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.

scholarly journals The Listeria monocytogenes Homolog of the Escherichia coli era Gene Is Involved in Adhesion to Inert Surfaces

2007 ◽  
Vol 73 (23) ◽  
pp. 7789-7792 ◽  
Author(s):  
Frédéric Auvray ◽  
Danielle Chassaing ◽  
Cécile Duprat ◽  
Brigitte Carpentier
Keyword(s):  
Escherichia Coli ◽  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Growth Defect ◽  
Cell Populations ◽  
Lower Growth ◽  
E Coli ◽  
Attached Cell ◽  
Dimethylammonium Chloride ◽  
Inert Surfaces

ABSTRACT Two transposon-insertional mutants of Listeria monocytogenes showing smaller viable surface-attached cell populations after disinfection with N,N-didecyl-N,N-dimethylammonium chloride were identified. In both mutants, transposon Tn917-lac was found to be inserted into the same gene, lmo1462, which is homologous to the essential Escherichia coli era gene. Both L. monocytogenes lmo1462-disrupted mutants displayed lower growth rates, as was also shown for several E. coli era mutants, and the lmo1462 gene was able to complement the growth defect of an E. coli era mutant. We showed that the disruption of lmo1462 decreased the ability of L. monocytogenes cells to adhere to stainless steel. Our results suggest that this era-like gene is involved in adhesion and contributes to the presence of L. monocytogenes on surfaces.

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 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.

scholarly journals Listeria monocytogenes Attachment to and Detachment from Stainless Steel Surfaces in a Simulated Dairy Processing Environment

2009 ◽  
Vol 75 (22) ◽  
pp. 7182-7188 ◽  
Author(s):  
Sofia Poimenidou ◽  
Charalambia A. Belessi ◽  
Efstathios D. Giaouris ◽  
Antonia S. Gounadaki ◽  
George-John E. Nychas ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Dairy Products ◽  
Pasteurized Milk ◽  
Fresh Milk ◽  
Dairy Processing ◽  
Two Temperatures ◽  
Steel Surfaces ◽  
Suspended Cells

ABSTRACT The presence of pathogens in dairy products is often associated with contamination via bacteria attached to food-processing equipment, especially from areas where cleaning/sanitation is difficult. In this study, the attachment of Listeria monocytogenes on stainless steel (SS), followed by detachment and growth in foods, was evaluated under conditions simulating a dairy processing environment. Initially, SS coupons were immersed in milk, vanilla custard, and yogurt inoculated with the pathogen (107 CFU/ml or CFU/g) and incubated at two temperatures (5 and 20�C) for 7 days. By the end of incubation, cells were mechanically detached from coupons and used to inoculate freshly pasteurized milk which was subsequently stored at 5�C for 20 days. The suspended cells in all three products in which SS coupons were immersed were also used to inoculate freshly pasteurized milk (5�C for 20 days). When SS coupons were immersed in milk, shorter lag phases were obtained for detached than for planktonically grown cells, regardless of the preincubation temperature (5 or 20�C). The opposite was observed when custard incubated at 20�C was used to prepare the two types of inocula. However, in this case, a significant increase in growth rate was also evident when the inoculum was derived from detached cells. In another parallel study, while L. monocytogenes was not detectable on SS coupons after 7 days of incubation (at 5�C) in inoculated yogurt, marked detachment and growth were observed when these coupons were subsequently transferred and incubated at 5�C in fresh milk or/and custard. Overall, the results obtained extend our knowledge on the risk related to contamination of dairy products with detached L. monocytogenes cells.

scholarly journals Resistance of Listeria monocytogenes Biofilms to Sanitizing Agents in a Simulated Food Processing Environment

2006 ◽  
Vol 72 (12) ◽  
pp. 7711-7717 ◽  
Author(s):  
Y. Pan ◽  
F. Breidt ◽  
S. Kathariou
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Extracellular Polymeric Substances ◽  
Control Treatment ◽  
Daily Cycles ◽  
Sterile Plastic ◽  
And Control ◽  
Ammonium Compounds ◽  
Food Processing Environment

