Pressure-Induced Germination and Inactivation of Bacillus cereus Spores and Their Survival in Fresh Blue Crab Meat (Callinectes sapidus) During Storage

Abstract

ABSTRACT Pressure-induced germination and inactivation of three strains of B. cereus spores by high hydrostatic pressures between 100 and 550 MPa at 40°C for 15 min was studied. In sterile distilled water, spore germination remained stable with pressures up to 300 MPa, and increased at pressures between 300 and 500 MPa, with maximum germination and inactivation obtained at 550 MPa. Of the 3 strains, spores from the crabmeat isolate were found to be the most resistant to germination and inactivation by pressure. In fresh crabmeat the B. cereus spores were more resistant to inactivation, but germination was improved compared to spores suspended in distilled water. Fresh crabmeat inoculated with B. cereus spores, treated with high pressure (550 MPa, 40°C, 15 min) and then stored at 4 and 12°C for 31 days showed that B. cereus was not a competitive organism in the presence of crabmeat microflora. Some pressure-sensitive microflora were inactivated in the treated crabmeat, but B. cereus survived through the end of the 4°C storage period.