(572b) Modeling Pressure and Thermal Sensitivity of Bacillus Amyloliquefaciens Spores in Mashed Egg Patties during Presure-Assisted Thermal Processing

Combined pressure-thermal resistance of Bacillus amyloliquefaciens spores in mashed egg patties during presure-assisted thermal processing (PATP) was estimated. Mashed egg patties (0.9-g samples) inoculated with Bacillus amyloliquefaciens spores (108 spores/g) were packaged, preheated and then thermal or PATP-treated at various pressure (0.1, 500 MPa, 600 MPa and 700 MPa) and temperature combinations (95, 105, 110, and 121 C). The PATP resistance of B. amyloliquefaciens spores was lower than the thermal resistance at an equivalent process temperature. Further, an increase in process pressure or temperature also reduced the resistance of spores as indicated by the their associated lower D values. B. amyloliquefaciens spores were less sensitive to pressure changes at higher temperatures (zp = 332.2 MPa at 121 C) than at lower temperatures (zp =170.2 MPa at 95oC). Similarly, the temperature sensitivity of B. amyloliquefaciens spores was also different depending on the pressure level. While the spores were most sensitive to temperature changes at atmospheric pressure (zT = 8.2 C), the temperature sensitivity decreased with increasing pressures (zT = 16.7 C at 500 MPa and zT = 26.8 C at 700 MPa). Non-linear Weibull model parameters could be used as potential alternatives for D values to describe the influence of pressure or temperature on the PATP spore inactivation.