Foodborne illness

While Australia has one of the safest food supplies in the world, the incidence of foodborne illness has been on the increase.  Assessing the frequency and impact of foodborne illness in any community is a difficult and complex task.  Historically, a lack of a nationally coordinated system and inconsistencies in State Regulatory procedures made it near impossible to generate accurate statistics.

Since 1999 the Australia New Zealand Food Standards Council agreed to an Australian Government proposal to coordinate "a collaborative program of work on food safety in order to ascertain and minimize the incidence and impact of foodborne illness in Australia".

One major outcome has been improved, State and National food poisoning notification schemes and the establishment of OzFoodNet in 2000.  The annual report of the OzFoodNet network for 2005 estimates that some 5.4 million cases of foodborne disease occur annually in Australia. Approximately 18,000 hospitalizations and 120 deaths occur annually.

The costs to the community are estimated at $1.2 billion dollars.

OzFoodNet and partner agencies coordinate the monitoring and investigation of diseases caused by the following key enteric pathogens:

• Campylobacter
• Salmonella
• Shigella
• Typhoid
• Shiga toxin producing E.coli and haemolytic uraemic syndrome
• Listeria
• Yersinia

The majority of foodborne disease is of a mild nature and goes largely unreported.  Thus most cases do not appear in surveillance statistics.  Broad community statistics are usually determined by extrapolation from studies which indicate the rates for under-reporting. It is believed that less than 10% of foodborne illnesses are reported.

The causes for the increase in foodborne disease have been the subject of some research and speculation.  Several factors are believed to have influenced the increase in the number of illnesses.

• Enhanced surveillance systems.
• Recognition of new and emerging pathogens previously not thought to be enteric pathogens.
• Improved diagnosis and food testing technologies.
• Community changes to food consumption patterns.
• Cultural shifts resulting in a reduction in consumer knowledge of food preparation and food hygiene practices.

The US National Academy of Sciences has estimated that in the past 20 years the list of known foodborne pathogens has tripled. It is likely that we have yet to discover all the known causes of food borne illness.

Persistent adverse consequences of gastroenteritis

A generally under-reported consequence of food poisoning is "Sequelae" from foodborne gastroenteritis.  Sequelae refers to all the illnesses that occur subsequently as a consequence of an acute intestinal infection.  These illnesses can persist for prolonged periods long after the bout of gastroenteritis.

The most significant of these, in statistical terms, are reactive arthritis and irritable bowel syndrome.  Somewhat rarer are the haemolytic uraemic syndrome and the Guillain-Barre syndrome.  Recent estimates suggest that in excess of 40,000 cases per annum of sequelae occur within our community with significant medical and consequential costs.

It is an area of continuing research and assessment by health authorities.

Principle causes of foodborne illness

The primary causes of foodborne illness are naturally occurring pathogenic bacteria, viruses, toxins and poisons. Some of these microbes infect our bodies and grow, while others produce a toxin in food. The end result is illness and in very severe cases may even cause death.

Some 200 different varieties of illness may be transmitted by food. By far the largest proportion of foodborne illness is the consequence of micro-organisms.  Food poisoning is generally accepted as being an essentially preventable illness brought on by our poor management of food preparation and food hygiene principles.  Human behaviour is the culprit.  A recent study funded by the Commonwealth Government and the NSW Government established an epidemiological profile of foodborne disease risks.  The key contributing factors to food poisoning outbreaks are listed below in order of significance.

• Inappropriate storage (food stored too long or too warm)    (29.0%)
• Food handlers contamination (poor hygiene)                      (14.5%)
• Inadequate cooking or reheating                                     (14.1%)
• Cross-contamination                                                     (14.1%)
• Foods from an unsafe source                                          (14.1%)

The order of these contributing factors can vary slightly from study to study, however the same top five factors consistently occur. The majority of food poisoning outbreaks are found to have two or more contributing factors associated with human activities all of which could be remedied.

Further information:

OzFoodNet Annual Reports - Foodborne disease

Communicable Diseases Australia- National Notifiable Diseases Surveillance   System (NNDSS)

Victorian Government Health Information - Consumer Research