Flies sucked through ventilation shafts into industrial chicken coops may be the primary carriers of a major cause of food poisoning in people, a Danish study suggests.
Campylobacter bacteria, such as the common Campylobacter jejuni, plague even the cleanest of chicken farms. Nearly half of Danish broiler chickens acquire the bacteria during their 6-week lives. In U.S. flocks, the infection rate is greater than 80 percent.
"Once a chicken gets infected, [campylobacter] spreads very rapidly throughout the whole broiler house," says Karl Pedersen of the Danish Institute for Food and Veterinary Research in Århus. The bacteria don't harm the chickens but can cause diarrhea in consumers who eat undercooked chicken. Other raw meats, unpasteurized milk, and contaminated water can also transmit the bacteria to people.
Chicken flocks raised during the summer face the greatest risk of campylobacter infection—a seasonal pattern that had lacked explanation.