THE EFFECT OF SALTS ON THE GROWTH OF MICROCOCCUS HALODENITRIFICANS N. SP.

1952 ◽  
Vol 30 (2) ◽  
pp. 147-154 ◽  
Author(s):  
J Robinson ◽  
N. E. Gibbons
Keyword(s):  
Sodium Chloride ◽  
Viable Count ◽  
Sodium Bromide ◽  
Lag Phase ◽  
Rate Of Growth

A halophilic coccus, Micrococcus halodenitrificans n. sp., isolated from meat curing brines is described. This organism grows optimally in media containing between 4.4 and 8.8% sodium chloride as determined by viable counts and manometric methods. The viable count decreases in media containing 2.2% or less sodium chloride. As salt concentrations increase above 8.8%, the length of the lag phase increases and the rate of growth decreases. The organism exhibits a specific sodium chloride requirement for growth. However, it continues to respire in the presence of sodium bromide.

scholarly journals Quantitative Interaction Effects of Carbon Dioxide, Sodium Chloride, and Sodium Nitrite on Neurotoxin Gene Expression in Nonproteolytic Clostridium botulinum Type B

2004 ◽  
Vol 70 (5) ◽  
pp. 2928-2934 ◽  
Author(s):  
Maria Lövenklev ◽  
Ingrid Artin ◽  
Oskar Hagberg ◽  
Elisabeth Borch ◽  
Elisabet Holst ◽  
...  
Keyword(s):  
Gene Expression ◽  
Carbon Dioxide ◽  
Growth Rate ◽  
Sodium Chloride ◽  
Optical Density ◽  
Sodium Nitrite ◽  
Clostridium Botulinum ◽  
Lag Phase ◽  
Type B ◽  
Phase Duration

ABSTRACT The effects of carbon dioxide, sodium chloride, and sodium nitrite on type B botulinum neurotoxin (BoNT/B) gene (cntB) expression in nonproteolytic Clostridium botulinum were investigated in a tryptone-peptone-yeast extract (TPY) medium. Various concentrations of these selected food preservatives were studied by using a complete factorial design in order to quantitatively study interaction effects, as well as main effects, on the following responses: lag phase duration (LPD), growth rate, relative cntB expression, and extracellular BoNT/B production. Multiple linear regression was used to set up six statistical models to quantify and predict these responses. All combinations of NaCl and NaNO2 in the growth medium resulted in a prolonged lag phase duration and in a reduction in the specific growth rate. In contrast, the relative BoNT/B gene expression was unchanged, as determined by the cntB-specific quantitative reverse transcription-PCR method. This was confirmed when we measured the extracellular BoNT/B concentration by an enzyme-linked immunosorbent assay. CO2 was found to have a major effect on gene expression when the cntB mRNA levels were monitored in the mid-exponential, late exponential, and late stationary growth phases. The expression of cntB relative to the expression of the 16S rRNA gene was stimulated by an elevated CO2 concentration; the cntB mRNA level was fivefold greater in a 70% CO2 atmosphere than in a 10% CO2 atmosphere. These findings were also confirmed when we analyzed the extracellular BoNT/B concentration; we found that the concentrations were 27 ng · ml−1 · unit of optical density−1 in the 10% CO2 atmosphere and 126 ng · ml−1 · unit of optical density−1 in the 70% CO2 atmosphere.

scholarly journals Food additives reduce lactic acid bacterial growth in culture medium and in meat products, increasing product shelf life

2015 ◽  
Vol 36 (6) ◽  
pp. 3681
Author(s):  
Cleonice Mendes Pereira Sarmento ◽  
Eliane Colla ◽  
Cristiane Canan ◽  
Francieli Dalcanton ◽  
Gláucia Maria Falcão de Aragão
Keyword(s):  
Lactic Acid ◽  
Sodium Chloride ◽  
Shelf Life ◽  
Bacterial Growth ◽  
Culture Medium ◽  
Food Additives ◽  
Meat Products ◽  
Sodium Lactate ◽  
Lag Phase ◽  
Pork Sausages

