scholarly journals Long filamentous state of Listeria monocytogenes induced by sublethal sodium chloride stress poses risk of rapid increase in colony-forming units

Food Control ◽  
2021 ◽  
pp. 107860
Author(s):  
Shogo Yamaki ◽  
Yuji Kawai ◽  
Koji Yamazaki
Keyword(s):  
Listeria Monocytogenes ◽  
Sodium Chloride ◽  
Colony Forming Units ◽  
Sodium Chloride Stress

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

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.

Modeling the Effects of Temperature, Sodium Chloride, and Green Tea and Their Interactions on the Thermal Inactivation of Listeria monocytogenes in Turkey†

2014 ◽  
Vol 77 (10) ◽  
pp. 1696-1702 ◽  
Author(s):  
VIJAY K. JUNEJA ◽  
JIMENA GARCIA-DÁVILA ◽  
JULIO CESAR LOPEZ-ROMERO ◽  
ETNA AIDA PENA-RAMOS ◽  
JUAN PEDRO CAMOU ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Sodium Chloride ◽  
Protective Effect ◽  
Heat Resistance ◽  
Green Tea ◽  
Thermal Inactivation ◽  
Heating Temperature ◽  
Lethal Effect ◽  
Interactive Effects ◽  
D Values

The interactive effects of heating temperature (55 to 65°C), sodium chloride (NaCl; 0 to 2%), and green tea 60% polyphenol extract (GTPE; 0 to 3%) on the heat resistance of a five-strain mixture of Listeria monocytogenes in ground turkey were determined. Thermal death times were quantified in bags that were submerged in a circulating water bath set at 55, 57, 60, 63, and 65°C. The recovery medium was tryptic soy agar supplemented with 0.6% yeast extract and 1% sodium pyruvate. D-values were analyzed by second-order response surface regression for temperature, NaCl, and GTPE. The data indicated that all three factors interacted to affect the inactivation of the pathogen. The D-values for turkey with no NaCl or GTPE at 55, 57, 60, 63, and 65°C were 36.3, 20.8, 13.2, 4.1, and 2.9 min, respectively. Although NaCl exhibited a concentration-dependent protective effect against heat lethality on L. monocytogenes in turkey, addition of GTPE rendered the pathogen more sensitive to the lethal effect of heat. GTPE levels up to 1.5% interacted with NaCl and reduced the protective effect of NaCl on heat resistance of the pathogen. Food processors can use the predictive model to design an appropriate heat treatment that would inactivate L. monocytogenes in cooked turkey products without adversely affecting the quality of the product.

scholarly journals Antibacterial Efficacy of Synthetic and Natural-Derived Novel Endodontic Irrigant Solutions

2018 ◽  
Vol 29 (5) ◽  
pp. 459-464 ◽  
Author(s):  
Larissa Tais Soligo ◽  
Ediléia Lodi ◽  
Ana Paula Farina ◽  
Matheus Albino Souza ◽  
Cristina de Mattos Pimenta Vidal ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Enterococcus Faecalis ◽  
Grape Seed ◽  
Control Group ◽  
Bacterial Reduction ◽  
Calcium Hypochlorite ◽  
Root Canals ◽  
Colony Forming Units ◽  
Before And After ◽  
Post Hoc

Abstract The aim of this study was to compare the efficacy of grape seed extract (GSE), calcium hypochlorite [Ca(ClO)2], and sodium hypochlorite (NaOCl) irrigant solutions with rotary or reciprocating instrumentation for disinfection of root canals inoculated with Enterococcus faecalis. The mesiobuccal root canals of mandibular molars were prepared and inoculated with Enterococcus faecalis for 21 days. The roots were then randomly divided into the following eight experimental groups (n=11) according to the instrumentation technique and disinfection protocol: ProTaper Next or Reciproc R25 with sodium chloride (control group), 6% NaOCl, 6% Ca(ClO)2, or 50% GSE used for irrigation during instrumentation. The antimicrobial activity was determined on the basis of a reduction in colony-forming units (CFUs) counted on bacterial samples collected before and after root canal instrumentation and expressed as a percentage of reduction. Data were evaluated by two-way ANOVA followed by Tukey HSD post-hoc tests (p<0.05). No significant differences were observed in bacterial reduction between the ProTaper Next and Reciproc R25 systems (p>0.05), regardless of the irrigant solution used. Furthermore, all active solutions (6% NaOCl, 50% GSE, and 6% Ca(ClO)2) showed similar potential to reduce bacterial counts (p>0.05) and were significantly more effective than sodium chloride (control) (p<0.05). The results suggest that the GSE and Ca(ClO)2 have potential clinical application as irrigant solutions in endodontic therapy since they present bactericidal efficacy against Enterococcus faecalis.

