Sweet solution to tainted poultry.

Sweet solution to tainted poultry

Sweetening the drinking water of broiler chickens with lactose -- or milk sugar -- dramatically increases their ability to fend off infection by Salmonella typhimurium, a new study shows. Researchers estimate that this bacterium, which produces few if any symptoms in infected chickens, taints 5 to 30 percent of the 5.5 billion broiler chickens raised annually in the United States. It also appears responsible for roughly one-quarter of U.S. Salmonella food poisonings.

At the Agriculture Department's Veterinary Toxicology Research Unit in College Station, Tex., John R. DeLoach and his co-workers have been inoculating 3-day-old broiler chicks with 100 million S. typhimurium bacteria apiece. One week later, they inspect the birds for signs of infection. So far, all birds raised on regular drinking water have become heavily infected but only 53 percent of those given water containing 2.5 percent lactose show signs of the microbe. Moreover, untreated birds harbor 99.9 percent more bacteria than the lactose-treated birds that became infected. An interim report on the first three double-blind lactose trials will appear this summer in AVIAN DISEASES.

While DeLoach isstill working to identify the mechanism behind the sugar's effect, his preliminary data do offer some hints. Lactose reduces the pH of a chicken's gut. DeLoach suspects the anaerobic bacteria fermenting this sugar produce short-chain fatty acids that can poison the Salmonella -- provided the bird's small intestine has been sufficiently acidified. Only one other sugar -- D-mannose, derived from a Mediterranean plant -- appears comparable to lactose in effect, but it costs roughly 20 times as much.