The response of Campylobacter jejuni to low temperature differs from that of Escherichia coli.
Human infection with Campylobacter jejuni is often associated with the consumption of foods that have been exposed to both chilling and high temperatures. Despite the public health importance of this pathogen, little is known about the effects of cold exposure on its ability to survive a subsequent heat challenge. This work examined the effect of rapid exposure to chilling, as would occur in poultry processing, on the heat resistance at 56 degrees C of two C. jejuni strains, 11168 and 2097e48, and of Escherichia coli K-12. Unlike E. coli K-12, whose cold-exposed cells showed increased sensitivity to 56 degrees C, such exposure had only a marginal effect on subsequent heat resistance in C. jejuni. This may be explained by the finding that during rapid chilling, unlike E. coli cells, C. jejuni cells are unable to alter their fatty acid composition and do not adapt to cold exposure. However, their unaltered fatty acid composition is more suited to survival when cells are exposed to high temperatures. This hypothesis is supported by the fact that in C. jejuni, the ratio of unsaturated to saturated fatty acids was not significantly different after cold exposure, but it was in E. coli. The low-temperature response of C. jejuni is very different from that of other food-borne pathogens, and this may contribute to its tolerance to further heat stresses.
Hughes
Rebecca-Ayme
RA
Division of Veterinary Pathology, Infection and Immunity, School of Clinical Veterinary Science, University of Bristol, Langford, Bristol BS40 5DU, United Kingdom. Rebecca.Hughes@bristol.ac.uk
Hallett
Kathy
K
Cogan
Tristan
T
Enser
Mike
M
Humphrey
Tom
T
D016123:Campylobacter jejuni / Q000737:chemistry / Q000502:physiology* / Q000528:radiation effects*; D003080:Cold Temperature; D015169:Colony Count, Microbial; D048168:Escherichia coli K12 / Q000737:chemistry / Q000502:physiology* / Q000528:radiation effects*; D005227:Fatty Acids / Q000032:analysis; D006358:Hot Temperature; D006801:Humans; D050296:Microbial Viability / Q000528:radiation effects; D013312:Stress, Physiological
D005227:Fatty Acids