The application of microbubbles of pressured CO 2 greatly increased CO 2 concentration in the solution treated. By treatment at 6 MPa, 35ЊC and average residence time 15 min, L. brevis was completely inactivated at the level of dissolved CO 2 , ␥ м11 (␥, Kuenen's gas absorption coefficient). E. coli and S. cerevisiae required ␥ м 17, and T. versatilis required ␥ м 21 for complete inactivation. Z. rouxii could be sterilized at 20 MPa and 26. A comparison of the continuous and batch method showed that L. brevis was inactivated completely under pressured CO 2 Ͼ0.16 g/ cm 3 with the continuous method and Ͼ0.9 g/cm 3 with the batch method.

Aims: The effects of temperature and concentration of dissolved CO 2 on the inactivation of Saccharomyces cerevisiae were investigated using a plug-¯ow system. Methods and Results: Several combinations of pressure (4, 6, 8, 10 mega-Pa (MPa)) and temperature (30, 34, 36, 38°C) were used. The D-values obtained were 0á14 min at 8 MPa and 38°C, and 0á15 min at 10 MPa and 36°C. The log D-values were related linearly to the treatment temperature and to the dissolved CO 2 concentration. The thermal resistance constant (z CO 2 (T)) was 9á5°C in the media, including signi®cant levels of CO 2 , and the CO 2 resistance constant was z temp. (c) 7á2 c. Conclusions: This work has shown that inactivation followed ®rst-order death kinetics, and the effects of temperature and CO 2 concentration were consistent through the critical temperature and pressure of CO 2 . Therefore, it is feasible to estimate D-values at any temperature and any CO 2 concentration. Signi®cance and Impact of the Study: Non-thermal inactivation of micro-organisms in acidic beverages could be realized by the present technique.

Volatiles were removed from fish sauce by continuous-flow extraction with microbubbles of supercritical carbon dioxide. The extraction was done at 35 Њ Њ Њ Њ ЊC and CO 2 /sample flow ratio of 0.14 and 0.29 under pressures of 10 to 30 MPa. After the treatment at a CO 2 /sample flow ratio, 0.29 at 10 MPa, remaining percentage ((the concentration in treated sample/that in untreated one) ϫ ϫ ϫ ϫ ϫ 100) was 5.2% trimethylamine, 8.0% S-methyl ethanethioate, 30% dimethyldisulfide, 55 to 61% aliphatic aldehydes, and 25 to 42% carboxylic acids. The increase in CO 2 flow rate improved the extraction efficiency significantly, but no effect of pressure was observed. The odor intensities of treated samples were between 1/4 and 1/8 of the untreated fish sauce.