THE number of cases of food poisoning could be dramatically cut now that US government researchers have developed the first simple test for the bacterium Campylobacter. In another breakthrough, scientists have developed a scanner that can reveal whether cattle carcasses are contaminated with faeces that could cause disease.
Every year, millions of people in the industrialised world come down with food poisoning caused by Campylobacter. It affects four times the number of people stricken by the better-known Salmonella. Yet until now, there has been no quick or reliable test for Campylobacter in livestock or food.
"Campylobacter has not had the attention of other food-poisoning bacteria," says Irene Wesley of the National Animal Disease Center (NADC) in Ames, Iowa. "It is hard to grow in the lab, and while it makes more people sick than, say, Salmonella, it kills less frequently." However, Campylobacter is thought to cause between 20 and 40 per cent of cases of Guillain-Barr? syndrome, a severe neural disorder that can make people so weak they may need help breathing.
Until now, diagnosing Campylobacter infections or identifying the bacterium in food involved weeks of culturing, and the methods used to distinguish the most dangerous species were unreliable. But Wesley and her colleagues have solved both problems with a test that uses the polymerase chain reaction to amplify Campylobacter's DNA. The test takes only eight hours to complete and can reliably identify the worst culprit, C. jejuni, as well as several other species.
The first trials of the test have revealed that 39 per cent of healthy dairy cattle in the US carry C. jejuni in their faeces, which can contaminate milk and carcasses at slaughter. It is also present in the faeces of up to 70 per cent of healthy adult pigs and 90 per cent of piglets.