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

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.

scholarly journals An overview of Listeria monocytogenes contamination in ready to eat meat, dairy and fishery foods

2017 ◽  
Vol 47 (2) ◽  
Author(s):  
Carla Susana Rodrigues ◽  
Cláudia Valéria Gonçalves Cordeiro de Sá ◽  
Cristiano Barros de Melo
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Sodium Chloride ◽  
Food Safety ◽  
Pregnant Women ◽  
Foodborne Pathogen ◽  
Chloride Content ◽  
The Elderly ◽  
Fishery Products ◽  
Serious Disease

ABSTRACT: Listeria monocytogenes is a relevant foodborne pathogen in public health, responsible for outbreaks of listeriosis often associated to the consumption of ready to eat meat, dairy and fishery products. Listeriosis is a serious disease that can lead to death and mainly affect children, the elderly and immunocompromised individuals. In pregnant women causes abortion or neonatal listeriosis. In Brazil, ready to eat food are appreciated and increasingly consumed by the population. Furthermore, products such as sausages, bologna, hams and cheeses have characteristics such as pH, Aw and sodium chloride content that favor the development of L. monocytogenes during their shelf life. The purpose of this paper was to present an overview of L. monocytogenes contamination in different meat, dairy and fishery products that are ready for consumption and thereby support the adoption of strategies to mitigate this risk, contributing to achieve the appropriate level protection for the consumers and thus strengthen Brazil's food safety system.

Behavior of Listeria monocytogenes at 4 and 22°C in Whey and Skim Milk Containing 6 or 12% Sodium Chloride

1989 ◽  
Vol 52 (9) ◽  
pp. 625-630 ◽  
Author(s):  
DEMETRIOS K. PAPAGEORGIOU ◽  
ELMER H. MARTH
Keyword(s):  
Listeria Monocytogenes ◽  
Sodium Chloride ◽  
Skim Milk ◽  
Salt Tolerant ◽  
Ph Values ◽  
Generation Times ◽  
Order Of Magnitude ◽  
Entire Experiment

Autoclaved samples of skim milk and deproteinated whey were fortified with 6 or 12% NaCl, inoculated with Listeria monocytogenes strains Scott A or California (CA), to contain ca. 1.0 × 103 cfu/ml (in the products with 6% salt) or ca. 5.0 × 103 cfu/ml (in the products with 12% salt) and incubated at 4 and 22°C. The pH values of the 6% salted whey, 6% salted skim milk, 12% salted whey, and 12% salted skim milk were 5.65, 6.20, 5.50, and 6.00 respectively. These values remained relatively constant during the entire experiment. Listeria counts were obtained by surface-plating appropriate dilutions and/or undiluted samples on Trypticase Agar (TA). Samples in which L. monocytogenes was not detected, were re-examined after 2, 4, 6 and 8 weeks of cold-enrichment. Generation times of L. monocytogenes in 6% salted whey at 22°C (3.67 h and 3.56 h for strains Scott A and CA, respectively) were significantly shorter than those in 6% salted skim milk at 22°C (4.31 and 4.42 h for the two strains, respectively). Generation times in 6% salted products at 4°C ranged between 37.49 h and 49.43 h. Maximum populations reached at 22 and 4°C ranged from 7.58 to 8.10 Log10 cfu/ml, and were significantly higher in 6% salted whey than in 6% salted skim milk. In 12% salted whey and skim milk incubated at 22°C, L. monocytogenes gradually decreased in numbers. Strain CA was inactivated within 85 d in 12% salted skim milk or within 110 d in 12% salted whey, and was significantly less salt tolerant than strain Scott A which survived for more than 130 d under the same conditions. Loss of viability by both strains was similar in 12% salted whey and skim milk after 130 d of storage at 4°C, and the decreases in population were less than 0.7 order of magnitude.

Inhibition of Listeria monocytogenes in Cold-process (Smoked) Salmon by Sodium Lactate

1994 ◽  
Vol 57 (2) ◽  
pp. 108-113 ◽  
Author(s):  
GRETCHEN A. PELROY ◽  
MARK E. PETERSON ◽  
PAUL J. HOLLAND ◽  
MEL W. EKLUND
Keyword(s):  
Listeria Monocytogenes ◽  
Sodium Chloride ◽  
Sodium Nitrite ◽  
Sodium Lactate ◽  
The Other ◽  
Water Phase ◽  
Smoked Salmon ◽  
Total Inhibition

Comminuted raw salmon containing various concentrations and combinations of sodium lactate, sodium chloride, and sodium nitrite was inoculated with 10 Listeria monocytogenes cells per g (150 cells/15-g sample), vacuum-packaged in oxygen-impermeable film and stored at 5 or 10°C. Samples were examined for growth of L. monocytogenes and total aerobic microorganisms at specific intervals for up to 50 d. Sodium lactate exhibited a concentration-dependent antilisterial effect that was enhanced by nitrite and/or increased concentrations of NaCl. At 5°C, total inhibition of L monocytogenes was achieved for up to 50 d by 2% sodium lactate in combination with 3% water-phase NaCl. At 10°C, total inhibition was achieved for up to 35 d by 3% sodium lactate in combination with 3% water-phase NaCl, or by 2% sodium lactate in combination with 125 ppm sodium nitrite and 3% water-phase NaCl. Sodium lactate and the other additives also inhibited growth of the aerobic microflora but to a lesser degree than L. monocytogenes.

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