Inactivation of Pseudomonas fluorescens in Skim Milk by Combinations of Pulsed Electric Fields and Organic Acids

2005 ◽  
Vol 68 (6) ◽  
pp. 1232-1235 ◽  
Author(s):  
JUAN J. FERNÁNDEZ-MOLINA ◽  
BILGE ALTUNAKAR ◽  
DANIELA BERMÚDEZ-AGUIRRE ◽  
BARRY G. SWANSON ◽  
GUSTAVO V. BARBOSA-CÁNOVAS
Keyword(s):  
Acetic Acid ◽  
Organic Acids ◽  
Pseudomonas Fluorescens ◽  
Propionic Acid ◽  
Electric Fields ◽  
Skim Milk ◽  
Pulsed Electric Fields ◽  
Treatment Temperature ◽  
Initial Concentration ◽  
Ph Range

Pseudomonas fluorescens suspended in skim milk was inactivated by application of pulsed electric fields (PEF) either alone or in combination with acetic or propionic acid. The initial concentration of microorganisms ranged from 105 to 106 CFU/ml. Addition of acetic acid and propionic acid to skim milk inactivated 0.24 and 0.48 log CFU/ml P. fluorescens, respectively. Sets of 10, 20, and 30 pulses were applied to the skim milk using exponentially decaying pulses with pulse lengths of 2 μs and pulse frequencies of 3 Hz. Treatment temperature was maintained between 16 and 20°C. In the absence of organic acids, PEF treatment of skim milk at field intensities of 31 and 38 kV/cm reduced P. fluorescens populations by 1.0 to 1.8 and by 1.2 to 1.9 log CFU/ml, respectively. Additions of acetic and propionic acid to the skim milk in a pH range of 5.0 to 5.3 and PEF treatment at 31, 33, and 34 kV/cm, and 36, 37, and 38 kV/cm reduced the population of P. fluorescens by 1.4 and 1.8 log CFU/ml, respectively. No synergistic effect resulted from the combination of PEF with acetic or propionic acid.

Inactivation of Listeria innocua and Pseudomonas fluorescens in Skim Milk Treated with Pulsed Electric Fields (PEF)

2019 ◽  
pp. 149-166
Author(s):  
J. J. Fernández-Molina ◽  
E. Barkstrom ◽  
P. Torstensson ◽  
G. V. Barbosa-Cánovas ◽  
B. G. Swanson
Keyword(s):  
Pseudomonas Fluorescens ◽  
Electric Fields ◽  
Skim Milk ◽  
Pulsed Electric Fields ◽  
Listeria Innocua

INACTIVATION OF LISTERIA INNOCUA AND PSEUDOMONAS FLUORESCENS BY PULSED ELECTRIC FIELDS IN SKIM MILK: ENERGY REQUIREMENTS

2006 ◽  
Vol 29 (6) ◽  
pp. 561-573 ◽  
Author(s):  
JUAN J. FERNÁNDEZ-MOLINA ◽  
DANIELA BERMÚDEZ-AGUIRRE ◽  
BILGE ALTUNAKAR ◽  
BARRY G. SWANSON ◽  
GUSTAVO V. BARBOSA-CÁNOVAS
Keyword(s):  
Pseudomonas Fluorescens ◽  
Electric Fields ◽  
Skim Milk ◽  
Pulsed Electric Fields ◽  
Listeria Innocua ◽  
Energy Requirements

On-Chip Indirect Detection of Non-Fluorescent Analytes Using Fluorescent Spacers

2007 ◽  
Author(s):  
Tarun K. Khurana ◽  
Juan G. Santiago
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Lower Bound ◽  
Organic Acids ◽  
Indirect Detection ◽  
Phenylpropionic Acid ◽  
Initial Concentration ◽  
On Chip

We present a technique that accomplishes on-chip preconcentration, separation and indirect detection of nonfluorescent analytes by leveraging isotachophoresis (ITP) and a set of fluorescent species termed spacers. The non-fluorescent analyte zones are detected as dark zones/gaps between fluorescent spacer zones. The length of this gap quantifies the initial concentration of the non-fluorescent analyte and mobilities of the fluorescent spacers on either side provide the upper and lower bound for the analyte mobility. We have successfully demonstrated separation and detection of amino acids, serine and phenylalanine, as well as other organic acids, acetic acid and phenylpropionic acid with this technique. Using three fluorescent spacers, we were able to detect ∼10 μM concentration of non-fluorescent analytes.

