Multi-pulsed high hydrostatic pressure inactivation of microorganisms: A review

• This contribution compiles the studies about the mpHHP inactivation of microorganisms.
• The mpHHP treatment inactivates the viruses, yeasts, bacteria and spores effectively.
• Pulse number, pulse holding time, and compression and decompression rates are important factors during the mpHHP treatment.

Multi-pulsed high hydrostatic pressure (mpHHP) treatment, which has been applied for two decades, is broadly more effective than the classical or single-pulsed HHP (spHHP) for inactivation of viruses, yeasts, bacterial cells, and fungal and bacterial spores. The effectiveness of the mpHHP treatment could be increased with a smart choice of pressure, initial and target temperature, pulse number, pulse holding time, and compression and decompression rates. The effectiveness of the mpHHP treatment is well documented and at the moment it seems that it is not feasible to apply the mpHHP treatment commercially for the food industry. However, with the availability of new technologies it may be possible to speed up the HHP processing by decreasing compression and decompression rates and to produce repeated pulses of high pressure. The mpHHP treatment could be very beneficial to the food industry and could replace the pressure-assisted thermal sterilization (PATS) with lower pressure and temperature values.Industrial relevanceMost of the studies have shown that the mpHHP treatment could be used to inactivate the microrganisms in foods at lower pressure values than the spHHP treatment for the same amount of holding time but for a longer processing time (including the compression and decompression periods of the pulses). The mpHHP treatment has a potential to sterilize the food products with the help of developing technology if the optimization between pressure, temperature, number of pulses, pulse holding time and compression and decompression rates could be possible.