T1-11 Sterilization Enhancement of Low-concentrated Ozone Gas Using Micro-bubbles by Surface-active Agents

Monday, August 4, 2014: 11:30 AM
Room 111-112 (Indiana Convention Center)
Shinichi Watanabe, Lion Corporation, Tokyo, Japan
Yoshikuni Takeuchi, Lion Corporation, Tokyo, Japan
Sonoko Nishimura, Lion Hygiene Corporation, Tokyo, Japan
Tomonari Suekuni, Lion Corporation, Tokyo, Japan
Norio Tobori, Lion Corporation, Tokyo, Japan
Introduction: Ozone gas is a strong oxidant. Ozone has possibilities of being used as an alternate technique of chloride reagents that is used to sterilize fresh-cut vegetables, but subtle ozone water does not have a sufficient effect on sterilization. Thus, to enhance sterilization performance of ozone is required.

Purpose: The objective of this study is to develop new technology that enhances sterilization performance of low-concentrated ozone gas using micro-bubbles by surface-active agents.

Methods: The testing bacteria solution was prepared by mixing 20 g of commercial non-bleach bean sprouts and 90 ml of sterilized saline with a homogenizer.  This solution included 5 log CFU/ml of viable bacteria, and pH was 6.5.  Two types of ozone solutions were evaluated; 1) The mixed solution that consists of dissolved ozone water and the bacteria solution. 2) The micro-bubble ozone solution that was 400 ml of bacteria solution including 5 g/l triacetin as a surface-active agent, and 0.063 mg/l of ozone gas was aerated into solution with a flow rate of 1.0 l/min for 2.5 minutes using a porous glass. Viable bacteria surviving in these solutions were counted to evaluate the sterilization performance.

Results: In the case of mixed solution that initially has dissolved 0.5 mg/l of ozone, 3.83 ± 0.02 log CFU/ml of viable bacteria was detected. Adding triacetin to this solution, the viable bacteria was 3.56 ± 0.04 log CFU/ml, and addition of triacetin showed little effect on performance. On the other hand, in the case of micro-bubble ozone solution, viable bacteria were not detected. Because the amount of supplied ozone of micro-bubble treatment was sufficiently lower than that of mixed solution, it can be assumed that micro-bubble generation by surface-active agents enhance the sterilization performance of ozone gas.

Significance: Micro-bubble generation utilizing surface-active agents is an effective way to enhance sterilization performance of ozone.