scholarly journals Characterization of Listeria monocytogenes Originating from the Spanish Meat-Processing Chain

Foods ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 542 ◽  
Author(s):  
Rosa Capita ◽  
Amanda Felices-Mercado ◽  
Camino García-Fernández ◽  
Carlos Alonso-Calleja
Keyword(s):  
Listeria Monocytogenes ◽  
Clinical Importance ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Meat Processing ◽  
Hygiene Practices ◽  
Adhesion Ability ◽  
Listeria Ivanovii ◽  
Good Hygiene

Using agglutination techniques, 118 Listeria monocytogenes isolates from red meat and poultry were serotyped. Strains were ascribed to the serotypes 4b/4e (44.1% of the strains), 1/2 (a, b or c; 28.0%), 4c (6.8%), 4d/4e (5.9%) and 3 (a, b or c; 2.5%). Among these are the serotypes most frequently involved in cases of human listeriosis. The susceptibility of 72 strains to 26 antibiotics of clinical importance was determined by disc diffusion (Clinical and Laboratory Standards Institute; CLSI). High levels of resistance were observed to cefoxitin (77.8% of the strains showed resistance), cefotaxime (62.5%), cefepime (73.6%), and nalidixic acid (97.2%), nitrofurantoin (51.4%) and oxacillin (93.1%). Less than 3% of the strains showed resistance to the antibiotic classes used in human listeriosis therapy (i.e., ampicillin, gentamicin, rifampicin, chloramphenicol, enrofloxacin, vancomycin, trimethoprim-sulfamethoxazole, erythromycin, and tetracycline). The influence of species and serotype on the growth kinetics (modified Gompertz equation) and on the adhesion ability (crystal violet staining) of nine isolates of L. monocytogenes (serotypes 1/2a, 1/2b, 1/2c, 3a, 3b, 3c, 4a, 4b, and 4d), and one strain of Listeria ivanovii were investigated. The maximum growth rate (ΔOD420-580/h) varied between 0.073 ± 0.018 (L. monocytogenes 1/2a) and 0.396 ± 0.026 (L. monocytogenes 4b). The isolates of L. monocytogenes belonging to serotypes 3a and 4a, as well as L. ivanovii, showed a greater (p < 0.05) biofilm-forming ability than did the remaining strains, including those that belong to the serotypes commonly implied in human listeriosis (1/2a, 1/2b, 1/2c and 4b). The need for training in good hygiene practices during the handling of meat and poultry is highlighted to reduce the risk of human listeriosis.

Predicting the Growth of Listeria monocytogenes and Salmonella Typhimurium in Diced Celery, Onions, and Tomatoes during Simulated Commercial Transport, Retail Storage, and Display

2019 ◽  
Vol 82 (2) ◽  
pp. 287-300 ◽  
Author(s):  
VICTOR JAYEOLA ◽  
SANGHYUP JEONG ◽  
EVA ALMENAR ◽  
BRADLEY P. MARKS ◽  
KEITH L. VORST ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Modified Atmosphere ◽  
Fluctuating Temperature ◽  
Primary Model ◽  
Microbial Proliferation ◽  
Fresh Cut ◽  
Maximum Population Density

ABSTRACT Temperature is arguably the most important factor affecting microbial proliferation in fresh-cut produce. In this study, growth of Listeria monocytogenes in diced onions and celery and Salmonella Typhimurium in diced tomatoes was determined in modified atmosphere packages and snap-fit containers using three fluctuating temperature scenarios for transport, retail storage, and display. As expected, L. monocytogenes growth in diced onions and celery varied depending on the extent of temperature abuse, with exposure to high and intermediate temperature-abuse scenarios generally being growth supportive. A Baranyi primary model with a square-root secondary model for maximum growth rate, and a linear model for maximum population density, were used to estimate Listeria growth under fluctuating temperature. Accuracy and acceptability of the model prediction were evaluated in terms of root mean square error (RMSE) and acceptable prediction zone (APZ), respectively. Overall, growth predictions for L. monocytogenes were more accurate for celery (RMSE, 0.28 to 0.47) than onions (RMSE, 0.42 to 1.53) under the fluctuating temperature scenarios tested. However, both predictions yielded APZ values that ranged from 82 to 100% for celery and 36 to 78% for onions. In contrast, Salmonella Typhimurium populations increased more than 1 log CFU/g in diced tomatoes under the three fluctuating temperature scenarios studied. Overall, these diced products packaged under a high-oxygen atmosphere showed decreased pathogen growth compared with product stored in a passive modified atmosphere. Findings from this study will be particularly useful in assessing the risk associated with consumption of diced celery, tomatoes, and onions and in designing effective packaging strategies to minimize pathogen growth in fresh-cut produce.

