scholarly journals Study of the population dynamics of Listeria monocytogenes and Pseudomonas fluorescens in buffalo-milk mozzarella cheese by means of challenge testing

2016 ◽  
Vol 5 (3) ◽  
Author(s):  
Donatella Nava ◽  
Salvatore Capo ◽  
Vincenzo Caligiuri ◽  
Valerio Giaccone ◽  
Loredana Biondi ◽  
...  
Keyword(s):  
At Risk ◽  
Population Dynamics ◽  
Listeria Monocytogenes ◽  
Pseudomonas Fluorescens ◽  
Bacterial Load ◽  
Challenge Test ◽  
Buffalo Milk ◽  
Mozzarella Cheese ◽  
Challenge Testing

Campania buffalo mozzarella is a greatly appreciated cheese in Italy and worldwide. From a microbiological standpoint, it is a highly perishable food and potentially at risk of contamination by pathogens such as <em>Listeria monocytogenes</em> (<em>L. monocytogenes</em>). The present paper reports the results of a challenge test carried out with the aim to assess the population dynamics of <em>L. monocytogenes</em>, alone and in the presence of <em>Pseudomonas fluorescens</em> (<em>Ps. fluorescens</em>), in buffalo mozzarella. For this purpose buffalo mozzarella samples were contaminated with <em>L. monocytogenes</em> alone or combined with <em>Ps. fluorescens</em>. In samples wherein <em>L. monocytogenes</em> was inoculated alone, the bacterial load remained unchanged. By contrast, in samples contaminated with <em>L. monocytogenes</em> and <em>Ps. fluorescens</em>, the growth of <em>L. monocytogenes</em> was increased.

Growth of Listeria monocytogenes in the Presence of Pseudomonas fluorescens at 7 or 13°C in Skim Milk

1989 ◽  
Vol 52 (12) ◽  
pp. 852-855 ◽  
Author(s):  
SEHAM A. FARRAG ◽  
ELMER H. MARTH
Keyword(s):  
Listeria Monocytogenes ◽  
Pseudomonas Fluorescens ◽  
Incubation Period ◽  
Skim Milk

Autoclaved samples of skim milk were inoculated with Listeria monocytogenes (strain Scott A, California or V7), Pseudomonas fluorescens (strain P26 or B52), or a combination of L. monocytogenes plus P. fluorescens, and incubated at 7 or 13°C for 8 weeks. McBride Listeria Agar was used to determine populations of L. monocytogenes (at 0, 7, 14, 28, 42, or 56 d), and Pseudomonas isolation agar to enumerate P. fluorescens. Growth of L. monocytogenes was somewhat enhanced after 7 d of incubation at 7 but not at 13°C in the presence of pseudomonads. However, after 14 d and until the end of the incubation period (56 d), slight inactivation of L. monocytogenes in the presence of P. fluorescens was observed. L. monocytogenes did not affect growth or survival of P. fluorescens; also, no marked changes in pH of the milk were caused either by L. monocytogenes alone or by L. monocytogenes plus P. fluorescens.

scholarly journals Droplet Digital PCR (ddPCR) Analysis for the Detection and Quantification of Cow DNA in Buffalo Mozzarella Cheese

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1270
Author(s):  
Anna Cutarelli ◽  
Andrea Fulgione ◽  
Pasquale Fraulo ◽  
Francesco Paolo Serpe ◽  
Pasquale Gallo ◽  
...  
Keyword(s):  
Digital Pcr ◽  
Buffalo Milk ◽  
Cow Milk ◽  
Mozzarella Cheese ◽  
Chain Reaction ◽  
New Methods ◽  
Protected Designation Of Origin ◽  
Commission Regulation ◽  
Polymerase Chain ◽  
Digital Polymerase Chain Reaction

Buffalo mozzarella cheese is one of the most appreciated traditional Italian products and it is certified as a Protected Designation of Origin (PDO) product under the European Commission Regulation No. 1151/2012. It is obtained exclusively from buffalo milk. If made from cow milk, or a mixture of buffalo and cow milk, buffalo mozzarella cheese does not qualify as a PDO product. In order to maximize their profits, some producers market buffalo mozzarella that also contains cow milk as a PDO product, thus defrauding consumers. New methods for revealing this fraud are therefore needed. One such method is the droplet digital Polymerase Chain Reaction (ddPCR). Thanks to its high precision and sensitivity, the ddPCR could prove an efficacious means for detecting the presence of cow milk in buffalo mozzarella cheese that is marketed as a PDO product. ddPCR has proved able to detect the DNA of cow and/or buffalo milk in 33 buffalo mozzarella cheeses labelled as PDO products, and experimental evidence could support its application in routine analyses.

