Inactivation of yeast and bacteria using combinations of radio frequency electric fields and ultraviolet light

2020 ◽  
Vol 44 (4) ◽  
Author(s):  
David J. Geveke
Keyword(s):  
Radio Frequency ◽  
Ultraviolet Light ◽  
Electric Fields ◽  
Radio Frequency Electric Fields

Inactivation of Lactobacillus plantarum in Apple Cider, Using Radio Frequency Electric Fields†

2009 ◽  
Vol 72 (3) ◽  
pp. 656-661 ◽  
Author(s):  
DAVID J. GEVEKE ◽  
JOSHUA GURTLER ◽  
HOWARD Q. ZHANG
Keyword(s):  
Radio Frequency ◽  
Lactobacillus Plantarum ◽  
Electric Fields ◽  
Treatment Time ◽  
Hold Time ◽  
Electrical Energy ◽  
Gram Positive ◽  
Apple Cider ◽  
Gram Positive Bacteria ◽  
Radio Frequency Electric Fields

Radio frequency electric fields (RFEF) nonthermal processing effectively inactivates gram-negative bacteria in juices, but has yet to be shown effective at reducing gram-positive bacteria. Apple cider containing Lactobacillus plantarum ATCC 49445, a gram-positive bacterium, was RFEF processed under the following conditions: field strength of 0.15 to 15 kV/cm, temperature of 45 to 55°C, frequency of 5 to 65 kHz, treatment time of 170 μs, and holding time of 5 to 50 s. The effect of refrigerating the inoculated cider prior to processing, the extent of sublethal injury, and the effect of storing the treated cider for 35 days were investigated. The population of L. plantarum was reduced by 1.0 log at 15 kV/cm, 20 kHz, and 50°C, with a 5-s hold time. There is a synergistic effect between RFEF and heat above 50°C. Inactivation significantly (P < 0.05) increased as frequency was decreased from 65 to 5 kHz. Inactivation increased linearly with field above 8 kV/cm. Holding cider at 55°C after RFEF treatment for 5 and 50 s resulted in 2.5- and 3.1-log reductions, respectively. The surviving population was composed of 1.4-log sublethally injured cells. Storing processed cider at 4°C for 35 days steadily and significantly (P < 0.05) reduced L. plantarum from 4.5 to 0.9 log CFU/ml. The electrical energy density was 51 J/ml. This provides the first evidence that nonthermal RFEF processing inactivates gram-positive bacteria, and that surviving cells may die off during refrigerated storage.

scholarly journals Transient propagation dynamics of flowing plasmas accelerated by radio-frequency electric fields

2017 ◽  
Vol 24 (5) ◽  
pp. 050703 ◽  
Author(s):  
James Dedrick ◽  
Andrew Robert Gibson ◽  
Dmytro Rafalskyi ◽  
Ane Aanesland
Keyword(s):  
Radio Frequency ◽  
Electric Fields ◽  
Radio Frequency Electric Fields ◽  
Propagation Dynamics

scholarly journals Heterodyne detection of radio-frequency electric fields using point defects in silicon carbide

2019 ◽  
Vol 115 (4) ◽  
pp. 043105 ◽  
Author(s):  
Gary Wolfowicz ◽  
Christopher P. Anderson ◽  
Samuel J. Whiteley ◽  
David D. Awschalom
Keyword(s):  
Silicon Carbide ◽  
Radio Frequency ◽  
Electric Fields ◽  
Point Defects ◽  
Heterodyne Detection ◽  
Radio Frequency Electric Fields
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