Pressure Death and Tailing Behavior of Listeria monocytogenes Strains Having Different Barotolerances

2003 ◽  
Vol 66 (11) ◽  
pp. 2057-2061 ◽  
Author(s):  
ABDULLATIF TAY ◽  
THOMAS H. SHELLHAMMER ◽  
AHMED E. YOUSEF ◽  
GRADY W. CHISM
Keyword(s):  
High Pressure ◽  
Listeria Monocytogenes ◽  
High Pressure Processing ◽  
Pressure Treatment ◽  
Probable Number ◽  
Potential Target ◽  
Pressure Sensitive ◽  
Wide Range ◽  
Pressure Resistance ◽  
Kinetics Of

The objectives of this study were to investigate the variability among Listeria monocytogenes strains in response to high-pressure processing, identify the most resistant strain as a potential target of pressure processing, and compare the inactivation kinetics of pressure-resistant and pressure-sensitive strains under a wide range (350 to 800 MPa) of pressure treatments. The pressure resistance of Listeria innocua and nine strains of L. monocytogenes was compared at 400 or 500 MPa and 30°C. Significant variability among strains was observed. The decrease in log CFU/ml during the pressure treatment was from 1.4 to 4.3 at 400 MPa and from 3.9 to >8 at 500 MPa. L. monocytogenes OSY-8578 exhibited the greatest pressure resistance, Scott A showed the greatest pressure sensitivity, and L. innocua had intermediate resistance. On the basis of these findings, L. monocytogenes OSY-8578 is a potential target strain for high-pressure processing efficacy studies. The death kinetics of L. monocytogenes Scott A and OSY-8578 were investigated at 350 and 800 MPa. Survivors at 350 MPa were enumerated by direct plating, and survivors at 800 MPa were enumerated by the most-probable-number technique. Both pressure-resistant and pressure-sensitive strains exhibited non–first-order death behavior, and excessive pressure treatment did not eliminate the tailing phenomenon.

Inactivation of Yersinia pseudotuberculosis 197 and Francisella tularensis LVS in Beverages by High Pressure Processing

2009 ◽  
Vol 72 (1) ◽  
pp. 165-168 ◽  
Author(s):  
JOSEPH E. SCHLESSER ◽  
BRIAN PARISI
Keyword(s):  
High Pressure ◽  
Francisella Tularensis ◽  
Orange Juice ◽  
Yersinia Pseudotuberculosis ◽  
Hold Time ◽  
Skim Milk ◽  
High Pressure Processing ◽  
Pressure Treatment ◽  
Log Reduction ◽  
Pressure Resistance

In 2003, the U.S. Department of Health and Human Services announced a new research program to develop technologies and strategies to prevent and minimize potential food safety and security threats. The threat of terrorist attacks against the nation's food supplies has created the need to study microorganisms not typically associated with foodborne illness. High-pressure processing has been proposed as a treatment to reduce Yersinia pestis and Francisella tularensis LVS levels in beverages. The objectives of this work were to determine the pressure resistance of Y. pseudotuberculosis 197 (surrogate for Y. pestis) and F. tularensis LVS (vaccine strain). For each bacterium, samples of ultrahigh-temperature pasteurized skim milk and pasteurized reduced-acid orange juice (pH ca. 4.2) were inoculated at a minimum level of 5 log CFU/ml. Ten-milliliter samples of the inoculated product were vacuum sealed in polyester pouches and subjected to pressures of 300 and 500 MPa for holding times ranging from 30 s to 6 min. One set of trials was performed at an initial temperature of 10°C and another at 25°C. Processed samples were immediately plated and enumerated. A pressure treatment of 300 MPa at 25°C for less than 6 min was not sufficient to achieve a 5-log reduction of Y. pseudotuberculosis 197 or F. tularensis LVS in milk. However, a pressure treatment of 500 MPa was effective at hold times as low as 30 s. Overall, F. tularensis LVS demonstrated less pressure resistance than Y. pseudotuberculosis 197. Based on these findings, a high-pressure process designed to inactivate 5 log CFU of Y. pseudotuberculosis 197 per ml and F. tularensis LVS in orange juice or milk should be set at or above 500 MPa with a hold time of 2 min or greater.

