A new technique significantly reduces salmonella in chickens by providing protection that, before factory farming, was naturally transferred from a mother hen to her chicks, scientists announced Thursday.
The product, called CF-3 or Preempt, a mixture of beneficial microbes that occur naturally in chicken, was approved last week by the Food and Drug Administration.
“This is a major milestone for food safety,” Agriculture Secretary Dan Glickman said in a National Press Club speech.
Officials estimated the treatment would add 2 cents a pound to the retail price of chicken.
If the technique proves successful, it also could reduce the use of antibiotics in chicken, a practice that scientists say has contributed to an increase in drug-resistant bacteria.
Critics of the poultry industry were unusually optimistic about Preempt because it is one of the few tools at the farm level that reduces disease-causing bacteria. But Preempt will not completely eliminate salmonella, which means there still will be opportunities for reinfection though at lower levels.
“Any level of salmonella on a bird is a problem,” said Caroline Smith de Waal, director of food safety for the Center for Science in the Public Interest, a Washington-based consumer advocacy group. “But if we can get numbers lower and lower eventually more birds will be coming out of the processing plant salmonella-free. The hurdle will be getting the industry to use it.”
Salmonella is one of the leading causes of food-borne illness and about 20 percent of chickens are infected with it. Incidents of foodborne illnesses are difficult to track and often go unreported, but public health officials estimate that there are between 800,000 and 4 million cases of salmonellosis a year in the United States and 960 to 1,920 deaths.
Preempt also may prove beneficial in reducing or eliminating other disease-causing bacteria. There is preliminary evidence that Preempt helps protect chickens against campylobacter, which is far more prevalent in chickens than salmonella and is responsible for many more illnesses.
Preempt, developed by Agriculture Department scientists and MS BioScience, a division of Milk Specialities Co. of Dundee, Ill., involves spraying newly hatched chicks with a solution that contains 29 beneficial bacteria. The birds peck their wet feathers and ingest the bacteria, which begin to grow inside the chicks’ intestines. Any salmonella ingested later cannot compete with the “good bacteria” and thus passes harmlessly through the intestines.
“What we are doing essentially is replacing the mother hen,” said Dr. John DeLoach, one of the developers of Preempt and now general manager of MS BioScience. Before there were factory farms, a hen passed her resistance to salmonella to her chicks through her fecal droppings. In factory farming, the breeder hens do not stay with the chicks.
Dr. Michael Osterholm, the state epidemiologist for the Minnesota Health Department, and a proponent of irradiation, a controversial technique to eliminate disease-causing bacteria from food, is less sanguine than others about the value of the process.
“One of the major sources of salmonella contamination is in the processing plants, like the chill baths, which one processor called bacterial soup, so even if there is a lesser amount of salmonella going in there is no reason to believe there will be a lesser amount coming out.”
In tests involving 80,000 chickens, the Preempt spray reduced salmonella from about seven percent in untreated chickens zero percent in the intestines of the treated chickens. But salmonella was still detected in the chicken houses. And there have been no studies of salmonella levels in chickens treated with Preempt after they have been processed.
Keith Rinehart, the vice president for technical services at Perdue, said that the company had tried similar products in the past but that they had not proven useful in reducing salmonella levels. “The ones we’ve looked at didn’t make that much difference by the time the chickens were ready to be processed. We are hopeful that this one is more effective. But it is definitely not a panacea because it will not take salmonella down to zero.”
Dr. Donald Corrier, a veterinary pathologist for the Department of Agriculture and the project leader for Preempt, cautions that even though the product can reduce contamination “to produce a cleaner chicken there is a need for an integrated program that carries all the way through the process from farm to store. For Preempt to be beneficial requires cooperation in all parts of the industry.” Proper sanitation from farm to supermarket is still essential.