Inactivation kinetics and injury recovery of Bacillus amyloliquefaciens spores in low-acid foods during pressure-assisted thermal processing

Pressure-assisted thermal processing (PATP) inactivation kinetics of Bacillus amyloliquefaciens spores in deionized water (DIW) were evaluated for egg patty mince (EPM) and green pea puree (GPP). Recovery of PATP-injured spores during storage was determined. The number of B. amyloliquefaciens spores in DIW was reduced more than 6 log when treated at 121°C and 700 MPa, including a come-up time reduction (3.32 log MPN/g) and a pressure holding time reduction (3.55 log MPN/g). Treatments at 700 MPa in combination with 105°C for 16 min, 115°C for 5 min, or 121°C for 3 min, decreased B. amyloliquefaciens spore populations in EPM to levels undetectable using an enrichment procedure. No significant ( p >0.05) recovery of PATP-injured spores was observed in EPM and GPP during storage for 8 weeks, compared with controls. These results provide useful information for enhancing microbial lethality of PATP-resistant bacterial spores in low-acid foods.