The uncontrolled growth of lactic acid bacteria (LAB) in meat and meat products leads to product spoilage, and thus shortens product shelf life. Although food additives are known to decrease LAB growth, this effect has not been analyzed in detail. Here, a detailed analysis was performed of the effects of sodium chloride, sodium polyphosphate, sodium lactate, sodium nitrite/nitrate, and garlic on the growth of the Lactobacillus plantarum in culture medium. The results were used to design and test experimental formulations of meat products. Initially, the effect of food additives on L. plantarum was evaluated using a Fractional Factorial Design (FFD), followed by a Central Composite Rotatable Design (CCRD). The Modified Gompertz Model was adjusted to the growth curves to determine the Kinetic parameters of bacterial growth (logarithmic increase in the population, specific growth rate, and lag phase extension). Higher sodium lactate and sodium chloride levels had a negative impact on L. plantarum growth parameters (p?0.05). Therefore, we designed experimental formulations of mortadella and smoked pork sausages containing 4% sodium lactate (w w-1) and 2.4-3.5% sodium chloride (w w-1), and determined LAB growth from samples of stored products produced according to these formulations, in order to determine product shelf life. There was an increased lag phase of LAB growth for most experimental formulations. Also, the experimental smoked pork sausages had a longer shelf life, which was increased by at least 22 days, suggesting that the proposed formulation, with higher than standard lactate concentration, increased the product’s shelf life.

scholarly journals Modeling the Effect of Active Modified Atmosphere Packaging on the Microbial Stability and Shelf Life of Gutted Sea Bass

2019 ◽  
Vol 9 (23) ◽  
pp. 5019 ◽  
Author(s):  
Theofania Tsironi ◽  
Athina Ntzimani ◽  
Eleni Gogou ◽  
Maria Tsevdou ◽  
Ioanna Semenoglou ◽  
...  
Keyword(s):  
Growth Rate ◽  
Shelf Life ◽  
Microbial Growth ◽  
Modified Atmosphere Packaging ◽  
Sea Bass ◽  
Viable Count ◽  
Lag Phase ◽  
Modified Atmosphere ◽  
Total Viable Count ◽  
Microbial Stability

The aim of the study was the evaluation and mathematical modeling of the effect of active modified atmosphere packaging (MAP), by the incorporation of CO2 emitters in the package, on the microbial stability and shelf life of gutted sea bass during refrigerated storage. Gutted sea bass samples were packaged in modified atmosphere (50% CO2–40% N2–10% O2) with and without CO2 emitters (ACT-MAP, MAP) (gas/product volume ratio 3:1) and stored at isothermal conditions: 0 °C, 5 °C, and 10 °C. The gas concentration in the package headspace (%CO2, %O2) and microbial growth (total viable count, TVC, Pseudomonas spp., Enterobacteriaceae spp., lactic acid bacteria) were monitored during storage. The microbial growth was modeled using the Baranyi growth model, and the kinetic parameters (microbial growth rate, lag phase) were estimated at the tested temperature and packaging conditions. The results showed that the ACT-MAP samples presented significantly lower microbial growth compared to the MAP samples. The growth rate of the total viable count at 0 °C was 0.175 and 0.138 d−1 for the MAP and ACT-MAP sea bass, respectively (p < 0.05). The shelf life of the MAP sea bass at 0–10 °C (based on a final TVC value: 7 log CFU g−1) was extended 4–7 days with the addition of a CO2 emitter in the package. The CO2 concentration in the ACT-MAP samples was stabilized at approximately 60%, while the CO2 in the MAP samples was approximately 40% at the end of the shelf life.

