% nonfat dry milk (NFDM), 30% propylene glycol, and 30% propylene glycol with 0.01 % NFDM were inoculated with 6000 L. monocytogenes Scott A/ml and were incubated at 4°C. The temperature was increased to 7°C when little growth was observed. At 7°C, populations approached 109 organisms/ml in NFDM and peptone. Growth was greater in the higher concentrations of each, and there was limited survival in the glycol media. Growth in minimal media, 0.01% peptone, 0.01% NFDM, 30% propylene glycol with 0.01% NFDM, and 1 % tryptic soy broth (TSB), was studied. These media were inoculated with 3500 L. monocytogenes Jalisco cheese/ml. At 4°C, more growth was observed in the NFDM than in the peptone, no survival was seen in the glycol media, and the most growth was observed in the TSB. Growth in sterile 10, 20, and 30% propylene glycol solutions (with 0.1 % NFDM) was studied by inoculation with 8800 L. monocytogenes Jalisco cheese/ml and incubation at 4°C. Growth in the 10% solution was observed. However, there was survival in the 20 and 30% solutions with no increase in numbers apparent over the time studied. Presence of L. monocytogenes in milk cooling systems may pose a hazard, especially in sweet water systems that might contain a small amount of milk.

scholarly journals Variable Adhesion of Listeria monocytogenes Isolates from Food-Processing Facilities and Clinical Cases to Inert Surfaces

2007 ◽  
Vol 70 (7) ◽  
pp. 1569-1578 ◽  
Author(s):  
ODILE TRESSE ◽  
KELLY SHANNON ◽  
ANTHONY PINON ◽  
PIERRE MALLE ◽  
MICHÈLE VIALETTE ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Microtiter Plate ◽  
Clinical Strains ◽  
Microtiter Plates ◽  
Industrial Strains ◽  
Cheese Industry ◽  
Adhesion Rate ◽  
Inert Surfaces

One hundred one strains of Listeria monocytogenes isolated from seafood and cheese industry samples and from patients with listeriosis were assessed using a microtiter plate method for adhesion to polystyrene and stainless steel surfaces. The adhesion rate for these strains ranged from 3.10 to 35.29% with an inoculum of 8 × 108 cells per well. A strong correlation was found between adhesion to polystyrene and stainless steel microtiter plates, indicating that the intrinsic ability of L. monocytogenes to adhere to inert surfaces is stronger than the influence of the surface's physicochemical properties. The clinical strains were less adherent to inert surfaces than were the industrial strains. By integrating other factors such as location of the industrial strains, contamination type of the clinical strains, serotype, and pulsotype into the analysis, some weak but significant differences were noted. For the industrial isolates, the number of cells attached to both surfaces differed significantly depending on whether they were isolated from food or food-processing environments in the seafood and cheese industry. For clinical isolates, sporadic strains exhibited greater adhesion to polystyrene than did epidemic strains. Strains belonging to the pulsed-field gel electrophoretype clusters A and M (lineages II and I, respectively) were less able to adhere to polystyrene and stainless steel than were strains in the more common clusters.

Growth of Listeria monocytogenes as a Biofilm on Various Food-Processing Surfaces

1996 ◽  
Vol 59 (8) ◽  
pp. 827-831 ◽  
Author(s):  
ISABEL C. BLACKMAN ◽  
JOSEPH F. FRANK
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Biofilm Formation ◽  
Minimal Medium ◽  
Processing Plant ◽  
Biofilm Growth ◽  
Sanitary Condition ◽  
Plant Environment ◽  
Substantial Risk

The objective of this research was to determine the ability of Listeria monocytogenes to grow as a biofilm on various food-processing surfaces including stainless steel, Teflon®, nylon, and polyester floor sealant. Each of these surfaces was able to support biofilm formation when incubation was at 21°C in Trypticase soy broth (TSB). Biofilm formation was greatest on polyester floor sealant (40% of surface area covered after 7 days of incubation) and least on nylon (3% coverage). The use of chemically defined minimal medium resulted in a lack of biofilm formation on polyester floor sealant, and reduced biofilm levels on stainless steel. Biofilm formation was reduced with incubation at 10°C, but Teflon® and stainless steel still allowed 23 to 24% coverage after incubation in TSB for 18 days. Biofilm growth of L. monocytogenes was sufficient to provide a substantial risk of this pathogen contaminating the food-processing plant environment if wet surfaces are not maintained in a sanitary condition.