Isolation and Physiological Characterization of Thiothrix sp.

1994 ◽  
Vol 29 (7) ◽  
pp. 261-269 ◽  
Author(s):  
V. Tandoi ◽  
N. Caravaglio ◽  
D. Di Dio Balsamo ◽  
M. Majone ◽  
M. C. Tomei
Keyword(s):  
Growth Yield ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Yield Coefficient ◽  
Simultaneous Presence ◽  
Mixotrophic Growth ◽  
Physiological Characterization ◽  
South Italy ◽  
Mixotrophic Conditions

Thiothrix CT3 was isolated in pure culture by micromanipulation technique. The growth of this microorganism was analyzed in autotrophic, heterotrophic and mixotrophic conditions, in a bicarbonate-containing mineral medium supplemented with thiosulphate and/or acetate. Thiothrix CT3 was able to grow in all the conditions examined: the maximum growth rates estimated were 1.8, 2.5 and 2.5 d−1 respectively. The capacity of this organism to grow autotrophically, as supposed by Winogradsky in 1888, is a strong advantage over the other bacteria present in activated sludge, when sulphides are produced or carried by the sewer. Both the maximum growth rate and growth yield coefficient shown during heterotrophic and mixotrophic growth were comparable, indicating that the simultaneous presence of two substrates (acetate and a reduced sulphur compound) does not give it any particular advantage. The strong presence of Thiothrix spp. in many plants located in South Italy can be explained by the wide nutritional versatility of this filamentous bacterium.

scholarly journals Genomic Characterization of Listeria monocytogenes Isolated From Ready-to-Eat Meat and Meat Processing Environments in Poland

2020 ◽  
Vol 11 ◽  
Author(s):  
Monika Kurpas ◽  
Jacek Osek ◽  
Alexandra Moura ◽  
Alexandre Leclercq ◽  
Marc Lecuit ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Meat Processing ◽  
Genomic Characterization

Prediction of Persistence of Listeria monocytogenes ST451 in a Rabbit Meat Processing Plant in the Czech Republic

2019 ◽  
Vol 82 (8) ◽  
pp. 1350-1356
Author(s):  
TEREZA GELBÍČOVÁ ◽  
MARTINA FLORIANOVÁ ◽  
ZUZANA TOMÁŠTÍKOVÁ ◽  
LUCIE POSPÍŠILOVÁ ◽  
IVANA KOLÁČKOVÁ ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Core Genome ◽  
Sequence Type ◽  
Processing Plant ◽  
Meat Processing ◽  
Sequencing Method ◽  
Serotype 1 ◽  
Rabbit Meat ◽  
Meat Samples

ABSTRACT This study was focused on characterization of the genetic diversity of Listeria monocytogenes isolated from packed fresh rabbit meat obtained from one producer via retail outlets. The partial aim was to compare the characteristics of a suspect persistent strain with strains from human cases. The occurrence of L. monocytogenes in vacuum-packed rabbit meat was monitored during 2013 to 2016. All strains were characterized by serotyping, pulsed-field gel electrophoresis, and multilocus sequence typing (MLST). Selected strains, which represented each year, were analyzed using the whole genome sequencing method. L. monocytogenes was detected in 21 (38%) of 56 originally packed rabbit meat samples from one food producer during the whole monitored period. All strains showed the identical serotype (1/2a), AscI/ApaI pulsotype (735/2), and sequence type (ST451). The clonal similarity of strains from rabbit meat was also confirmed on the basis of core genome MLST (on 1,701 loci). This fact suggests the occurrence of a suspect persistent strain in the meat processing plant. Results of core genome MLST enabled us to unambiguously exclude rabbit meat as a source of listeriosis in humans caused by the indistinguishable AscI/ApaI pulsotype and sequence type, although all strains carried all genes important for the virulence of L. monocytogenes. No specific genes that may be associated with its persistence in the food processing environment were detected among the tested strains of ST451. HIGHLIGHTS

scholarly journals PCR-based methodologies for detection and characterization of Listeria monocytogenes and Listeria ivanovii in foods and environmental sources

