Toward 6 log10 pulsed electric field inactivation with conductive plastic packaging material

Abstract

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. PRACTICAL APPLICATIONS In order to further minimize the risk of contaminating microorganisms, e.g., introduced during the packaging process, this new technology of pulsed electric field (PEF) treatment after packaging can be beneficial in reducing food safety incidents. This technique also makes hygienic packaging machines superfluous, which will reduce operational and investment costs. By proving that PEF inactivation through a plastic packaging material is possible, the first step toward PEF treatment after packaging has been taken. Important next steps toward industrial realization are extensive research on food grade conductive packaging films, PEF in-pack processing methodologies and microbial investigation of different microorganisms. © 2011 Wiley Periodicals, Inc