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.

Destruction of Listeria monocytogenes Biofilms on Stainless Steel Using Monolaurin and Heat1

1995 ◽  
Vol 58 (3) ◽  
pp. 251-255 ◽  
Author(s):  
DEOG-HWAN OH ◽  
DOUGLAS L. MARSHALL
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Industry ◽  
Adherent Cells ◽  
Planktonic Cells ◽  
Antimicrobial Effects ◽  
Biofilm Removal ◽  
Nutrient Environment ◽  
Physical Treatments

Individual and combined antimicrobial effects of monolaurin and heat on planktonic, 1-day adherent, or 7-day adherent cells of Listeria monocytogenes were determined to evaluate biofilm removal from stainless steel. Planktonic cells were more sensitive to heat and monolaurin than were cells attached to stainless steel. Young (1-day) biofilm cells were more sensitive to each treatment than were old (7-day) biofilm cells. Adherent cells were destroyed by 50 μg/ml monolaurin combined with heating at 65°C for 5 min. Cells in a rich nutrient environment were more resistant to treatment than were cells in a depleted nutrient environment. Results demonstrate the usefulness of combining chemical and physical treatments to control L. monocytogenes biofilm problems in the food industry.

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.

Antibacterial Effects of Long-Chain Polyphosphates on Selected Spoilage and Pathogenic Bacteria

2008 ◽  
Vol 71 (7) ◽  
pp. 1401-1405 ◽  
Author(s):  
JEREMY A. OBRITSCH ◽  
DOJIN RYU ◽  
LUCINA E. LAMPILA ◽  
LLOYD B. BULLERMAN
Keyword(s):  
Food Industry ◽  
Pathogenic Bacteria ◽  
Antimicrobial Activities ◽  
Lag Phase ◽  
E Coli ◽  
Inhibition Of Growth ◽  
K 12 ◽  
Chain Lengths ◽  
And Staphylococcus Aureus ◽  
Long Chain

The antimicrobial activities of four long-chain food-grade polyphosphates were studied at concentrations allowed in the food industry (<5,000 ppm) in defined basal media by determining the inhibition of growth of three gram-negative and four gram-positive spoilage and pathogenic bacteria. Both generation time and lag phase of Escherichia coli K-12, E. coli O157: H7, and Salmonella Typhimurium were increased with all of the polyphosphates tested. Bacillus subtilis and Staphylococcus aureus were more sensitive to polyphosphates, but not in all cases, with multiphased growth. The growth of Lactobacillus plantarum was inhibited by polyphosphates at concentrations above 750 ppm, but the lag time of Listeria monocytogenes was shortened by the presence of polyphosphates. No single polyphosphate was maximally inhibitory against all bacteria. Polyphosphates with chain lengths of 12 to 15 were significantly different from those with chain lengths of 18 to 21 depending on the organism and concentrations of polyphosphate used. Overall, higher polyphosphate concentrations resulted in greater inhibition of bacterial growth.

scholarly journals Evaluation of sanitary quality of goat milk in dairy industries from the Cariri region, state of Paraíba

2021 ◽  
Vol 10 (12) ◽  
pp. e596101220735
Author(s):  
Iara Nunes de Siqueira ◽  
Aline Antas Cordeiro Cavalcanti ◽  
Joyce Galvão de Souza ◽  
Filipe Jordão Pereira de Medeiros ◽  
João Carlos Taveira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Pathogenic Bacteria ◽  
Goat Milk ◽  
Salmonella Spp ◽  
Pasteurized Milk ◽  
Enterococcus Spp ◽  
Bacillus Spp ◽  
Thermotolerant Coliforms ◽  
Staphylococcus Spp