2017 ◽  
Vol 6 (2) ◽  
pp. 39-59 ◽  
Author(s):  
Jin-Qiang Chen ◽  
Stephanie Healey ◽  
Patrick Regan ◽  
Pongpan Laksanalamai ◽  
Zonglin Hu
Keyword(s):  
Listeria Monocytogenes ◽  
Listeria Ivanovii

Predicting the growth of Listeria monocytogenes in cooked sliced deli turkey breast as function of clean label antimicrobial, pH, moisture and salt

2021 ◽  
Author(s):  
SUBASH SHRESTHA ◽  
Jerry Joseph Erdmann ◽  
Sean A Smith
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Control Measure ◽  
Salt Content ◽  
Maximum Growth ◽  
Lag Time ◽  
Maximum Growth Rate ◽  
Lag Phase ◽  
Design Matrix ◽  
Least Squares Regression

The use of antimicrobials in formulations of ready-to-eat meat and poultry products has been identified as a major strategy to control Listeria monocytogenes . The USDA-FSIS recommends no more than 2-logs of Listeria outgrowth over the stated shelf life if antimicrobials are used as a control measure for a product with post-lethality environmental exposure. This study was designed to understand the efficacy of a clean label antimicrobial against the growth of L. monocytogenes as affected by the product attributes. A response surface method-central composite design was used to investigate the effects of product pH, moisture, salt content, and a commercial “clean-label” antimicrobial on the growth of L. monocytogenes in a model turkey deli meat formulation. Thirty treatment combinations of pH (6.3, 6.5, and 6.7), moisture (72, 75, and 78%), salt (1.0, 1.5, and 2.0%), and antimicrobial (0.75, 1.375, and 2.0%) with six replicated center points and eight design star points were evaluated. Treatments were surface inoculated with a 3 log 10 CFU/g target of a five-strain L. monocytogenes cocktail, vacuum packaged, and stored at 5°C for up to 16 weeks. Populations of L. monocytogenes were enumerated from triplicate samples every week until the stationary growth phase was reached. The enumeration data was fitted to a Baranyi and Roberts growth curve to calculate the lag time and maximum growth rate for each treatment.  Linear least-squares regression of the lag-time and growth-rate against the full quadratic, including the second order interaction terms, design matrix was performed. Both lag time and maximum growth rate were significantly affected ( p &lt;0.01) by the antimicrobial concentration and product pH. Product moisture and salt content affected ( p &lt;0.05) lag phase and maximum growth rate, respectively. The availability of a validated growth model assists meat scientists and processors with faster product development and commercialization.

CHARACTERIZATION Of Bi-BASED WHISKERS BY THE METHOD OF Al2O3-SEEDED GLASSY QUENCHED PLATELETS

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4497-4501 ◽  
Author(s):  
S. KISHIDA ◽  
H. UEMOTO
Keyword(s):  
Full Width Half Maximum ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Previous Method ◽  
Full Width ◽  
Temperature Transition ◽  
High Quality ◽  
Maximum Value ◽  
Good Crystallinity

We prepared the Bi 2 Sr 2 Ca n-1 Cu n O y (Bi-based) whiskers by the method of Al 2 O 3-seeded by the method was about 3 times larger than that by the previous method glassy quenched platelets (ASGQP). The maximum growth rate of the whiskers obtained without any Al 2 O 3 seeding. From the resistance-temperature (R-T) characteristics, we found that the temperature transition widths of the Bi-2212 and the Bi-2223 phases were about 2K and 4K, respectively. In addition, the whiskers showed that the FWHM (full-width-half-maximum) value of the (0010) XRD peak was less than 0.06°. The critical current density of the whiskers was more than 104 A/cm 2 at 60K and 0T. The results indicate that the whiskers grown by the ASGQP method have good crystallinity and high quality.