ABSTRACT The objective of this study was to evaluate the resistance of biofilms of Listeria monocytogenes to sanitizing agents under laboratory conditions simulating a food processing environment. Biofilms were initially formed on stainless steel and Teflon coupons using a five-strain mixture of L. monocytogenes. The coupons were then subjected to repeated 24-h daily cycles. Each cycle consisted of three sequential steps: (i) a brief (60 s) exposure of the coupons to a sanitizing agent (a mixture of peroxides) or saline as a control treatment, (ii) storage of the coupons in sterile plastic tubes without any nutrients or water for 15 h, (iii) and incubation of the coupons in diluted growth medium for 8 h. This regimen was repeated daily for up to 3 weeks and was designed to represent stresses encountered by bacteria in a food processing environment. The bacteria on the coupons were reduced in number during the first week of the simulated food processing (SFP) regimen, but then adapted to the stressful conditions and increased in number. Biofilms repeatedly exposed the peroxide sanitizer in the SFP regimen developed resistance to the peroxide sanitizer as well as other sanitizers (quaternary ammonium compounds and chlorine). Interestingly, cells that were removed from the biofilms on peroxide-treated and control coupons were not significantly different in their resistance to sanitizing agents. These data suggest that the resistance of the treated biofilms to sanitizing agents may be due to attributes of extracellular polymeric substances and is not an intrinsic attribute of the cells in the biofilm.

Reduction of Listeria monocytogenes Biofilms on Stainless Steel and Polystyrene Surfaces by Essential Oils†

2012 ◽  
Vol 75 (7) ◽  
pp. 1332-1337 ◽  
Author(s):  
MONIL A. DESAI ◽  
KAMLESH A. SONI ◽  
RAMAKRISHNA NANNAPANENI ◽  
M. WES SCHILLING ◽  
JUAN L. SILVA
Keyword(s):  
Antimicrobial Activity ◽  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Essential Oils ◽  
Thyme Oil ◽  
Microtiter Plates ◽  
Disk Diffusion Assay ◽  
Steel Surfaces ◽  
Oregano Oil ◽  
Diffusion Assay

Plant-derived essential oils were tested for their ability to eliminate biofilms of Listeria monocytogenes on polystyrene and stainless steel surfaces. Various concentrations of essential oils were tested with different contact times on biofilms of various ages. Preliminarily screening of nine essential oils and related phenolic compounds in a disk diffusion assay revealed that thyme oil, oregano oil, and carvacrol had the highest antimicrobial activity. Further screening of these three compounds against 21 L. monocytogenes strains representing all 13 serotypes indicated some strain-specific variations in antimicrobial activity. For 1-day-old biofilms of mixed L. monocytogenes strains produced at 22°C on polystyrene microtiter plates, only 0.1% concentrations of thyme oil, oregano oil, and carvacrol were needed to eliminate 7 log CFU per well. On the stainless steel coupons, a 0.5% concentration of these compounds was adequate to completely eliminate 4-day-old biofilms at 7 log CFU per coupon. Our findings indicate that these compounds are potential candidates for elimination of L. monocytogenes biofilms on stainless steel and polystyrene surfaces.

scholarly journals Antibiofilm Effects of Nanoparticles and Visible Light Illumination Against Listeria monocytogenes

2021 ◽  
Vol 12 ◽  
Author(s):  
Sanna Puranen ◽  
Kati Riekkinen ◽  
Jenni Korhonen
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Safety ◽  
Visible Light ◽  
Food Processing ◽  
Biofilm Formation ◽  
Plate Count ◽  
Light Illumination ◽  
Visible Light Illumination ◽  
Aluminum Plates

Listeria monocytogenes bacteria pose a particular risk to the food industry as the species is known to form biofilm and to survive in a wide range of challenging environmental conditions. L. monocytogenes can cause listeriosis, a serious food-borne disease, and effective and safe antibiofilm materials and sanitary methods for food processing environments are intensively sought. A variety of nanoparticle materials have been recognized as safe to use in food environments, which allows the application of nanomaterials also for food safety purposes. Nanoparticles together with light illumination generate reactive oxygen species which inactivate bacteria by breaking down cell membranes, proteins, and DNA. The main objective of this study was to evaluate the efficacy of nanomaterials and blue light illumination for L. monocytogenes ATCC 7644 biofilm inactivation. Biofilm was allowed to form for 72 h on nanocoated stainless steel and aluminum plates, after which the plates were illuminated. Non-coated control plates were used to evaluate the antibiofilm efficacy of nanocoating. Plate count method was used to evaluate bacteria counts after illumination. Nanocoating did not affect initial biofilm formation compared to the control plates. Biofilm was significantly (p < 0.05) reduced on stainless steel, aluminum, and TiO2-coated aluminum plates after 72-h illumination by 1.9, 3.2, and 5.9 log, respectively. Nanocoating with visible light illumination could be an effective and safe method for enhancing food safety in food processing facilities to control biofilm formation. Evidence of antibiofilm properties of nanomaterials together with visible light illumination is limited; hence, future studies with variable light intensities and nanomaterials are needed.

