A new study from the University of Veterinary Medicine in Vienna has shown that Campylobacter jejuni is protected and dependent upon the presence of spoilage bacteria on meat, in particular Pseudomonas for survival.
It is known that C. jejuni cannot grow under normal atmospheric conditions – the levels of oxygen are too high for it – so how it survives was until recently unknown. The mystery has now been solved by Friederike Hilbert and colleagues at the Institute of Meat Hygiene, Meat Technology and Food Science of the University of Veterinary Medicine, Vienna.
The surface of meat harbours a number of species of bacteria that – fortunately – are rarely harmful to humans, although they are associated with spoilage. It seems possible that the various species interact and Hilbert hypothesized that such interactions might help bacteria such as Campylobacter jejuni survive under hostile, oxygen-rich conditions. She thus tested the survival of C. jejuni in the presence of various meat-spoiling bacteria. When incubated alone or together with bacteria such as Proteus mirabilis or Enterococcus faecalis, Campylobacter survived atmospheric oxygen levels for no longer than 18 hours. However, when incubated together with various strains of Pseudomonas, Campylobacter were found to survive for much longer, in some cases over 48 hours, which would be easily long enough to cause infection.
Campylobacter jejuni is a bacterium found primarily in the intestinal gut of animals and birds and shed primarily through the feces. Poultry feces have been found to contain up to 106 cells or more per gram. The infective dose for campylobacteriosis (disease acquired from the bacterium) can be as low as 500 cells. This makes it very easy for people to get sick from food contaminated with Campylobacter jejuni. Symptoms commonly associated with campylobacteriosis are enteric in nature, that is abdominal cramps, diarrhea, in some cases bloody diarrhea, nausea, and vomiting. Keep poop away from food.
Friederike Hilbert, Manuela Scherwitzel, Peter Paulsen and Michael P. Szostak. Survival of Campylobacter jejuni under Conditions of Atmospheric Oxygen Tension with the Support of Pseudomonas spp.
September issue of the Journal Applied and Environmental Microbiology (Vol. 76, 5911-5917).