The sanitary evaluation of equipment and hands is fundamental to investigate the presence of pathogens in the dairy industry. Then, this study aims to evaluate the sanitization of equipment, workers’ hands, raw and pasteurized milk in goat milk dairies in the Cariri region, state of Paraíba.  Collected 32 samples of four dairies represented by letters A, B, C, and D. The followings contents were analyzed: mesophiles, total and thermotolerant coliforms, Escherichia coli, Staphylococcus aureus, Samonella spp. and Listeria monocytogenes in the reception tank, pasteurization tank, packing machine, package, wall, workers’ hand, and each dairy’s raw and pasteurized milk. After isolation, 84 colonies were confirmed by MALDI TOF. The indicator microorganisms presented variations for the workers’ hands, while A and B stayed within the patterns. For the equipment, only dairy B was within limits. They were out of the standard for mesophiles, total coliforms, and thermotolerant regarding raw and pasteurized milk. The microorganisms, the Enterobacteriaceae family presented a higher frequency, with 77.38%, and within this family, Escherichia coli, Klebsiella spp., and Enterobacter spp. were the most prevalent. Gram-positive corresponded to 22.62%, Bacillus spp., Staphylococcus spp., Enterococcus spp., and Macrococcus caseolyticus. Listeria monocytogenes and Salmonella spp. were not isolated. These demonstrate failures in goat milk processing with pathogenic bacteria in several dairy plants, indicating the need to adjust the product’s quality control.

scholarly journals Prevalence and control of Listeria monocytogenes in the food industry – a review

2016 ◽  
Vol 34 (No. 6) ◽  
pp. 469-487 ◽  
Author(s):  
I. Khan ◽  
J. Khan ◽  
S. Miskeen ◽  
C.N. Tango ◽  
Y.S. Park ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Food Chain ◽  
Food Industry ◽  
Pathogenic Bacteria ◽  
Raw Materials ◽  
Agricultural Practices ◽  
Production Chain ◽  
Hygiene Practices ◽  
Processing Plants ◽  
Serotype 4B

Listeria monocytogenes is a Gram-positive facultative intracellular organism and causative agent of the severe foodborne infection listeriosis. L. monocytogenes is more likely to cause death rather than other pathogenic bacteria that cause foodborne illnesses. It is an ubiquitous organism that can be found in food industry equipment and premises. L. monocytogenes mainly occurs in the food production chain by cross-contamination, making this pathogen a major threat to the food industry. The pathogen may be found at low or moderate levels in the foodstuffs, but the levels involved in listeriosis outbreaks are relatively very high. The majority of isolates from food products belong to serotype 4b and 1/2a. The control of L. monocytogenes can be applied throughout the food chain. Pre- and post-harvest factors such as contact of pigs with pets and pest animals, large group size, hygiene practices, and treatment of manure affected the prevalence of L. monocytogenes in the food chain. Good farm-level practices could be utilised to reduce the occurrence of L. monocytogenes in the farm environment and possibly further in the food chain. Safety and low level of this pathogen in the food chain can be possible with good agricultural practices, good manufacturing practices, and high-quality raw materials. Therefore, food processing plants must be designed carefully with an emphasis on effective cleaning and disinfecting operations in the production line.

Antimicrobial Effects of Silver Nanoparticles against Bacterial Cells Adhered to Stainless Steel Surfaces

2012 ◽  
Vol 75 (4) ◽  
pp. 701-705 ◽  
Author(s):  
EMILIANE A. ARAÚJO ◽  
NÉLIO J. ANDRADE ◽  
LUIS HENRIQUE M. da SILVA ◽  
PATRÍCIA C. BERNARDES ◽  
ÁLVARO V. N. de C. TEIXEIRA ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Stainless Steel ◽  
Food Industry ◽  
Antimicrobial Activities ◽  
New Method ◽  
Resistant Bacteria ◽  
Bacterial Cells ◽  
Antimicrobial Effects ◽  
Log Reduction ◽  
Steel Surfaces

Given the increasing number of antibiotic-resistant bacteria and the need to synthesize new antimicrobials, silver has attracted interest in the scientific community because of its recognized antimicrobial activity. This study aimed to evaluate the antimicrobial effects of silver nanoparticles (NP) obtained by a new method and tested at concentrations of 6 μg/ml and 60 μg/ml against the species Staphylococcus aureus, Listeria innocua, Salmonella Choleraesuis, Pseudomonas aeruginosa, Escherichia coli, and Bacillus cereus. The ability of these nanoparticles to remove or kill vegetative cells adhered to stainless steel surfaces was also evaluated. We observed that the NP obtained with the new method, concentrated silver nanoparticles (CNP), and silver nanoparticles with added sodium chloride (NPNaCl) had high antimicrobial activities (P < 0.05). We also verified that the most effective condition for the removal of P. aeruginosa cells on stainless steel coupons (10 by 10 mm) was immersion of the surfaces in CNP. The CNP treatment produced a 5-log reduction of the microbial population after 30 to 60 min of immersion. The CNP treatment also performed better than water and sodium carbonate, a compound commonly applied in clean-in-place procedures in the food industry, in removing adherent B. cereus cells from stainless steel cylinders. Therefore, these results suggest that NP synthesized by a new procedure may be used as antimicrobials in the food industry, for example, for the sanitization of utensils that come into contact with foods.

