Prevention of electrode fouling in high electric field systems for killing microorganisms in food products

A system for killing microorganisms in a food product, said food product containing a fouling agent that agglomerates on an electrode in response to the passing of a net charge between the electrode and the food product, said agglomeration causing fouling of the electrode, said system including:

• means for establishing a supply of food product in electrical contact with the electrode;
• means for delivering a first charge from a charge supply circuit to the electrode;
• and
• means for delivering a second charge to the charge supply circuit from the electrode;
• and
• means for making said first charge and said second charge substantially equal charges such that the net charge transferred to the electrode over a prescribed period of time is approximately zero;
• whereby the fouling of the electrode is reduced.

An apparatus for killing microorganisms in a food product, said apparatus including:

• an electrode in electrical contact with a supply of the food product, which supply of food product contains a fouling agent that agglomerates on the electrode in response to the transfer of a net charge between the electrode and the supply, said agglomeration causing the fouling of the electrode;
• a pulse forming network coupled to the electrode, wherein the pulse forming network is capable of delivering a pulse voltage signal to the electrode;
• a power supply coupled to the pulse forming network, wherein said power supply charges the pulse forming network to the pulse voltage signal;
• a charge zeroing circuit coupled to the electrode, wherein the charge zeroing circuit delivers a net charge zeroing voltage signal to the electrode;
• and
• a switch coupled to the pulse forming network and to the charge zeroing circuit,
• said switch having a first state in response to which the pulse voltage signal is delivered to the electrode, which pulse voltage signal causes a first charge to be transferred to the electrode, and
• said switch having a second state in response to which the net charge zeroing voltage signal is delivered to the electrode, which net charge zeroing voltage signal causes a second charge to be transferred from the electrode,
• said first charge being approximately equal to said second charge such that the net charge delivered to the electrode in response to the switch serially assuming the first and second states is approximately zero;
• whereby the fouling of the electrode is reduced.

An apparatus for reducing the fouling of an electrode that is in electrical contact with a supply of food product, wherein the supply of food product contains a fouling agent that agglomerates on the electrode in response to the passing of a net charge to the electrode, said agglomeration causing the fouling of the electrode, said apparatus comprising:

• a charge supply circuit coupled to the electrode;
• a switch coupled to the charge supply circuit,
• said switch having a first state in which the switch configures the charge supply circuit to deliver a charge to the electrode,
• said switch having a second state in which the switch configures the charge supply to substantially absorb the charge from the electrode;
• and
• controller means coupled to the switch for controlling the switch to assume the first state and the second state so that the charge delivered to the electrode is approximately zero over a prescribed period of time;
• whereby the fouling of the electrode is reduced.