High pressure homogenization (HPH) has been proposed as an effective alternative to high hydrostaticpressure in the continuous sanitization of fluid food systems. In this study, we evaluated the influenceof HPH treatment, applied individually (one, two or three cycles) or in combination with other mild physicalor chemical stresses (mild heat treatment H2O2 and low pH), on the capability of Bacillus cereus andBacillus subtilis spore, suspended in sterilized double distilled water, to form colonies. Although platecount only slightly decreased in all the strains when one cycle of HPH at 150 MPa was applied alone,the spores released significant levels of dipicolinic acid (up to 28%) that could indicate a possible disruptionof spore layers. Three consecutive cycles of HPH determined high reduction of colony count (about5logCFU/ml) and high DPA release (52%). Among the stress conditions applied, it was observed that onlythe thermal shock after one HPH cycle reduced the colony count of 2.3 logCFU/ml and induced a DPArelease up to 57%.These results suggested HPH as a novel application for B. cereus and B. subtilis control in fluid foods.[...]
Effect of high pressure homogenization applied individually or in combination with other mild physical or chemical stresses on Bacillus cereus and Bacillus subtilis spore viability
CHAVES LOPEZ, CLEMENCIA;SERIO, ANNALISA;PAPARELLA, Antonello;SUZZI, Giovanna
2009-01-01
Abstract
High pressure homogenization (HPH) has been proposed as an effective alternative to high hydrostaticpressure in the continuous sanitization of fluid food systems. In this study, we evaluated the influenceof HPH treatment, applied individually (one, two or three cycles) or in combination with other mild physicalor chemical stresses (mild heat treatment H2O2 and low pH), on the capability of Bacillus cereus andBacillus subtilis spore, suspended in sterilized double distilled water, to form colonies. Although platecount only slightly decreased in all the strains when one cycle of HPH at 150 MPa was applied alone,the spores released significant levels of dipicolinic acid (up to 28%) that could indicate a possible disruptionof spore layers. Three consecutive cycles of HPH determined high reduction of colony count (about5logCFU/ml) and high DPA release (52%). Among the stress conditions applied, it was observed that onlythe thermal shock after one HPH cycle reduced the colony count of 2.3 logCFU/ml and induced a DPArelease up to 57%.These results suggested HPH as a novel application for B. cereus and B. subtilis control in fluid foods.[...]I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