Independent Effects of Acetic Acid and pH on Survival ofEscherichia coli in Simulated Acidified Pickle Products†‡

2004 ◽  
Vol 67 (1) ◽  
pp. 12-18 ◽  
Author(s):  
F. BREIDT ◽  
J. S. HAYES ◽  
R. F. McFEETERS
Keyword(s):  
Acetic Acid ◽  
Organic Acids ◽  
Acid Resistance ◽  
Ofescherichia Coli ◽  
Acid Solutions ◽  
Specific Effects ◽  
Effects Of Ph ◽  
Ph Range ◽  
Independent Effects ◽  
D Values

Our objective was to determine the effects of organic acids and pH on the rate at which selected strains ofEscherichia coli O157:H7 die in acid solutions representative of acidified pickle products (pH < 4.6). We used gluconic acid/sodium gluconate (pKa = 3.7) as a noninhibitory buffer to maintain pH at selected values in the absence of other organic acids. This was possible because we found that the inhibitory effects of this acid onE. coli strains at pH 3.1 were independent of acid concentration over a range of 2 to 200 mM. By this method, the lethal effects of acetic acid solutions (100 to 400 mM) at selected pH values between 3.1 and 4.1 were compared with the effects of pH alone (as determined using gluconate buffer). We found D-values were two- to fourfold lower with acetic acid compared with the effect of pH alone for simulated pickle brines in this pH range. Glutamic acid, an amino acid that is known to enhance acid resistance inE. coli and is a component of pickle brines, protected theE. coli strains from the specific effects of acetic acid.

scholarly journals Inactivation of Mycobacterium paratuberculosis by Pulsed Electric Fields

2001 ◽  
Vol 67 (6) ◽  
pp. 2833-2836 ◽  
Author(s):  
Neil J. Rowan ◽  
Scott J. MacGregor ◽  
John G. Anderson ◽  
Douglas Cameron ◽  
Owen Farish
Keyword(s):  
Electric Fields ◽  
Pulsed Electric Fields ◽  
Cellular Level ◽  
Treatment Temperature ◽  
Cow’S Milk ◽  
Mycobacterium Paratuberculosis ◽  
Cow's Milk ◽  
High Temperature Short Time ◽  
Peptone Water ◽  
Short Time

ABSTRACT The influence of treatment temperature and pulsed electric fields (PEF) on the viability of Mycobacterium paratuberculosiscells suspended in 0.1% (wt/vol) peptone water and in sterilized cow's milk was assessed by direct viable counts and by transmission electron microscopy (TEM). PEF treatment at 50°C (2,500 pulses at 30 kV/cm) reduced the level of viable M. paratuberculosis cells by approximately 5.3 and 5.9 log10 CFU/ml in 0.1% peptone water and in cow's milk, respectively, while PEF treatment of M. paratuberculosisat lower temperatures resulted in less lethality. Heating alone at 50°C for 25 min or at 72°C for 25 s (extended high-temperature, short-time pasteurization) resulted in reductions ofM. paratuberculosis of approximately 0.01 and 2.4 log10 CFU/ml, respectively. TEM studies revealed that exposure to PEF treatment resulted in substantial damage at the cellular level to M. paratuberculosis.

scholarly journals Impact of preoperative fecal short chain fatty acids on postoperative infectious complications in esophageal cancer patients

2019 ◽  
Author(s):  
Masaaki Motoori ◽  
Koji Tanaka ◽  
Keijiro Sugimura ◽  
Hiroshi Miyata ◽  
Takuro Saito ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Organic Acids ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Bacterial Translocation ◽  
Infectious Complications ◽  
The Body ◽  
Intestinal Environment

