Comparison of Pulse Light Resistance in the Spores of Different Alicyclobacillus acidoterrestris Strains

Abstract

　In the present study, we compared the resistance of the spores of Alicyclobacillus acidoterrestris strains NBRC 106287, NBRC 106295, and NBRC 108913 to pulse light (PL) treatment (light intensity 73±3 mJ/cm²/pulse) in a citrate buffer solution. The number of spores surviving after the PL treatment differed among the strains because of differences in the formation of spore-vegetative cell aggregates during spore preparation. However, these differences were eliminated after the aggregates were dispersed by sonication, and the spore concentrations of all strains were reduced to below the detection limit after three irradiations. These results suggested that there is no difference in the PL resistance of the investigated strains of A. acidoterrestris ; however, the formation of spore-vegetative cell aggregates is an important factor that needs to be controlled in the PL treatment.