Factors affecting the pressure resistance of some Campylobacter species.
OBJECTIVE
To compare pressure resistance between strains of Campylobacter jejuni, Campylobacter coli, Campylobacter lari and Campylobacter fetus, and to investigate the effect of suspending medium on pressure resistance of sensitive and more resistant strains.


RESULTS
Six strains of C. jejuni and four each of C. coli, C. lari and C. fetus were pressure treated for 10 min at 200 and 300 MPa. Individual strains varied widely in pressure resistance but there were no significant differences between the species C. jejuni, C. coli and C. lari. Campylobacter fetus was significantly more pressure sensitive than the other three species. The pressure resistance of C. jejuni cultures reached a maximum at 16-18 h on entry into stationary phase then declined to a minimum at 75 h before increasing once more. Milk was more baroprotective than water, broth or chicken slurry but did not prevent inactivation even of a resistant strain at 400 MPa.


CONCLUSIONS
Pressure resistance varies considerably between species of Campylobacter and among strains within a species, and survival after a pressure challenge will be markedly influenced by culture age and food matrix.


CONCLUSIONS
Despite the strain variation in pressure resistance and protective effects of food, Campylobacter sp. do not present a particular problem for pressure processing.
Martínez-Rodriguez
A
A
School of Food Biosciences, University of Reading, Reading, UK.
Mackey
B M
BM
D000818:Animals; D002167:Campylobacter / Q000145:classification* / Q000254:growth & development*; D017000:Campylobacter coli / Q000254:growth & development; D002168:Campylobacter fetus / Q000254:growth & development; D016123:Campylobacter jejuni / Q000254:growth & development; D044863:Campylobacter lari / Q000254:growth & development; D002645:Chickens / Q000382:microbiology; D015169:Colony Count, Microbial; D003470:Culture Media; D004203:Disinfection / Q000379:methods; D006874:Hydrostatic Pressure; D008892:Milk / Q000382:microbiology
D003470:Culture Media