PHYSIOLOGICAL CHARACTERIZATION OF ADAPTIVE CLONES IN EVOLVING POPULATIONS OF THE YEAST, SACCHAROMYCES CEREVISIAE

Genetics ◽  
1985 ◽  
Vol 110 (2) ◽  
pp. 173-185
Author(s):  
Julian Adams ◽  
Charlotte Paquin ◽  
Paul W Oeller ◽  
Lester W Lee
Keyword(s):  
Glucose Uptake ◽  
Continuous Culture ◽  
Growth Parameters ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Yeast Saccharomyces Cerevisiae ◽  
Adaptive Mutations ◽  
Physiological Characterization ◽  
Evolving Populations

ABSTRACT Populations of a diploid strain of S. cerevisiae were grown in glucose-limited continuous culture for more than 260 generations. A series of seven sequential adaptive changes were identified by monitoring the frequency of cycloheximide resistance in these populations. Samples were taken from the continuous cultures following each adaptive shift and characterized physiologically to determine (1) the range of phenotypes that can be selected in a precisely defined constant environment and (2) the order and predictability of the occurrence of the adaptive mutations in evolving populations. The clones were characterized with respect to the growth parameters, maximum growth rate, saturation coefficient and yield, as well as for changes in cell size and geometry and rate of glucose uptake. The maximum growth rates of the seven adaptive clones were very similar, but in contrast the saturation coefficients differed substantially. Surprisingly, not all clones showed reductions in the saturation coefficients, in comparison to the immediately preceding clones, as would be predicted from classical continuous culture kinetics. In addition, yield estimates first increased and then decreased for later isolated adaptive clones. In general, the results suggest epistatic interactions between the adaptive clones, consistent with earlier published results. The rate of glucose uptake, as measured by 14Cxylose uptake, increased dramatically after the selection and fixation of seven adaptive clones. Progressive decreases in cell volume and changes in cell geometry, resulting in increased surface area to volume ratios, were also observed in the adaptive clones, but these changes were not always seen in other haploid and diploid yeast populations evolving under the same conditions. Such changes may be easily explainable in terms of the characteristics of the glucose-limited environment. The significance of the results to the evolution of microorganisms under nutrient-limiting conditions is discussed.

scholarly journals Production, purification and characterization of hemolysins from Listeria ivanovii and Listeria monocytogenes Sv4b

1989 ◽  
Vol 57 (2) ◽  
pp. 197-202 ◽  
Author(s):  
Jürgen Kreft ◽  
Dorothee Funke ◽  
Albert Haas ◽  
Friedrich Lottspeich ◽  
Werner Goebel
Keyword(s):  
Listeria Monocytogenes ◽  
Purification And Characterization ◽  
Listeria Ivanovii

Assays for Phospholipid-Dependent Formation of Thrombin and Xa: A Potential Method for Quantifying Lupus Anticoagulant Activity

1991 ◽  
Vol 66 (04) ◽  
pp. 453-458 ◽  
Author(s):  
John T Brandt
Keyword(s):  
Specific Activity ◽  
Anticoagulant Activity ◽  
Factor Xa ◽  
Clinical Importance ◽  
Potential Method ◽  
Quantitative Expression ◽  
Increased Risk ◽  
Apparent Association

SummaryLupus anticoagulants (LAs) are antibodies which interfere with phospholipid-dependent procoagulant reactions. Their clinical importance is due to their apparent association with an increased risk of thrombo-embolic disease. To date there have been few assays for quantifying the specific activity of these antibodies in vitro and this has hampered attempts to purify and characterize these antibodies. Methods for determining phospholipid-dependent generation of thrombin and factor Xa are described. Isolated IgG fractions from 7 of 9 patients with LAs were found to reproducibly inhibit enzyme generation in these assay systems, permitting quantitative expression of inhibitor activity. Different patterns of inhibitory activity, based on the relative inhibition of thrombin and factor Xa generation, were found, further substantiating the known heterogeneity of these antibodies. These systems may prove helpful in further purification and characterization of LAs.

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