Contents: Surveillance of foodborne disease | Phasing out ethylene oxide | Campylobacter in cattle and sheep | Campylobacter (and others) in the kitchen | The Food Safety ToolKit™
Surveillance of foodborne disease
In 2000, the Commonwealth Department of Health and Ageing established OzFoodNet to enhance surveillance of foodborne disease in this country.
The OzFoodNet network consists of epidemiologists specifically employed by each State and Territory health department to conduct investigations and applied research into foodborne disease.
OzFoodNet has recently published its second annual report (Communicable Diseases Intelligence 27 2003 210) which provides a number of interesting findings.
During 2002 there were 23,434 notifications of eight bacterial diseases. Of these, 14,716 cases were of campylobacteriosis and 7,917 were salmonellosis thus maintaining their positions as the two most frequently reported causes of foodborne illness in Australia.
Salmonella infections
The rate of Salmonella notifications in OzFoodNet sites ranges from 24.8 per 100,000 population in Victoria to 166.7 cases per 100,000 population in the Northern Territory. Notification rates for salmonellosis increased from south to north along the eastern seaboard of Australia. No explanation is advanced for these observations but the influence of ambient temperatures and food handling practices is an obvious candidate.
The highest rate of Salmonella infection on an age basis was 230.4 cases per 100,000 population in 0-4 year old males while notification rates were also elevated in the 5-9 age group in all areas under surveillance.
Campylobacter infections
Data for campylobacteriosis was not available for New South Wales where the infection is not notifiable. With this exception, OzFoodNet sites reported 14,716 cases of Campylobacter in 2002 highlighting the importance of this organism as a cause of enteric disease. Geographically, there was no trend in increasing or decreasing rates of notification of Campylobacter infection with latitude along the eastern seaboard in contrast to the pattern observed for Salmonella infections.
The highest age specific rates were in males in the 0-4 year age group emphasising the fact that young children are one of the at risk groups for enteric disease.
Listeria infections
Ninety-seven per cent (60/62) of Listeria infections during 2002 were reported in persons who were either elderly and/ or immunocompromised. The highest age specific rate of 1.5 cases per 100,000 population was in males over the age of 60. During 2002, OzFoodNet reviewed listeriosis notifications in Australia and identified that three out of five outbreaks in the years between 1995 and 2000 had occurred in hospital settings.
Agents involved in outbreaks
The most common bacterial agent responsible for foodborne disease outbreaks was Salmonella which caused 28 per cent (26/92) of outbreaks. A total of 543 persons were affected with a hospitalisation rate of 13 per cent (68/543). S. typhimurium was responsible for 81 per cent (21/26) of Salmonella outbreaks. Two fatalities were reported from two separate outbreaks of S. typhimurium.
There was one outbreak only of campylobacteriosis which affected 24 people and eight outbreaks due to Clostridium perfringens. Two of these were in aged care facilities where the effects of this usually mild disorder can be much more serious.
Conclusion The report notes that it is important that foodborne disease surveillance is able to assess whether food safety policies and campaigns are working. National surveillance of foodborne disease has many benefits and provides long-term data to assist with this task.
Food Science Australia
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