Effects of High Pressure, Subzero Temperature, and pH on Survival of Listeria monocytogenes in Buffer and Smoked Salmon

2008 ◽  
Vol 71 (8) ◽  
pp. 1612-1618 ◽  
Author(s):  
M. RITZ ◽  
F. JUGIAU ◽  
M. FEDERIGHI ◽  
N. CHAPLEAU ◽  
M. de LAMBALLERIE
Keyword(s):  
High Pressure ◽  
Listeria Monocytogenes ◽  
Differential Resistance ◽  
High Pressure Processing ◽  
Food Preservation ◽  
Subzero Temperature ◽  
Freezing Process ◽  
Pressure Treatment ◽  
Bacterial Cells ◽  
Smoked Salmon

High pressure processing is a novel food preservation technology, applied for over 15 years in the food industry to inactivate spoilage and pathogenic microorganisms. Many studies have shown the differential resistance of bacterial cells to high pressure. Listeria monocytogenes is a bacterium able to grow at refrigerated temperature and to survive for a long time in minimally processed foods such as raw smoked fish. The freezing process does not cause significant decline of L. monocytogenes. The phase diagram of water under pressure permits a pressure treatment under subzero temperature, without the disadvantages of freezing for food quality. The aim of this study was to estimate if combined effects of pressure and subzero temperature could increase the destruction of L. monocytogenes in buffer and in smoked salmon. We investigated effects of high pressure processing (100, 150, and 200 MPa) combined with subzero temperatures (−10, −14, and −18°C) and pH (7.0 and 4.5). Results showed that the most effective high-pressure treatment to inactivate L. monocytogenes was 200 MPa, −18°C, and pH 4.5. The relevance of pressure holding time and the synergistic effect of pressure coupled with the subzero temperature to inactivate bacteria are highlighted. Modifications of physical properties (color and texture) were a lightening of color and an increase of toughness, which might be accepted by consumers, since safety is increased.

Inactivation of Escherichia coli in Broth and Sausage by Combined High Pressure and Lactobacillus casei Cell Extract

2010 ◽  
Vol 16 (5) ◽  
pp. 381-388 ◽  
Author(s):  
Hyun-Jung Chung ◽  
Ahmed E. Yousef
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Lactobacillus Casei ◽  
Treatment Time ◽  
Cell Extract ◽  
High Pressure Processing ◽  
Pressure Treatment ◽  
Scanning Calorimetry ◽  
E Coli ◽  
Pressure Resistance

The purpose of this study was to investigate the effect of combined high pressure and Lactobacillus casei cell extract (CE) on Escherichia coli O157 strains with variation in pressure resistance in broth and sausage. Pressure-resistant (O157:H7 and O157:H12) and -sensitive (O157-M1 and O157-M2) E. coli strains were used. Pressure treatment at 350 MPa for 20 min in broth caused 1.1-1.2 logs reduction in O157:H12 and O157:H7 and 4.1-5.5 logs reduction in the O157-M1 and O157-M2. When high pressure was treated in the presence of CE (32 CEAU/mL), the combination treatment caused a significant inactivation in the pressure-resistant O157:H7 strains resulting in the viability loss of 4.3-4.6 logs and the synergistic effect increased with increase in treatment time (p < 0.05). Similar result was observed in sausage. Differential scanning calorimetry thermogram showed that the presence of Lb. casei CE may cause considerable damage to cellular components of E. coli during the high pressure treatment. The synergy between high pressure processing and Lb. casei OSY-LB6A CE against pressure-resistant E. coli O157 strains suggests the feasibility of using this combination to minimize the risk of transmission of E. coli O157 by food.

