Microbial Inactivation by Pulsed Electric Fields

Pulsed electric fields (PEF) were applied to neutral ginkgo cloudy juice to study the influence of the electric field strength, the treatment time and temperature on microbial inactivation. The results showed that microbial inactivation increased with the electric field strength, the treatment time and temperature. PEF treatment caused 3.39 and 4.44-log cycles reduction of coliforms and total plate counts, respectively, when pulse duration was 3 μs, the electric field strength 30 kV/cm, the treatment time 520 μs and the water bath temperature 15°C. Under the same conditions, the microbial shelf life of ginkgo cloudy juice was extended to 24 days at 4°C and 18 days at room temperature. A 3.7-log cycles reduction of the total yeast and mould counts was obtained by applying 390 μs of 30 kV/cm at 15°C.Yeast and mould cells were less resistant to PEF process than bacteria cells. The effect of heat generated during the PEF treatment was limited on microbial inactivation. Temperature and the induced heat by PEF had synergistic effects to microbial inactivation in cloudy ginkgo juice.

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Effect of pulsed electric fields on microbial inactivation and gelling properties of porcine blood plasma

Innovative Food Science & Emerging Technologies ◽

10.1016/j.ifset.2014.02.008 ◽

2014 ◽

Vol 23 ◽

pp. 87-93 ◽

Cited By ~ 8

Author(s):

Annika Boulaaba ◽

Martina Kiessling ◽

Stefan Töpfl ◽

Volker Heinz ◽

Günter Klein

Keyword(s):

Blood Plasma ◽

Electric Fields ◽

Pulsed Electric Fields ◽

Microbial Inactivation ◽

Porcine Blood ◽

Gelling Properties

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Combined Effects of Heat and PEF on Microbial Inactivation and Quality of Liquid Egg Whites

International Journal of Food Engineering ◽

10.2202/1556-3758.1256 ◽

2007 ◽

Vol 3 (4) ◽

Cited By ~ 18

Author(s):

Wei Zhao ◽

Ruijin Yang ◽

Yali Tang ◽

Rongrong Lu

Keyword(s):

Electric Fields ◽

Treatment Time ◽

Combined Treatment ◽

Pulsed Electric Fields ◽

Egg White ◽

Microbial Inactivation ◽

Processing Temperature ◽

Combined Effects ◽

Egg White Proteins ◽

Emulsifying Capacity

Combined effects of heat and pulsed electric fields treatment (20 and 40oC, 0-800 µs at 30 kV/cm) on microbial inactivation inoculated in egg whites were studied. Pulsed electric fields treatment time and processing temperature had profound effects on microbial inactivation. Pulsed electric fields treatment with a bipolar pulse (2 µs wide), an intensity of 30 kV/cm, a frequency of 100 Hz, the processing temperature of 40 oC and treatment time for 800 µs, was sufficient to achieve pasteurization conditions using S. enteritidis , E. coli and S. aureus, common spoilage and pathogenic micro-organisms in egg products. This treatment produced a non-significant (p>0.05) increase in foaming capacity and stability and an increase (p<0.05) in emulsifying capacity and stability. Surface free sulfhydryls and hydrophobicity of egg white proteins increased with the increment of the PEF treatment time due to the partial unfolding of egg white proteins. Almost 50 % of trypsin inhibitory activity of ovomucoid in liquid egg white was decreased when the treatment time extended to 800 µs. These results suggested that combined treatment of heat and pulsed electric fields could be applied to process liquid egg whites to get desired products.

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