Inactivation kinetics of Listeria innocua ATCC 33090 at various temperature heating-up and pressure building-up rates

초록

The effects of temperature heating-up rate and pressure building-up phase on the inactivation of Listeria innocua ATCC 33090 were evaluated in buffered peptone water. The number of L. innocua was reduced by 5.57 and 6.52 log CFU/ mL during the nonisothermal treatment (the come-up time followed by isothermal process) and the isothermal treatment, respectively, at 60 degrees C. When compared to the isothermal treatment (0.76 < D value < 0.96), L. innocua exposed at the nonisothermal treatment (1.58 < D value < 2.31) became more resistant to heat. The come-up time reductions in numbers of L. innocua significantly increased with increasing the heating rates (p < 0.05). The pronounced reduction was observed by more than 5 log CFU/mL at 33.2 degrees C/min of temperature heating-rate. The effect of the combined high pressure and thermal processing on the inactivation of L. innocua increased with increasing pressure and temperature. At all temperature levels from 40 to 60 degrees C under 700 MPa, L. innocua was not detected by enrichment culture (> 7 log reduction).

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