Effects of high hydrostatic pressure processing on microbial inactivation in fresh fruit and vegetable juice

To prevent the fresh fruit and vegetable juices from being infected by microorganisms and decaying, high hydrostatic pressure, as an alternative sterilization technology was applied to reduce the amount of microorganisms, extend the shelf life and ensure the safety of products. Effects of high hydrostratic pressure (HHP) processing on change of colony forming unit in fresh apple juice and carrot juice during the storage were investegated to ensure the biosafety. The results showed that HHP was more suitable for fresh apple juice at lower pH value than carrot juice at neutral pH value. With the increase of pressure and holding time, the amount of microorganisms decreased significantly (P＜0.05). Furthermore, the HHP-treated apple juice presented a longer shelf life than carrot juice did under the similar conditions. The fresh apple juice treated by HHP at 400 MPa for 15 min can be stored at 4℃ for over seven days and still remains edible. However, the fresh carrot juice treated by HHP at 400 MPa for 45 min can only be stored at 4℃ for three days.