Mechanisms of endospore inactivation under high pressure

• Spore inactivation under pressure is a multi-step inactivation.
• Dipicolinic acid (DPA) release is the first indicator of the loss of heat resistance of spores under high pressure (HP).
• Moderate pressures and temperatures induce a non-nutrient germination with cortex degradation.
• HPs and temperatures presumably cause structural changes in the inner spore membrane.

It is well known that spore germination and inactivation can be achieved within a broad temperature and pressure range. The existing literature, however, reports contradictory results concerning the effectiveness of different pressure–temperature combinations and the underlying inactivation mechanism(s). Much of the published kinetic data are prone to error as a result of unstable process conditions or an incomplete investigation of the entire inactivation pathway. Here, we review this field of research, and also discuss an inactivation mechanism of at least two steps and propose an inactivation model based on current data. Further, spore resistance properties and matrix interactions are linked to spore inactivation effectiveness.