scholarly journals Expression of NADPH Oxidase-Dependent Resistance to Listeriosis in Mice Occurs during the First 6 to 12 Hours of Liver Infection

2002 ◽  
Vol 70 (12) ◽  
pp. 7179-7181 ◽  
Author(s):  
Ronald LaCourse ◽  
Lynn Ryan ◽  
Robert J. North
Keyword(s):  
Listeria Monocytogenes ◽  
Nadph Oxidase ◽  
Bacterial Load ◽  
Wild Type ◽  
Liver Infection

ABSTRACT Wild-type mice inoculated with Listeria monocytogenes intravenously were capable of reducing the bacterial load in their livers by 90% within 6 h. In contrast, mice with deletions of the gene for NADPH oxidase were incapable of expressing this early oxygen-dependent anti-Listeria defense and consequently showed higher levels of liver infection at later times.

scholarly journals Thermal inactivation and growth potential of Listeria monocytogenes in smoked tench

2016 ◽  
Vol 5 (3) ◽  
Author(s):  
Raffaella Branciari ◽  
Andrea Valiani ◽  
Raffaella Franceschini ◽  
David Ranucci ◽  
Alessia Lupattelli ◽  
...  
Keyword(s):  
Experimental Study ◽  
Listeria Monocytogenes ◽  
Thermal Inactivation ◽  
Challenge Test ◽  
Listeria Innocua ◽  
Growth Potential ◽  
Post Processing ◽  
Colony Forming Unit ◽  
Post Process ◽  
Hygiene Measures

An experimental study for the evaluation of <em>Listeria monocytogenes</em> inactivation during a hot smoking process in tench was performed using <em>Listeria innocua</em> strains. Furthermore, the survival of <em>L. monocytogenes</em> in smoked tench was determined after post-processing in contaminated samples, evaluating the growth potential during storage. <em>L. innocua</em> was not detected after the smoking process. In the challenge test, the growth potential of <em>L. monocytogenes</em> was 5.68 log colony forming unit g<sup>−1</sup>. The results showed that hot smoking at an inner temperature around 72°C is able to eliminate the microorganism. Nevertheless, the product is able to support the growth of the pathogen if post-process contamination occurs, as the food is suitable for <em>Listeria</em> multiplication. Product recontamination should be prevented by means of appropriate application of hygiene measures.

scholarly journals ERS technical standard on bronchial challenge testing: pathophysiology and methodology of indirect airway challenge testing

2018 ◽  
Vol 52 (5) ◽  
pp. 1801033 ◽  
Author(s):  
Teal S. Hallstrand ◽  
Joerg D. Leuppi ◽  
Guy Joos ◽  
Graham L. Hall ◽  
Kai-Håkon Carlsen ◽  
...  
Keyword(s):  
Airway Hyperresponsiveness ◽  
Task Force ◽  
Challenge Test ◽  
Technical Standard ◽  
Bronchial Challenge ◽  
Airway Narrowing ◽  
Airway Function ◽  
Challenge Testing ◽  
Challenge Tests ◽  
Indirect Tests

Recently, this international task force reported the general considerations for bronchial challenge testing and the performance of the methacholine challenge test, a “direct” airway challenge test. Here, the task force provides an updated description of the pathophysiology and the methods to conduct indirect challenge tests. Because indirect challenge tests trigger airway narrowing through the activation of endogenous pathways that are involved in asthma, indirect challenge tests tend to be specific for asthma and reveal much about the biology of asthma, but may be less sensitive than direct tests for the detection of airway hyperresponsiveness. We provide recommendations for the conduct and interpretation of hyperpnoea challenge tests such as dry air exercise challenge and eucapnic voluntary hyperpnoea that provide a single strong stimulus for airway narrowing. This technical standard expands the recommendations to additional indirect tests such as hypertonic saline, mannitol and adenosine challenge that are incremental tests, but still retain characteristics of other indirect challenges. Assessment of airway hyperresponsiveness, with direct and indirect tests, are valuable tools to understand and to monitor airway function and to characterise the underlying asthma phenotype to guide therapy. The tests should be interpreted within the context of the clinical features of asthma.

scholarly journals Growth kinetics of Salmonella Typhimurium and Listeria monocytogenes in buffalo milk under different processing and storage conditions

