超音波の食品への応用

生理食塩水中に浮遊させたヒト由来のEscherichia coliに周波数700KHzの超音波を作用させたところ,試料の初期温度28～32℃のとき10分間照射で生残率0.83%,30分間照射で0.2%であった。　しかし初期温度17℃のときは,10分間で37.86%,30分間照射で8.1%であった。

市販の牛乳中に同種の菌を浮遊させたものについては超音波照射によって菌数の変化は殆んど見られなかった。

みかん果汁10%入りの市販の清涼飲料水の場合にはpH2.6のとき30分照射で初期温度32℃のとき生残率0.3%,18℃のとき同じく1.3%,pH5.6のときは32℃でかなり効果が低かった。

Escherichia coli, physiological saline suspensions, were exposed to supersonic waves of 700 KHz frequency. After the 10 minutes of exposure, in case of 28°C～32°C in initial temperature, the survivability was 0.83% and after 30 min. it was 0.2%. But at 17°C in initial temperature, after 10 minutes exposure we had 37.86%, and after 30 min., 8.1%. However, in the case of the commercialized milk suspension instead of physiological saline, supersonic waves exposure didn’t show almost any pasteurization effect. In the case of a commercialized cooling drink containing 10% of orange juice when the supersonic waves exposure was kept on for 30 minutes at an initial temperature of 32°C, the survivability was 0.3% at pH of 2.6, but the effect was insignificant at pH of 5.6.