University of Guelph

Shirley Yuet Ho

Gauri S Mittal

Mansel W Griffiths

James D Cross

A method and apparatus for electrically treating foodstuffs flowing through a treatment chamber with low energy, high voltage electrical pulses for non-thermal pasteurization and/or sterilization. Instant-charge-reversal electrical pulses are applied to a foodstuff located between two electrodes in a treatment chamber, each electrical pulse having a pulse width in a range from about 1 to 5 .mu.s with vertically rising voltage to a peak followed immediately with a decreasing voltage through zero volts and continuing to a voltage peak of opposite polarity and rising vertically back to zero volts. The electrical pulses are very low energy (0.1-25 Joules/pulse) and the field strengths are in the range 15 kVolts/cm to 120 kVolts/cm. This instant-charge-reversal electrical pulse is shown to have a much greater microbial killing power compared to other pulse waveforms used to treat foodstuff. The apparatus uses an electrode arrangement including a cylindrical inner electrode and an annular disc with the cylindrical electrode inserted through the hole in the disc.

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Toronto, Canada

Shirley Yuet Ho