Generally, high grade products such as pulsed electric field (PEF) treated fruit juices are packaged after their preservative treatment. However, PEF treatment after packaging could avoid recontamination of the product and becomes feasible when electric field pulses of sufficient magnitude can be generated inside closed food containments. Microbial inactivation of 2 log10 was proved by using an electrically conductive plastic packaging material, and in this contribution it is shown that inactivation toward pasteurization level is achievable. Therefore, a series of microbial experiments with Lactobacillus plantarum at different energy levels were performed. The obtained microbial data with the plastic material have been compared with inactivation models from literature as well as with reference experiments. All treatments were done at ~2.3 kV/mm, with treatment times between 10¿600 µs, and the thermal load was below 38C. The maximum obtained microbial inactivation with the plastic packaging material was 5.9 log10 with a specific energy of 255 J/mL.@en

Nowadays Pulsed Electric Field (PEF) treatment of food needs to be performed prior to packaging, either hygienic or aseptic packaging is necessary. New techniques for PEF treatment after packaging can be considered when plastic conductive (film) electrodes can be integrated within the package, so that the package and the product can be treated as a whole. This paper describes a newly developed treatment chamber, which can be used to test the ability of any arbitrary plastic packaging film to be used as electrodes for PEF treatment. Tests with a flexible commercially available electrically conductive copolymer film showed that reduction of Lactobacillus plantarum by PEF was possible. This heat sealable film obeys the mechanical properties of a polymer; however it has an electrical conductivity of 0.75 S m¿ 1 and approximately 2.3% of the surface area is electrically conductive. The maximum obtained inactivation was 2.1 log10 with a specific energy of 17 J ml¿ 1. The microbial experiments gave a consistent outcome compared with finite element simulations and with models from literature. Further research to reach real pasteurisation levels is needed as well as issues concerning utilisation of these film electrodes.@en