The bacterium campylobacter, which causes the majority of food poisoning cases in Ireland, but which remains somewhat mysterious in its characteristics and transmission, has just become the subject of a major investigation.
Dr Paul Whyte, senior research associate in UCD's veterinary lab, says: "There's very little information available at present because of the relatively mild symptoms. An individual may be debilitated for a few days and may not seek any medical attention so there is a lot of under-reporting."
The project, which is funded by the Food Safety Promotion Board, will study campylobacter specimens from the Eastern Health Board region, the Western Health Board and the Belfast area. As well as these samples from patients, researchers from QUB, NUI Galway and UCD will examine samples of foods and water as well as swabbing pets.
"We hope to find out to what extent food can be associated with campylobateriosis in humans." The project started last month and will run for three years.
Meanwhile, researchers at NUI Galway recently developed a rapid test to identify camplyobacter jejuni which, as well as causing the usual diarrhoea, nausea and cramps, has been associated with a rare neurological condition known as Guillain-Barre syndrome.
The jury is still out on how humans contract campylobacteriosis, says Dr Wayne Anderson, the chief specialist (food science) with the Food Safety Authority of Ireland (FSAI). Some people believe it's an illness brought into our homes by our pets. Others associate it with pork and poultry. Both routes may well be relevant.
It is not a notifiable disease, in other words it is not mandatory to report it in the Republic, but a study carried out by the National Disease Surveillance Centre (NDSC) found there were more than 2,000 cases of laboratory-confirmed campylobacter enteritis in 1999. More than one quarter of these cases occurred in children under five years of age, with the highest number of cases in the seven to 12 months bracket.
Dr Thomas Quigley, chief consultant in food safety with the Food Safety Promotion Board, says the high incidence among under fives, those in their mid-20s and those in their mid-60s, seems to indicate that some sort of immunity is conferred after an infection.
There is also a seasonal pattern, with cases peaking in summer. For instance, in the Eastern Health Board region which had the highest number of cases, there were 27 cases in December, 38 in January, and 35 in February, with 80 in May, 69 in June and 69 in July.
Sunshine and higher temperatures mean barbecues, food left at room temperature or higher, food left out in the open, and food left in the car on the journey home from the supermarket, all increasing the chances of bacteria multiplying.
The number of reported cases of campylobacter food poisoning is an underestimate of the real incidence of disease. However the data reveals an incidence rate of 57.5 cases per 100,000 people, making it the single biggest cause of bacterial food poisoning in Ireland.
This compares with a rate of 51 per 100,000 in Northern Ireland, 104.9 in England and 116 in Scotland. In the Republic, there was a large regional variation with the North Eastern Health Board reporting the lowest incidence at 24.2 cases per 100,000 people and the Western Health Board having the highest rate at 110.7 cases per 100,000.
In some countries outbreaks have been associated with water and consumption of unpasteurised milk. Pasteurisation kills campylobacter.
The NDSC notes that further work is needed in the Republic to identify risk factors for those most at risk and to examine the reasons for the regional variation in incidence.
Campylobacter is very difficult to eliminate. The food industry is working to reduce contamination by both campylobacter and salmonella, but such measures are very expensive and will put a premium on food, says Dr Anderson.
"For years the poultry industry has been tracing salmonella and reducing numbers. But it's only now it is starting to try and reduce numbers of camplyobacter. It will be a few years before we see a decrease in contamination."
One study involves Superquinn, in association with egg producers Carton Brothers and NUI Galway. Begun in 1998, work is ongoing and is focused primarily on the poultry processing plant. European studies indicate flocks become infected with campylobacter from environmental sources. British, Danish and Swedish studies have demonstrated that, using strict hygiene barriers, levels of campylobacter can be reduced. These controls are currently being studied by NUI Galway.
For the present, the consumer should make the assumption that any raw poultry or pork - whether conventionally reared, organic or free range - contains the organism. Prevention is quite simple, according to Dr Anderson. Proper storage of meats, the prevention of crosscontamination and proper cooking are essential.
"If you have a young child at home you may wish to go the extra mile," he says. Consumers can use vacuum bags or boxes to keep meats cool on the journey home from the supermarket. Make sure the fridge is below 5 degrees centigrade Some washing-up liquids are anti-bacterial while some plastic chopping boards are impregnated with anti-bacterial agents.
Use separate chopping boards for raw and cooked meats, he suggests. "I don't buy into the `too much sterility around the home can damage your child's immunity' theory. We don't have the infant mortality rate we had in the past and a certain amount of that is due to good hygiene practices," adds Dr Anderson.
Food should be cooked adequately. Those with young children or elderly relatives at home might consider buying T sticks which change colour at 75 degrees centigrade or using a meat thermometer, he advises.
A study published in Which? magazine last month found 16 per cent of poultry from five supermarkets was contaminated with salmonella or campylobacter. The FSAI has done a survey of raw and cooked chicken meat, imported and homegrown, and results are expected in the next few months. More than 3,000 samples have been examined.
If dining out, consumers are advised that if they are not happy with the standard of food hygiene, they should report the premises to their local environmental health officer or contact the Food Safety Authority at 1890 33 6677. "Good food safety standards are your right, not a privilege," says Martin Higgins, chief executive of the Food Safety Promotion Board.