Survival of Listeria monocytogenes Attached to Stainless Steel Surfaces in the Presence or Absence of Flavobacterium spp.

2001 ◽  
Vol 64 (9) ◽  
pp. 1369-1376 ◽  
Author(s):  
PHILIP J. BREMER ◽  
IAN MONK ◽  
CAROLYN M. OSBORNE
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Mixed Culture ◽  
Cell Population ◽  
Exposure Time ◽  
Food Processing ◽  
Pure Culture ◽  
Bacterial Biofilm ◽  
Selective Agar ◽  
Steel Surfaces

Contaminated surfaces of food processing equipment are believed to be a significant source of Listeria monocytogenes to foods. However, very little is known about the survival of Listeria in processing environments. In a mixed bacterial biofilm of L. monocytogenes and Flavobacterium spp., the number of L. monocytogenes cells attaching to stainless steel increased significantly compared to when L. monocytogenes was in a pure culture. The L. monocytogenes cells in the mixed biofilms were also recoverable for significantly longer exposure periods. On colonized coupons held at 15°C and 75% humidity, decimal reduction times were 1.2 and 18.7 days for L. monocytogenes in pure and mixed biofilms, respectively. With increasing exposure time, the proportion of cells that were sublethally injured (defined as an inability to grow on selective agar) increased from 8.1% of the recoverable cell population at day 0 to 91.4% after 40 days' exposure. At 4 and −20°C, decimal reduction times for L. monocytogenes in pure culture were 2.8 and 1.4 days, respectively, and in mixed culture, 10.5 and 14.4 days, respectively. The enhanced colonization and survival of L. monocytogenes on “unclean” surfaces increase the persistence of this pathogen in food processing environments, while the increase in the percentage of sublethally injured cells in the population with time may decrease the ability of enrichment regimes to detect it.

Morphological Change and Decreasing Transfer Rate of Biofilm-Featured Listeria monocytogenes EGDe

2017 ◽  
Vol 80 (3) ◽  
pp. 368-375 ◽  
Author(s):  
Yuejia Lee ◽  
Chinling Wang
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Biofilm Formation ◽  
Transfer Rate ◽  
Initial Level ◽  
Foodborne Pathogen ◽  
Bacterial Growth Rate ◽  
Biofilm Development ◽  
Food Processing Environment

ABSTRACT Listeria monocytogenes, a lethal foodborne pathogen, has the ability to resist the hostile food processing environment and thus frequently contaminates ready-to-eat foods during processing. It is commonly accepted that the tendency of L. monocytogenes' to generate biofilms on various surfaces enhances its resistance to the harshness of the food processing environment. However, the role of biofilm formation in the transferability of L. monocytogenes EGDe remains controversial. We examined the growth of Listeria biofilms on stainless steel surfaces and their effect on the transferability of L. monocytogenes EGDe. The experiments were a factorial 2 × 2 design with at least three biological replicates. Through scanning electron microscopy, a mature biofilm with intensive aggregates of cells was observed on the surface of stainless steel after 3 or 5 days of incubation, depending on the initial level of inoculation. During biofilm development, L. monocytogenes EGDe carried out binary fission vigorously before a mature biofilm was formed and subsequently changed its cellular morphology from rod shaped to sphere shaped. Furthermore, static biofilm, which was formed after 3 days of incubation at 25°C, significantly inhibited the transfer rate of L. monocytogenes EGDe from stainless steel blades to 15 bologna slices. During 7 days of storage at 4°C, however, bacterial growth rate was not significantly impacted by whether bacteria were transferred from biofilm and the initial concentrations of transferred bacteria on the slice. In conclusion, this study is the first to report a distinct change in morphology of L. monocytogenes EGDe at the late stage of biofilm formation. More importantly, once food is contaminated by L. monocytogenes EGDe, contamination proceeds independently of biofilm development and the initial level of contamination when food is stored at 4°C, even if contamination with L. monocytogenes EGDe was initially undetectable before storage.

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