A continuous plant for food preservation by high pressure CO2

A continuous plant specifically designed for microbial inactivation by high pressure CO2 is presented. The pilot plant was built to check the high pressure CO2 pasteurization method on pumpable foodstuffs in an apparatus suitable for development at industrial scale.Results are reported on both simple and complex substrates. First, model suspension with selected microbial strain as test microorganism was tested at 110 bar, 27 °C and 36 °C, then fresh foodstuffs were treated in their natural condition. The operating temperature was always between 26 and 40 °C, the pressure between 80 and 110 bar.In physiological saline solution, inoculated with Bacillus subtilis, total inactivation degree was achieved. The effectiveness of the proposed technology for food pasteurization was successfully checked at particularly mild conditions on natural grape must. The high pressure CO2 pasteurization was effective with natural red orange juice and commercial inoculated tomato paste as well, whereas natural tomato paste proved to be resistant to the CO2 treatment.