Parameters for Control of Listeria monocytogenes in Smoked Fishery Products: Sodium Chloride and Packaging Method

1993 ◽  
Vol 56 (11) ◽  
pp. 938-943 ◽  
Author(s):  
MARK E. PETERSON ◽  
GRETCHEN A. PELROY ◽  
ROHINEE N. PARANJPYE ◽  
FRANK T. POYSKY ◽  
JAMIE S. ALMOND ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Sodium Chloride ◽  
Vacuum Packaging ◽  
Water Phase ◽  
Smoked Fish ◽  
Rate Of Growth ◽  
A Cells ◽  
Smoked Salmon ◽  
Nacl Concentration ◽  
Fishery Products

The behavior of Listeria monocytogenes (10 Scott A cells per g) in cold-process (smoked) salmon containing 3, 5, or 6% water-phase NaCl was evaluated during 30 to 40 d storage at 5 or 10°C in either oxygen-permeable film or vacuum-sealed impermeable film. At 10°C, L. monocytogenes grew to 106 to 108 CFU/g by the second week, with no differences attributed to NaCl concentration except for an initial lag in the 6% NaCl samples. Vacuum packaging suppressed growth of L. monocytogenes by 10- to 100-fold in samples with 3 or 5% NaCl. Inhibition related to NaCl concentration was most apparent at 5°C and L. monocytogenes populations were held below 102 CFU/g by 6% NaCl. Growth of a 327 CFU/g inoculum was about 10-fold greater than a 10 CFU/g inoculum at 10°C and 100-fold greater at 5°C. Growth of two strains isolated from naturally contaminated, commercially prepared, cold-smoked fish did not differ from Scott A. The use of sugar in the product did not influence growth of L. monocytogenes. Maximum populations of aerobic microorganisms reached at 5 and 10°C were similar, although the rate of growth was somewhat delayed at 5°C, and some inhibition was shown by 5 and 6% NaCl and by vacuum packaging.

Gradient-Elastic Tensor in Sodium Chloride and Sodium Bromide

1966 ◽  
Vol 150 (2) ◽  
pp. 546-551 ◽  
Author(s):  
J. L. Marsh ◽  
P. A. Casabella
Keyword(s):  
Sodium Chloride ◽  
Sodium Bromide ◽  
Elastic Tensor

scholarly journals The Response Regulator PhoP of Yersinia pseudotuberculosis Is Important for Replication in Macrophages and for Virulence

2004 ◽  
Vol 72 (9) ◽  
pp. 4973-4984 ◽  
Author(s):  
Jens P. Grabenstein ◽  
Michael Marceau ◽  
Céline Pujol ◽  
Michel Simonet ◽  
James B. Bliska
Keyword(s):  
Cathepsin D ◽  
Wild Type Strain ◽  
Yersinia Pseudotuberculosis ◽  
Response Regulator ◽  
Viable Count ◽  
Infection Model ◽  
Lag Phase ◽  
Intestinal Infection ◽  
Intracellular Growth ◽  
Lag Period

ABSTRACT Yersinia pestis and Yersinia pseudotuberculosis are closely related facultative intracellular pathogens. The response regulator PhoP was previously shown to be important for Y. pestis survival in macrophages and for virulence in a murine bubonic plague infection assay. Here the importance of PhoP for Y. pseudotuberculosis pathogenesis was investigated. Y. pseudotuberculosis phoP mutants were unable to replicate in low-Mg2+ medium or in macrophages. phoP+ Y. pseudotuberculosis strains initiated replication in macrophages after a lag period of ∼5 h, as shown by fluorescence microscopy and viable count assays. Y. pseudotuberculosis phoP mutants died at a low rate in macrophages; there was no decrease in viability over the first 5 h of infection, and there was a 10-fold decrease in viability between 5 and 24 h of infection. Trafficking of phagosomes containing phoP+ or phoP mutant Y. pseudotuberculosis was studied by using immunofluorescence microscopy and cathepsin D as a marker for lysosomes. Phagosomes containing phoP mutant Y. pseudotuberculosis acquired cathepsin D at a higher rate than phagosomes containing phoP+ bacteria. However, the increased rate of marker acquisition for phagosomes containing mutant bacteria was only evident ∼5 h after infection, suggesting that phoP mutants are able to retard phagosome maturation during the lag phase of intracellular growth. The results obtained with a Y. pestis phoP mutant were similar to those described above, except that the rates of intracellular killing and trafficking to cathepsin D-positive vacuoles were significantly higher. A Y. pseudotuberculosis phoP mutant was 100-fold less virulent than the wild-type strain in a murine intestinal infection model, suggesting that survival and replication in macrophages are important for Y. pseudotuberculosis pathogenesis.

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