Construction and Testing of Implant Carrier Particles for Validation of Multiphase Aseptic Processes

Abstract

Aseptic processing of low-acid foods containing large particles is an emerging technology. Most multiphase process validation methods employ simulated particles to contain residence time tags, thermo-sensitive implants and/or bio-loads for temperature detection, time-temperature integration, and bactericidal efficacy confirmation. Such particles need to have conservative (fast-moving and slow-heating) characteristics to compare them with real food particles for thermal treatment. This study was conducted to fabricate and test (by heat penetration studies) conservative simulated particles which serve as carriers for thermo-sensitive implants and bio-loads in the validation procedure required for aseptic processing of shelf stable low-acid multiphase foods. A custom developed CPD (Conservative Particle Design) software was used to determine the minimum wall thickness (~ 2 mm) and cavity dimensions of half inch cubic particles for validation of aseptic processing of foods containing half inch cubic potato, carrot and other vegetable pieces. These particles were fabricated from PP (polypropylene) and PMP (polymethylpentene) polymers and they exhibited conservative heat penetration characteristics when compared with various real food particles. Duplicate samples of simulated and real food particles were fitted with thermocouples and heated (< 127 degree C) under pressurized (autoclave, 24 psi) conditions. The method developed in this study can be used for experimental validation of the safety of aseptic processing of multiphase foods and would reduce the cost and complexity of process documentation and filing with regulatory agencies and bring aseptic multiphase foods closer to commercial reality.