Effect of Time, Temperature and Transport Media on the Recovery of Listeria monocytogenes from Environmental Swabs

2020 ◽  
Author(s):  
Diana Stewart ◽  
Yadwinder Singh Rana ◽  
Kaiping Deng ◽  
Geethaanjali Vijayakumar ◽  
Lanlan Yin ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Logistic Regression ◽  
Listeria Monocytogenes ◽  
Sodium Hypochlorite ◽  
Food Processing ◽  
Storage Time ◽  
Cheese Whey ◽  
Storage Temperature ◽  
Food Matrix ◽  
Processing Facility

Environmental monitoring for Listeria monocytogenes in food processing environments is key for ensuring the safety of ready-to-eat foods. For sampling, swabs are often hydrated with a wetting or transport medium which may contain neutralizers and other ingredients. After swabbing the environment, the swabs may then be transported or shipped cold to an off-site laboratory for testing, ideally within 48 h. Extended shipping times may subject the pathogen to increased temperatures in the presence of the wetting medium, organics, and other chemicals from the processing facility which may confound detection. This study evaluated growth and detection of L. monocytogenes on stainless steel exposed to either buffer or sodium hypochlorite prior to drying. Swabs were rehydrated with Butterfield’s Phosphate Buffer, Neutralizing Buffer, Letheen Broth or Dey-Engley Neutralizing Broth prior to swabbing. Swabs were stored in the presence of no added food, cheese whey or ice cream under both optimal (4°) and sub-optimal (15°C) temperatures for up to 72 h. Overall, there was no growth of L. monocytogenes at 4°C through 72 h storage, though enrichment from these swabs was dependent on the presence and type of food matrix. Pathogen growth during storage at 15°C was more variable and depended on both the food matrix and transport media used, with Dey-Engley and Letheen Broth allowing for the highest population increases. Overall, more enrichments resulting in L. monocytogenes detections were observed when using Letheen Broth and Neutralizing Buffer than Dey-Engley which resulted in fewer detections at 15°C. Logistic regression and Cochran-Mantel-Haenszel (CMH) analyses determined that storage temperature, transport media, and food matrix all significantly affected detection of L. monocytogenes , while storage time did not have a clear effect on recovery from swabs.

scholarly journals Evaluation of the efficacy of commercial sanitizers against adhered and planktonic cells of Listeria monocytogenes and Salmonella spp.

2012 ◽  
Vol 32 (3) ◽  
pp. 606-612 ◽  
Author(s):  
Julia Carballo ◽  
Ana-Belén Araújo
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Industry ◽  
Pathogenic Bacteria ◽  
Antimicrobial Activities ◽  
Planktonic Cells ◽  
Salmonella Spp ◽  
Planktonic Bacteria ◽  
Attached Bacteria ◽  
Ammonium Compounds

Antimicrobial activities of two commercial disinfectants, alone or combined with heat, against three Salmonella strains and three Listeria monocytogenes strains were studied. The efficacy of disinfectants against planktonic bacteria and bacteria attached to three food contact industrial surfaces (stainless steel, polytetraflourethylene, and rubber) was investigated. The tests were conducted using the sanitizer (quaternary ammonium compounds, and alquyldiethylenediamineglycine and di-alquyldiamineethylglycine) concentrations recommended by the manufacturers, and concentrations twice and four times higher than those values. The recommended concentrations were not effective to kill bacteria, especially when they were attached to surfaces. Concentrations of disinfectants twice and four times higher than those recommended were needed to fully eliminate planktonic bacteria. These same sanitizer concentrations were not sufficient to remove attached bacteria. To remove them from the surfaces, a treatment with recommended concentrations in combination with heat was needed. Our results indicate that these two pathogenic bacteria could survive common sanitation programs used in the food industry.

Survival of Listeria monocytogenes During the Manufacture and Storage of Nonfat Dry Milk

1985 ◽  
Vol 48 (9) ◽  
pp. 740-742 ◽  
Author(s):  
MICHAEL P. DOYLE ◽  
LOUISE M. MESKE ◽  
ELMER H. MARTH
Keyword(s):  
Listeria Monocytogenes ◽  
Spray Drying ◽  
Skim Milk ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Drying Process ◽  
Dry Milk ◽  
Nonfat Dry Milk ◽  
And Storage ◽  
Moisture Resistant

The ability of Listeria monocytogenes to survive in skim milk during spray drying and to persist in nonfat dry milk during storage was examined. Concentrated (30% solids) and unconcentrated skim milks were inoculated with ca. 105 to 106 L. monocytogenes/ml and spray dried (inlet temperature, 165 ± 2°C; outlet temperature 67 ± 2°C) to a moisture content of 3.6 to 6.4%. The nonfat dry milk was packaged in moisture-resistant film and stored at 25°C for up to 16 wk. A reduction of ca. 1 to 1.5 log10 L. monocytogenes/g occurred during the spray drying process, irrespective of whether the milk was concentrated or not before spray drying. The organism progressively died during storage at 25°C, with a >4-log10 CFU/g decrease occurring within 16 wk of storage.

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