Effect of Cheese Water Activity and Carbohydrate Content on the Barotolerance of Listeria monocytogenes Scott A

2006 ◽  
Vol 69 (6) ◽  
pp. 1328-1333 ◽  
Author(s):  
PILAR MORALES ◽  
JAVIER CALZADA ◽  
BUENAVENTURA RODRÍGUEZ ◽  
MÁXIMO de PAZ ◽  
PILAR GAYA ◽  
...  
Keyword(s):  
High Pressure ◽  
Listeria Monocytogenes ◽  
Water Activity ◽  
Dry Matter ◽  
High Pressure Processing ◽  
Carbohydrate Content ◽  
Pressure Treatment ◽  
High Pressure Treatment ◽  
Log Reduction ◽  
Fresh Cheese

High-pressure processing is an appropriate technique for improving the microbiological safety of packaged ready-to-eat foods. The effect of high-pressure treatment on Listeria monocytogenes Scott A inoculated into fresh Hispánico-type cheese and ripe Mahón cheese was investigated. A 3.8-log reduction in the counts of L. monocytogenes Scott A in fresh cheese was recorded after 3 min at 400 MPa and 12°C, whereas 18 min under the same conditions was required to obtain a 1-log reduction in ripe cheese. Dry matter values were 48.96% for fresh cheese and 58.79% for ripe cheese, and water activity (aw) values were 0.983 and 0.922, respectively. In dehydrated fresh cheese (58.20% dry matter) in which 5% NaCl was added to achieve a 0.904 aw value, L. monocytogenes Scott A counts were lowered by only 0.4 log after treatment for 10 min at 400 MPa. On the other hand, in a 60:40 mixture of ripe cheese:distilled water with a 0.976 aw value, the reduction under the same conditions was 3.9 log. Within the aw range of 0.945 to 0.965, L. monocytogenes Scott A barotolerance was significantly higher in fresh cheese than in ripe cheese for equivalent aw values. Carbohydrate content was higher in fresh cheese than in ripe cheese. The addition of lactose at a concentration of 5 mg/g to an 85:15 mixture of ripe cheese:distilled water did not influence L. monocytogenes Scott A barotolerance during treatment for 10 min at 400 MPa. Galactose at a concentration of 5 mg/g had a protective effect during high-pressure treatment, and glucose at a concentration of 5 mg/g favored L. monocytogenes Scott A survival during refrigerated storage of pressurized samples at 8°C for 5 days.

scholarly journals Complete genome of the barotolerant Listeria monocytogenes RO15 strain and comparison with other strains isolated from food and food processing environments

2020 ◽  
Author(s):  
Ilhan Cem Duru ◽  
Margarita Andreevskaya ◽  
Pia Laine ◽  
Tone Mari Rode ◽  
Anne Ylinen ◽  
...  
Keyword(s):  
High Pressure ◽  
Listeria Monocytogenes ◽  
Genome Sequencing ◽  
Viable Cell ◽  
High Pressure Processing ◽  
Genome Comparison ◽  
Cell Counts ◽  
Genome Wide ◽  
Contaminated Food ◽  
Pressure Resistance

Abstract Background Consumption of Listeria monocytogenes contaminated food can cause infection with a high mortality rate in humans and animals. High pressure processing (HPP) is a non-thermal preservation technique adopted by the food industry to inactivate food pathogens, including L. monocytogenes. Strains of L. monocytogenes show different level of resistance to the high pressure. Some strains resist up to 500 MPa pressure. Here, we tested the pressure resistance of 10 different L. monocytogenes strains, including field isolates and widely used type strains, to 400 and 600 MPa pressure treatments. Genome sequencing, and genome comparison of the tested L. monocytogenes strains were performed to investigate the relation between genomic profile and pressure resistance. Results In this study, we showed that none of the tested strains were resistant to 600 MPa, more than 5 log 10 reduction observed for all strains after 1 minute 600 MPa pressure treatment. However, L. monocytogenes strain RO15 showed no significant reduction in viable cell counts after 400 MPa for 1 minute and it was defined as barotolerant. Genome sequencing of so far unsequenced L. monocytogenes strain RO15, 2HF33, MB5, AB199, AB120, C7, and RO4 allowed us to compare their gene content. Genome comparison of 10 tested strains showed that the three most pressure tolerant strains had more than one CRISPR system with self-targeting spacers. Further, several anti-CRISPR genes were detected in these strains. Pan-genome wide analysis showed that 10 prophage genes were significantly associated with the three most barotolerant strains. Conclusions L. monocytogenes strain RO15 was the most pressure tolerant among the selected strains. Genome comparison suggests that there might be a relationship with prophages, CRISPR systems and pressure resistance in L. monocytogenes .

