Utilization of Bioindicators to Validate Thermal Processes: Case Study Example for Small Canning Processors

Introduction: Small canning processors have limited resources to validate designed thermal processes. There is also limited published literature demonstrating the use of bioindicators to validate microbial inactivaton of "soups" in retortable pouches. Small canning establishments would benefit to know their new product/process can be assured of effective commercial sterilization by observing actual microbial inactivation by using bioindicators.

Purpose: The purpose of this study is to evaluate commercially available bioindicators to validate thermal processes and to demonstrate how a validation can be done by using a case study in a particulate food product such as a soup

Methods: At least 5 retortable pouches containing soup were subjected to a thermal process at 250F in a steam retort. The thermal process was repeated at least 3 times in order to determine the process time to achieve an Fo  of at least 5 min. The thermal process is to be validated by using bioindicators (Geobacillus stearothermopilus 7953 (MesaLabs supplier) by follwoing recommended FDA and MesaLabs instructions.

Results: A minimum process time of 30 min at 250F is necessary to achieve the minimum lethality equivalent to an Fo of 5 min.

Significance: the use of bioindicators is a proven method to validate thermal processes; however, there is a lack of available literature to small canners informing them about the use of bioindicators to demonstrate the safety of their products has been achieved. The case study will be published in a format readily available to small canners including some form of an Extension or Public Service publication.