Combined carbon dioxide and high pressure inactivation of pectin methylesterase, polyphenol oxidase, Lactobacillus plantarum and Escherichia coli

High pressure processing (HPP) and CO(2) have both been shown to increase food product shelf-life. CO(2) was added at approximately 0.2 molar % to solutions processed at 300 to 800 MPa in order to further inactivate pectin methylesterase (PME), polyphenol oxidase (PPO), L. plantarum ATCC 8014, and E. coli K12. An interaction was found between CO(2) and pressure at 25degreesC and 50degreesC for PME and PPO, respectively. Activity of PPO was decreased by CO(2) at all pressure treatments. The interaction between CO(2) and pressure was significant for L. plantarum with a significant decrease in survivors due to the addition of CO(2) at all pressures studied. No significant effect on E. coli survivors was seen with CO(2) addition.