Effects of moderately high pressure plus heat on the germination and inactivation of Bacillus cereus spores lacking proteins involved in germination.

AIMS

To determine the germination and inactivation of Bacillus cereus spores lacking various germination proteins using moderately high pressure (MHP) and heat.

METHODS

The inactivation and germination of wild-type B. cereus spores in buffer by MHP (150 MPa) at various temperatures, as well as the MHP inactivation and germination of B. cereus spores lacking individual germinant receptors and monovalent cation antiporters, was determined.

RESULTS

Loss of individual germinant receptors had no large effects on spore inactivation or germination, although germination of receptor-deficient spores was generally slightly decreased. Loss of the GerN in particular the GerN and GerT antiporters also decreased spore germination by MHP, especially at 40 and 50 degrees C.

CONCLUSIONS

Both inactivation and germination of B. cereus spores by MHP increased with rise of temperature; however, mutant strains lacking individual germinant receptor had similar levels of germination as compared to wild-type spores. To evaluate the role of germinant receptors in MHP, a strain lacking a large number of germinant receptors is needed.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this work may lead to a better understanding of how MHP causes germination of spores of B. cereus.