scholarly journals Biofilm Formation and the Presence of the Intercellular Adhesion Locus ica among Staphylococci from Food and Food Processing Environments

2003 ◽  
Vol 69 (9) ◽  
pp. 5648-5655 ◽  
Author(s):  
Trond Møretrø ◽  
Lene Hermansen ◽  
Askild L. Holck ◽  
Maan S. Sidhu ◽  
Knut Rudi ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Sodium Chloride ◽  
Northern Blot ◽  
Food Processing ◽  
Biofilm Formation ◽  
Food Industry ◽  
Southern Blotting ◽  
Northern Blot Analysis ◽  
Intercellular Adhesion ◽  
Ammonium Compounds

ABSTRACT In clinical staphylococci, the presence of the ica genes and biofilm formation are considered important for virulence. Biofilm formation may also be of importance for survival and virulence in food-related staphylococci. In the present work, staphylococci from the food industry were found to differ greatly in their abilities to form biofilms on polystyrene. A total of 7 and 21 of 144 food-related strains were found to be strong and weak biofilm formers, respectively. Glucose and sodium chloride stimulated biofilm formation. The biofilm-forming strains belonged to nine different coagulase-negative species of Staphylococcus. The icaA gene of the intercellular adhesion locus was detected by Southern blotting and hybridization in 38 of 67 food-related strains tested. The presence of icaA was positively correlated with strong biofilm formation. The icaA gene was partly sequenced for 22 food-related strains from nine different species of Staphylococcus, and their icaA genes were found to have DNA similarities to previously sequenced icaA genes of 69 to 100%. Northern blot analysis indicated that the expression of the ica genes was higher in strong biofilm formers than that seen with strains not forming biofilms. Biofilm formation on polystyrene was positively correlated with biofilm formation on stainless steel and with resistance to quaternary ammonium compounds, a group of disinfectants.

scholarly journals Assessment of a multiplex detection method for Salmonella enterica, Escherichia coli O157:H7, and Listeria monocytogenes in cow milk

2019 ◽  
Vol 24 (1) ◽  
pp. 277-294
Author(s):  
Rocio Esperanza Patiño-Burbano ◽  
Ana Karina Carrascal ◽  
Jorge Luis Parra-Arango ◽  
José Luis Rodríguez-Bautista
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Detection Rate ◽  
Pathogenic Bacteria ◽  
Simultaneous Detection ◽  
Cow Milk ◽  
Escherichia Coli O157 ◽  
Salmonella Spp ◽  
E Coli ◽  
Microbiological Methods

Raw cow milk is considered one of the most important vehicles for pathogenic bacteria like Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes. These three bacteria are responsible for foodborne diseases. Routine microbiological methods to detect these microorganisms in cow milk can be complicated and time consuming. The aim of this work was to evaluate a method to simultaneously detect Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes in experimentally contaminated cow milk. The assessed method combined a standard microbiological culture step, using a pre-enrichment medium that favors the growth of the three focal microorganisms: SEL broth, followed by a single PCR assay. A total of 43 interference bacterial strains were used to evaluate the method’s specificity. The detection rate for the microbiological method with standard culture media was 10 UFC/mL, and that of the PCR detection, following pre-enrichment in SEL broth, was 10 UFC/mL for S. enterica and L. monocytogenes and between 1 and 5 UFC/mL for E. coli O157:H7. The PCR method showed specificity for the reference strains. Simultaneous detection by multiple PCR using SEL broth was successful for the detection of S. enterica, E. coli O157:H7, and L. monocytogenes in samples of experimentally contaminated cow milk, featuring both a high detection rate and a high specificity. This approach promises to be a feasible routine procedure when testing milk samples in industry and public health control setups.

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