High-Pressure Destruction Kinetics of Listeria monocytogenes on Pork

1999 ◽  
Vol 62 (1) ◽  
pp. 40-45 ◽  
Author(s):  
D. M. MUSSA ◽  
H. S. RAMASWAMY ◽  
J. P. SMITH
Keyword(s):  
High Pressure ◽  
Listeria Monocytogenes ◽  
High Pressure Processing ◽  
Microbial Inactivation ◽  
Hold Period ◽  
Death Time ◽  
Destruction Kinetics ◽  
D Values ◽  
Kinetics Of ◽  
Indigenous Microflora

Packaged fresh pork chops (30-g samples) containing an indigenous bacterial population of ∼107 CFU/g were inoculated with 107 CFU of Listeria monocytogenes Scott A per g, heat sealed, and subjected to high-pressure processing at 200 to 400 MPa for up to 90 min. Total counts and the number of surviving L. monocytogenes cells were determined by a spread plate technique on tryptic soy agar and modified Oxford medium, respectively. The pressure destruction was characterized by a dual-behavior, consisting of a step change in the number of survivors (Pko) with the application of a pressure pulse and a first-order rate drop in the number of survivors during the pressure hold period. Higher pressures resulted in higher rates of microbial inactivation, as indicated by their associated lower D values (and higher k values). The pressure sensitivities of the kinetic parameters were evaluated on the basis of Arrhenius and pressure death time (PDT)-type models. The results suggested that L. monocytogenes was more resistant to pressure inactivation than the indigenous microflora (the volume change of activation, ΔV≠ [Arrhenius model]), and zp values (PDT model) were −4.17 × 10−5 m3 mole−1 and 134 MPa for indigenous microflora and −3.43 × 10−5 m3 mole−1 and 163 MPa for L. monocytogenes respectively.

scholarly journals Unravelling the Molecular Mechanisms Underlying the Protective Effect of Lactate on the High-Pressure Resistance of Listeria monocytogenes

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 677
Author(s):  
Cristina Serra-Castelló ◽  
Ilario Ferrocino ◽  
Anna Jofré ◽  
Luca Cocolin ◽  
Sara Bover-Cid ◽  
...  
Keyword(s):  
High Pressure ◽  
Protective Effect ◽  
Molecular Mechanisms ◽  
Rna Extraction ◽  
Meat Products ◽  
High Pressure Processing ◽  
Membrane Properties ◽  
Short Exposure ◽  
Cooked Ham ◽  
Pressure Resistance

Formulations with lactate as an antimicrobial and high-pressure processing (HPP) as a lethal treatment are combined strategies used to control L. monocytogenes in cooked meat products. Previous studies have shown that when HPP is applied in products with lactate, the inactivation of L. monocytogenes is lower than that without lactate. The purpose of the present work was to identify the molecular mechanisms underlying the piezo-protection effect of lactate. Two L. monocytogenes strains (CTC1034 and EGDe) were independently inoculated in a cooked ham model medium without and with 2.8% potassium lactate. Samples were pressurized at 400 MPa for 10 min at 10 °C. Samples were subjected to RNA extraction, and a shotgun transcriptome sequencing was performed. The short exposure of L. monocytogenes cells to lactate through its inoculation in a cooked ham model with lactate 1h before HPP promoted a shift in the pathogen’s central metabolism, favoring the metabolism of propanediol and ethanolamine together with the synthesis of the B12 cofactor. Moreover, the results suggest an activated methyl cycle that would promote modifications in membrane properties resulting in an enhanced resistance of the pathogen to HPP. This study provides insights on the mechanisms developed by L. monocytogenes in response to lactate and/or HPP and sheds light on the understanding of the piezo-protective effect of lactate.

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