High-pressure food processing, using pressures between 1 and 10 kbar, permits preservation of aroma and vitamins, improvement of textural and sensory properties, and removal of harmful bacteria. The process must be carefully monitored, however, as localized variations in pressure or temperature can significantly influence the removal of bacteria. The process must therefore be uniform, especially in the health-sensitive field of microbial inactivation.

At TU München’s Chair of Fluid Mechanics and Process Control, we are investigating the effect of the fluid dynamics on bacteria during high-pressure food processing. Our research focuses on a 6.3-litre high-pressure chamber that is used to pressurize liquid food contained in five packages, placed on different shelves in the chamber. The chamber is filled with a pressure transferring liquid (in our case water) until the desired pressure level (4 kbar) is reached. The pressure is maintained for about 20 minutes - the time needed to kill the bacteria.

Since experimental methods for investigation at very high pressures, especially for industrial chambers, are not readily available, we have chosen CFD as a means to investigate scale-up and non-uniformity.