Influence of habituation to inorganic and organic acid conditions on the cytoplasmic membrane composition of Listeria monocytogenes

AbstractListeria monocytogenes is a food-borne pathogen with the ability to grow at low temperatures down to − 0.4 °C. Maintaining cytoplasmic membrane fluidity by changing the lipid membrane composition is important during growth at low temperatures. In Listeria monocytogenes, the dominant adaptation effect is the fluidization of the membrane by shortening of fatty acid chain length. In some strains, however, an additional response is the increase in menaquinone content during growth at low temperatures. The increase of this neutral lipid leads to fluidization of the membrane and thus represents a mechanism that is complementary to the fatty acid-mediated modification of membrane fluidity. This study demonstrated that the reduction of menaquinone content for Listeria monocytogenes strains resulted in significantly lower resistance to temperature stress and lower growth rates compared to unaffected control cultures after growth at 6 °C. Menaquinone content was reduced by supplementation with aromatic amino acids, which led to a feedback inhibition of the menaquinone synthesis. Menaquinone-reduced Listeria monocytogenes strains showed reduced bacterial cell fitness. This confirmed the adaptive function of menaquinones for growth at low temperatures of this pathogen.

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Effect of Potassium Lactate and a Potassium Lactate–Sodium Diacetate Blend on Listeria monocytogenes Growth in Modified Atmosphere Packaged Sliced Ham

Journal of Food Protection ◽

10.4315/0362-028x-70.10.2297 ◽

2007 ◽

Vol 70 (10) ◽

pp. 2297-2305 ◽

Cited By ~ 22

Author(s):

L. A. MELLEFONT ◽

T. ROSS

Keyword(s):

Listeria Monocytogenes ◽

Organic Acid ◽

Shelf Life ◽

Storage Temperature ◽

Modified Atmosphere ◽

Acid Salt ◽

Potassium Lactate ◽

Sodium Diacetate ◽

Potential Inhibitors ◽

And Storage

Two commercially available organic acid salts, potassium lactate (PURASAL HiPure P) and a potassium lactate–sodium diacetate blend (PURASAL Opti.Form PD 4), were assessed as potential inhibitors of Listeria monocytogenes growth in modified atmosphere packaged (MAP) sliced ham in challenge studies. The influence of the initial inoculation level of L. monocytogenes (101 or 103 CFU g−1) and storage temperature (4 or 8°C) was also examined. The addition of either organic acid salt to MAP sliced ham strongly inhibited the growth of L. monocytogenes during the normal shelf life of the product under ideal refrigeration conditions (4°C) and even under abusive temperature conditions (i.e., 8°C). During the challenge studies and in the absence of either organic acid salt, L. monocytogenes numbers increased by 1,000-fold after 20 days at 8°C and 10-fold after 42 days at 4°C. Both organic acid salt treatments were found to be listeriostatic rather than listericidal. The addition of either organic acid salt to the MAP ham also reduced the growth of indigenous microflora, i.e., aerobic microflora and lactic acid bacteria. The influence of these compounds on the risk of listeriosis in relation to product shelf life is discussed.

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Control of Listeria monocytogenes on Frankfurters with Antimicrobials in the Formulation and by Dipping in Organic Acid Solutions

Journal of Food Protection ◽

10.4315/0362-028x-67.11.2456 ◽

2004 ◽

Vol 67 (11) ◽

pp. 2456-2464 ◽

Cited By ~ 66

Author(s):

I. M. BARMPALIA ◽

I. GEORNARAS ◽

K. E. BELK ◽

J. A. SCANGA ◽

P. A. KENDALL ◽

...

Keyword(s):

Acetic Acid ◽

Lactic Acid ◽

Listeria Monocytogenes ◽

Organic Acid ◽

The United States ◽

Acid Solutions ◽

Overall Acceptability ◽

Bactericidal Effects ◽

Yeasts And Molds ◽

And Storage

The antilisterial activity of sodium lactate (SL) and sodium diacetate (SD) was evaluated in a frankfurter formulation and in combination with a dipping treatment into solutions of lactic acid or acetic acid after processing and inoculation. Pork frankfurters were formulated with 1.8% SL or 0.25% SD or combinations of 1.8% SL with 0.25 or 0.125% SD. After processing, frankfurters were inoculated (2 to 3 log CFU/cm2) with a 10-strain composite of Listeria monocytogenes and left undipped or were dipped (2 min) in 2.5% solutions of lactic acid or acetic acid (23 ± 2°C) before vacuum packaging and storage at 10°C for 40 days. Total microbial populations and L. monocytogenes, lactic acid bacteria, and yeasts and molds were enumerated during storage. Sensory evaluations also were carried out on frankfurters treated and/or formulated with effective antimicrobials. The combination of 1.8% SL with 0.25% SD provided complete inhibition of L. monocytogenes growth throughout storage. Dipping in lactic acid or acetic acid reduced initial populations by 0.7 to 2.1 log CFU/cm2, but log CFU/cm2. For samples containing single antimicrobials and dipped in lactic acid or acetic acid, L. monocytogenes growth was completely inhibited or reduced over 12 and 28 days, respectively, whereas final populations were lower (P < 0.05) than those in undipped samples of the same formulations. Bactericidal effects during storage (reductions of 0.6 to 1.0 log CFU/cm2 over 28 to 40 days) were observed in frankfurters containing combinations of SL and SD that were dipped in organic acid solutions. Inclusion of antimicrobials in the formulation and/or dipping the product into organic acid solutions did not affect (P > 0.05) the flavor and overall acceptability of products compared with controls. The results of this study may be valuable to meat processors as they seek approaches for meeting new regulatory requirements in the United States.

