Campylobacteriosis in New Zealand: a new twist to the tale? Part one (the pathogen and the poultry plant).

摘要

New Zealand has a much higher rate of reported campylobacteriosis cases than the rest of the developed world. The main objectives of this study were first to explore the entire hypothesis in order to discover the causes of New Zealand's high rate of campylobacteriosis, and then to advise about the possible best remedies and interventions which could reduce the high rate in New Zealand. It has been assumed that New Zealand Campylobacter jejuni strains have either greater heat tolerance and thus are better able to survive cooking or that New Zealand has more oxygen tolerant strains. The other hypothesis suggested is: whether secondary processing practices may increase the contamination level of New Zealand chicken. The investigation revealed that New Zealand strains are not more heat resistant than other strains. Similarly the results did not indicate that the New Zealand strains differ in oxygen tolerance from most of the other internationally reported strains. The results also revealed that the secondary practice (marination by needle injection) investigated at a poultry plant does not significantly increase the contamination level of the carcasses. The QMRA study which used the Bayesian approach, has indicated that the increase in the probability that a bird in a poultry farm has been contaminated with Campylobacter or is positive for the pathogen has significant impact on the possible increase in the contamination prevalence of the slaughtered carcass. This is due to the transportation of the flock and the slaughtering process and leads to an increase in the total probability of illness. A strategy announced in 2006 expected a 50% reduction in the rate of notified campylobacteriosis cases over the next five year period. However, unexpectedly the reduction in the number of cases was 20% and 50% in 2007 and 2008 respectively. This reduction is questionable as it occurred in a very short time and this has raised questions for the scientific community in both New Zealand and abroad