The development of Escherichia coli and Listeria monocytogenes variants resistant to high-pressure carbon dioxide inactivation.
OBJECTIVE
The objective of this study was to investigate whether bacterial cells could develop resistance (as a part of their adaptation strategy) to high-pressure CO(2) (HPCD) inactivation.


RESULTS
Alternating cycles of exposure to pressurized CO(2) (10.5 MPa, 35 degrees C, 400 min(-1), 70% working volume ratio during 10 min) and re-growth of the surviving subpopulation were used to investigate possible increases in the resistance of Escherichia coli and Listeria monocytogenes to HPCD. The results show an increased resistance of both pathogens tested after seven cycles of inactivation. Increase in the resistance after 15 cycles resulted in a difference of 2.4 log CFU ml(-1) in log N(0)/N(i) when parental (N(0)) and treated cultures (N(i)) of E. coli and L. monocytogenes were compared.


CONCLUSIONS
Current findings indicate the ability of micro-organisms to adapt to HPCD preservation technology.


CONCLUSIONS
The occurrence of HPCD-resistant micro-organisms could pose a new hazard to the safety and stability of HPCD-processed foods.
Garcia-Gonzalez
L
L
Business Unit Separation and Conversion Technology, Flemish Institute for Technological Research (VITO), Mol, Belgium.
Rajkovic
A
A
Geeraerd
A H
AH
Elst
K
K
Van Ginneken
L
L
Van Impe
J F
JF
Devlieghere
F
F
D002245:Carbon Dioxide / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000502:physiology*; D005516:Food Microbiology; D005519:Food Preservation; D008089:Listeria monocytogenes / Q000187:drug effects / Q000502:physiology*; D050296:Microbial Viability / Q000187:drug effects; D011312:Pressure
D002245:Carbon Dioxide