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Comparison of Inorganic and Organic Acid Etching Processes on Germanium(100)

ECS Transactions ◽

10.1149/09202.0057ecst ◽

2019 ◽

Vol 92 (2) ◽

pp. 57-63

Author(s):

Stacy Lynn Heslop ◽

Anthony J. Muscat

Keyword(s):

Organic Acid ◽

Acid Etching ◽

Inorganic And Organic

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Membrane Fluidity Adjustments in Ethanol-Stressed Oenococcus oeni Cells

Applied and Environmental Microbiology ◽

10.1128/aem.69.10.5826-5832.2003 ◽

2003 ◽

Vol 69 (10) ◽

pp. 5826-5832 ◽

Cited By ~ 86

Author(s):

M. Graça Da Silveira ◽

Elena A. Golovina ◽

Folkert A. Hoekstra ◽

Frank M. Rombouts ◽

Tjakko Abee

Keyword(s):

Membrane Fluidity ◽

Cytoplasmic Membrane ◽

De Novo ◽

Oenococcus Oeni ◽

Resonance Spectroscopy ◽

Water Interface ◽

Membrane Composition ◽

Intact Cells ◽

Short Term Adaptation ◽

Tolerance To Ethanol

ABSTRACT The effect of ethanol on the cytoplasmic membrane of Oenococcus oeni cells and the role of membrane changes in the acquired tolerance to ethanol were investigated. Membrane tolerance to ethanol was defined as the resistance to ethanol-induced leakage of preloaded carboxyfluorescein (cF) from cells. To probe the fluidity of the cytoplasmic membrane, intact cells were labeled with doxyl-stearic acids and analyzed by electron spin resonance spectroscopy. Although the effect of ethanol was noticeable across the width of the membrane, we focused on fluidity changes at the lipid-water interface. Fluidity increased with increasing concentrations of ethanol. Cells responded to growth in the presence of 8% (vol/vol) ethanol by decreasing fluidity. Upon exposure to a range of ethanol concentrations, these adapted cells had reduced fluidity and cF leakage compared with cells grown in the absence of ethanol. Analysis of the membrane composition revealed an increase in the degree of fatty acid unsaturation and a decrease in the total amount of lipids in the cells grown in the presence of 8% (vol/vol) ethanol. Preexposure for 2 h to 12% (vol/vol) ethanol also reduced membrane fluidity and cF leakage. This short-term adaptation was not prevented in the presence of chloramphenicol, suggesting that de novo protein synthesis was not involved. We found a strong correlation between fluidity and cF leakage for all treatments and alcohol concentrations tested. We propose that the protective effect of growth in the presence of ethanol is, to a large extent, based on modification of the physicochemical state of the membrane, i.e., cells adjust their membrane permeability by decreasing fluidity at the lipid-water interface.

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Behaviour of inorganic and organic acid anhydrides in disulphuric acid

Journal of the Chemical Society A Inorganic Physical Theoretical ◽

10.1039/j19710002127 ◽

1971 ◽

pp. 2127 ◽

Cited By ~ 6

Author(s):

Ram Chand Paul ◽

V. P. Kapila ◽

J. K. Puri ◽

K. C. Malhotra

Keyword(s):

Organic Acid ◽

Acid Anhydrides ◽

Inorganic And Organic

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Identification of Plasmalogens in the Cytoplasmic Membrane of Bifidobacterium animalis subsp. lactis

Applied and Environmental Microbiology ◽

10.1128/aem.06968-11 ◽

2011 ◽

Vol 78 (3) ◽

pp. 880-884 ◽

Cited By ~ 15

Author(s):

Taylor S. Oberg ◽

Robert E. Ward ◽

James L. Steele ◽

Jeff R. Broadbent

Keyword(s):

Oxidative Stress ◽

Environmental Stress ◽

Stress Resistance ◽

Cell Membranes ◽

Cytoplasmic Membrane ◽

Eukaryotic Cell ◽

Bacterial Membrane ◽

Membrane Composition ◽

Content Type ◽

Bifidobacterium Animalis

ABSTRACTPlasmalogens are ether-linked lipids that may influence oxidative stress resistance of eukaryotic cell membranes. Since bacterial membrane composition can influence environmental stress resistance, we explored the prevalence of plasmalogens in the cytoplasmic membrane ofBifidobacterium animalissubsp.lactis. Results showed plasmalogens are a major component of theB. animalissubsp.lactismembrane.

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