Inactivation of Listeria monocytogenes in Milk by Pulsed Electric Field

1998 ◽  
Vol 61 (9) ◽  
pp. 1203-1206 ◽  
Author(s):  
LAURA D. REINA ◽  
Z. TONY JIN ◽  
Q. HOWARD ZHANG ◽  
AHMED E. YOUSEF
Keyword(s):  
Listeria Monocytogenes ◽  
Field Strength ◽  
Electric Field ◽  
High Voltage ◽  
Foodborne Pathogens ◽  
Treatment Time ◽  
Skim Milk ◽  
Pulsed Electric Field ◽  
Lethal Effect ◽  
Treatment Temperature

Pasteurized whole, 2%, and skim milk were inoculated with Listeria monocytogenes Scott A and treated with high-voltage pulsed electric field (PEF). The effects of milk composition (fat content) and PEF parameters (electric field strength, treatment time, and treatment temperature) on the inactivation of the bacterium were studied. No significant differences were observed in the inactivation of L. monocytogenes Scott A in three types of milk by PEF treatment. With treatment at 25°C, 1- to 3-log reductions of L. monocytogenes were observed. PEF lethal effect was a function of field strength and treatment time. Higher field strength or longer treatment time resulted in a greater reduction of viable cells. A 4-log reduction of the bacterium was obtained by increasing the treatment temperature to 50°C. Results indicate that the use of a high-voltage PEF is a promising technology for inactivation of foodborne pathogens.

scholarly journals Pulsed Electric Field (PEF) Enhances Iron Uptake by the Yeast Saccharomyces cerevisiae

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 850
Author(s):  
Karolina Nowosad ◽  
Monika Sujka ◽  
Urszula Pankiewicz ◽  
Damijan Miklavčič ◽  
Marta Arczewska
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Electric Field ◽  
Metal Ion ◽  
Treatment Time ◽  
Control Sample ◽  
Pulsed Electric Field ◽  
Yeast Cells ◽  
Iron Ions ◽  
Metal Ion Binding ◽  
Yeast Saccharomyces Cerevisiae

The aim of the study was to investigate the influence of a pulsed electric field (PEF) on the level of iron ion accumulation in Saccharomyces cerevisiae cells and to select PEF conditions optimal for the highest uptake of this element. Iron ions were accumulated most efficiently when their source was iron (III) nitrate. When the following conditions of PEF treatment were used: voltage 1500 V, pulse width 10 μs, treatment time 20 min, and a number of pulses 1200, accumulation of iron ions in the cells from a 20 h-culture reached a maximum value of 48.01 mg/g dry mass. Application of the optimal PEF conditions thus increased iron accumulation in cells by 157% as compared to the sample enriched with iron without PEF. The second derivative of the FTIR spectra of iron-loaded and -unloaded yeast cells allowed us to determine the functional groups which may be involved in metal ion binding. The exposure of cells to PEF treatment only slightly influenced the biomass and cell viability. However, iron-enriched yeast (both with or without PEF) showed lower fermentative activity than a control sample. Thus obtained yeast biomass containing a high amount of incorporated iron may serve as an alternative to pharmacological supplementation in the state of iron deficiency.

Inactivation of E. coli K12 in apple juice by high voltage pulsed electric field

2003 ◽  
Vol 217 (5) ◽  
pp. 434-437 ◽  
Author(s):  
B. Sen Gupta ◽  
F. Masterson ◽  
T. R. A. Magee
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
Apple Juice ◽  
Pulsed Electric Field ◽  
E Coli

scholarly journals Quality stability and sensory attributes of apple juice processed by thermosonication, pulsed electric field and thermal processing

2016 ◽  
Vol 23 (3) ◽  
pp. 265-276 ◽  
Author(s):  
Alifdalino Sulaiman ◽  
Mohammed Farid ◽  
Filipa VM Silva
Keyword(s):  
Antioxidant Activity ◽  
Electric Field ◽  
Sensory Analysis ◽  
Thermal Processing ◽  
Apple Juice ◽  
Treatment Time ◽  
Pulsed Electric Field ◽  
Color Difference ◽  
Soluble Solids ◽  
Total Color Difference

Worldwide, apple juice is the second most popular juice, after orange juice. It is susceptible to enzymatic browning spoilage by polyphenoloxidase, an endogenous enzyme. In this study, Royal Gala apple juice was treated by thermosonication (TS: 1.3 W/mL, 58 ℃, 10 min), pulsed electric field (PEF: 24.8 kV/cm, 60 pulses, 169 µs treatment time, 53.8 ℃) and heat (75 ℃, 20 min) and stored at 3.0 ℃ and 20.0 ℃ for 30 days. A sensory analysis was carried out after processing. The polyphenoloxidase activity, antioxidant activity and total color difference of the apple juice were determined before and after processing and during storage. The sensory analysis revealed that thermosonication and pulsed electric field juices tasted differently from the thermally treated juice. Apart from the pulsed electric field apple juice stored at room temperature, the processed juice was stable during storage, since the pH and soluble solids remained constant and fermentation was not observed. Polyphenoloxidase did not reactivate during storage. Along storage, the juices’ antioxidant activity decreased and total color difference increased (up to 6.8). While the antioxidant activity increased from 86 to 103% with thermosonication and was retained after pulsed electric field, thermal processing reduced it to 67%. The processing increased the total color difference slightly. No differences in the total color difference of the juices processed by the three methods were registered after storage. Thermosonication and pulsed electric field could possibly be a better alternative to thermal preservation of apple juice, but refrigerated storage is recommended for pulsed electric field apple juice.

High-Voltage Pulsed Electric Field Preprocessing Enhances Extraction of Starch, Proteins, and Ash from Marine Macroalgae Ulva ohnoi

2019 ◽  
Vol 7 (20) ◽  
pp. 17453-17463 ◽  
Author(s):  
Meghanath S. Prabhu ◽  
Klimentiy Levkov ◽  
Yoav D. Livney ◽  
Alvaro Israel ◽  
Alexander Golberg
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
Pulsed Electric Field ◽  
Marine Macroalgae ◽  
Ulva Ohnoi
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