2021 ◽  
Vol 51 (11) ◽  
Author(s):  
Joelson Sousa Lima ◽  
Ana Paula Presley Oliveira Sampaio ◽  
Mylla Christy da Silva Dufossé ◽  
Paula Fernanda Morais de Sousa ◽  
Josyane Brasil da Silva ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Growth Kinetics ◽  
Storage Conditions ◽  
Buffalo Milk ◽  
Production Chain ◽  
Pasteurized Milk ◽  
Processing And Storage ◽  
And Storage ◽  
Kinetics Of

ABSTRACT: Buffalo milk is rich in nutrients and can serve as a substrate for the proliferation of microorganisms. Thus, the objective of the present study was to evaluate the growth kinetics of Salmonella Typhimurium and Listeria monocytogenes in buffalo milk under different processing and storage conditions. Samples of raw and pasteurized milk were inoculated with 1 CFU of each bacterium, separately and together, per 25 mL. After contamination, samples were stored at 8 °C or 37 °C, and bacterial counts were performed at 24, 48, and 168 h. In addition, the accompanying microbiota growth, pH, and the effect of these variables on the growth kinetics of microorganisms were monitored. The pathogens tested were able to proliferate under most conditions tested, reaching high titers throughout the experimental period. At 37 °C, there was a decrease in pH and an increase in the accompanying microbiota that interfered with the microbial growth curve. It was also observed that pasteurized milk subjected to 8 °C provided better conditions for the multiplication of bacteria. Therefore, it was concluded that care throughout the production chain, storage, and commercialization of milk must be adopted to guarantee the microbiological safety of this food.

Anaphylaxis Induced by Exercise or Cold Stimulation with Hyperleukotrieneuria During a Challenge Testing Not Containing Food Ingestion

2020 ◽  
Author(s):  
Chikako Motomura ◽  
Koji Ide ◽  
Terufumi Shimoda ◽  
Hiroshi Odajima
Keyword(s):  
Cold Water ◽  
Challenge Test ◽  
Food Allergies ◽  
Food Ingestion ◽  
Post Challenge ◽  
Loading Test ◽  
Cold Stimulation ◽  
Plasma Adrenaline ◽  
Challenge Testing ◽  
Cold Drink

Abstract Background: Exercise-induced anaphylaxis (EIA) is rare and a potentially life-threatening disorder that can develop independently without food ingestion. Cold drinks can also trigger symptoms in some patients with cold-induced anaphylaxis. We present the case of a patient with exercise and cold-induced anaphylaxis that was diagnosed based on hyperleukotrieneuria in exercise loading and cold-drink challenge testing.Case presentation: A 12-year-old girl presented with acute flushing, cyanosis, swollen eyelids, and dyspnea after an endurance run in winter or swimming in a cold-water pool. She also developed dyspnea after having a cold drink. She had no history of food allergies or atopy. No association was noted between anaphylaxis and food intake in her history. On the 1st day, she ingested 200 mL cold water at a temperature of 5°C in 30 s, which did not trigger any symptomatic responses, but urinary LTE4 level increased (pre-challenge test 295 pg/mg.cr, post-challenge test 400 pg/mg.cr). On the 2nd day, she underwent the exercise loading test according to the Bruce protocol by increasing the power of exercise every 2 min using an ergometer. She had been fasting for >15 h and did not have breakfast. Just after the exercise loading test, the plasma adrenaline and noradrenaline increased. At 15min. after the exercise loading test, the plasma adrenaline and histamine (pre-challenge test 0.7 ng/mL, 15min.post-challenge test 81 ng/mL) rised sharply with anaphylaxis symptom accompaneid by increasing of urinary LTE4 (pre-challenge test 579 pg/mg.cr, post-challenge test 846 pg/mg.cr). After she was discharged, she was restricted from strenuous exercise especially in cold environments and prescribed an adrenaline autoinjector.Conclusion: To our knowledge, cold stimulation becomes a co-effector for EIA. Measurements of urinary LTE4 levels during challenge testing are useful to diagnose anaphylaxis induced by exercise or cold stimulation.

scholarly journals EVALUATION OF LISTERIA MONOCYTOGENES IN RAW BUFFALO MILK DURING PRIMARY PRODUCTION

2009 ◽  
Vol 1 (4) ◽  
pp. 49 ◽  
Author(s):  
N. Murru ◽  
M. Barile ◽  
M. Tozzi ◽  
C. Ceres ◽  
G. Aprea ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Primary Production ◽  
Buffalo Milk
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