Abstract Background: The intestinal epithelial barrier allows absorption of dietary nutrients and prevents passage of pathogens and toxins into the body. Severe insults have a negative impact on the intestinal environment, which may decrease intestinal barrier function and cause bacterial translocation. Bacterial translocation, which can cause infectious complications, is the passage of microbes from the gastrointestinal tract across the mucosal barrier to extraintestinal sites. The aim of this study was to investigate the correlation between concentrations of preoperative fecal organic acids and the occurrence of postoperative infectious complications in patients with esophageal cancer. Methods: Fifty-five patients with esophageal cancer who underwent esophagectomy were enrolled in this study. All patients were administered perioperative synbiotics. Perioperative clinical characteristics and concentrations of preoperative fecal organic acids were compared between patients with or without postoperative infectious complications. Results: Postoperative infectious complications occurred in 10 patients. In patients with complications, the concentrations of acetic acid and propionic acid were significantly lower than in patients without complications (p=0.044 and 0.032, respectively). The concentration of butyric acid was nonsignificantly lower, while the concentration of lactic acid was nonsignificantly higher in patients with complications. The calculated gap between the concentrations of fecal acetic acid plus propionic acid plus butyric acid minus lactic acid was significantly lower in patients with complications. Multivariate analysis revealed that a low gap between acetic acid plus propionic acid plus butyric acid minus lactic acid was an independent risk factor for postoperative infectious complications (p=0.027). Conclusions : Preoperative fecal concentrations of organic acids had a clinically important impact on the occurrence of postoperative infectious complications in patients with esophageal cancer. To reduce postoperative infectious complications, it may be useful to modulate the intestinal environment and maintain concentrations of fecal organic acids before surgery.

scholarly journals Impact of preoperative fecal short chain fatty acids on postoperative infectious complications in esophageal cancer patients

2020 ◽  
Author(s):  
Masaaki Motoori ◽  
Koji Tanaka ◽  
Keijiro Sugimura ◽  
Hiroshi Miyata ◽  
Takuro Saito ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Organic Acids ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Bacterial Translocation ◽  
Infectious Complications ◽  
The Body ◽  
Intestinal Environment

Abstract Background: The intestinal epithelial barrier allows absorption of dietary nutrients and prevents passage of pathogens and toxins into the body. Severe insults have a negative impact on the intestinal environment, which may decrease intestinal barrier function and cause bacterial translocation. Bacterial translocation, which can cause infectious complications, is defined as the passage of microbes from the gastrointestinal tract across the mucosal barrier to extraintestinal sites. The aim of this study was to investigate the correlation between concentrations of preoperative fecal organic acids and the occurrence of postoperative infectious complications in patients with esophageal cancer. Methods: Fifty-five patients with esophageal cancer who underwent esophagectomy were enrolled in this study. Perioperative synbiotics were administered to all patients. Perioperative clinical characteristics and concentrations of preoperative fecal organic acids were compared between patients with and without postoperative infectious complications. Results: Postoperative infectious complications occurred in 10 patients. In patients with complications, the concentrations of acetic acid and propionic acid were significantly lower than in patients without complications (p=0.044 and 0.032, respectively). The concentration of butyric acid was nonsignificantly lower in patients with complications, while the concentration of lactic acid was nonsignificantly higher. The calculated gap between the concentrations of fecal acetic acid plus propionic acid plus butyric acid minus lactic acid was significantly lower in patients with complications. Multivariate analysis revealed that a low gap between acetic acid plus propionic acid plus butyric acid minus lactic acid was an independent risk factor for postoperative infectious complications (p=0.027). Conclusions : Preoperative fecal concentrations of organic acids had a clinically important impact on the occurrence of postoperative infectious complications in patients with esophageal cancer. To reduce postoperative infectious complications, it may be useful to modulate the intestinal environment and maintain concentrations of fecal organic acids before surgery.

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