COLLEGE STATION Two studies at Texas A&M University are aimed at keeping salmonella and campylobacter, the leading food-borne pathogens in the United States, from fouling up poultry at processing plants.
The first in broiler chickens indicates that simply adding a prophylactic such as lactic acid to poultry drinking water during the feed withdrawal period before slaughter will decrease the chances of contaminating carcasses with salmonella and campylobacter.
According to Dr. Dave Caldwell, assistant professor and one of the cooperating researchers on the project, the lactic acid acidifies the crop, a food storage area in the bird and reduces the risk of contamination.
“We think we’re on the right track,” Caldwell said of the cooperative research project with Dr. Billy Hargis, professor of veterinary medicine and pathobiology at Texas A&M, and Dr. Allen Byrd, research microbiologist with the U.S. Department of Agriculture-Agricultural Research Service in College Station.
Poultry, particularly broiler chickens, are “genetically selected essentially to consume feed,” Caldwell said. Just prior to slaughter, adult birds have to go through an 8-12 hour withdrawal from feed so that the intestinal tract will be clean from feed and other ingested materials.
“If the intestine ruptures without such a feed withdrawal period, then you have a dirty carcass that will not pass inspection,” he said.
But because broilers are bred to consume feed, birds will consume anything they can find in the chicken house, even if it is fecal matter from the floor. That ends up in the crop, which is part of the alimentary canal.
If, during the slaughtering process, the crop ruptures, it can contaminate that and other carcasses and the equipment around it with either salmonella or campylobacter.
This is disastrous from the standpoint of preventing the spread of food-borne pathogens in poultry,” Caldwell said.
Therefore, the practice that is intended to prevent food-borne illness actually amplifies a mechanism for the spread of salmonella and campylobacter.
“Our goal is to prevent the crop from becoming contaminated in the first place,” he explained.
The lactic acid is easily administered through the drinking water and is easily and inexpensively administered at the farm, Caldwell said.
“It is a very simple procedure, and it doesn’t cost the grower anything in terms of equipment, just the lactic acid,” he added.
In the second project, researchers looked at ways to reduce food-borne pathogen contamination in turkeys. The commercial processing plant for turkeys is different than that for broilers, Caldwell said. With chickens, contamination happens more frequently toward the end of the processing “line” at the site of crop removal. With turkeys, the processing is less automated, and the crops are removed by hand, making it less likely contaminated crops will rupture and subsequently foul up processed carcasses.
In both chickens and turkeys, carcasses are lowered into scalding water for 45 seconds to 1-1/2 minutes to facilitate feather removal. Texas A&M researchers found that increasing the temperature of the water and changing the pH could potentially lower the incidence of salmonella and campylobacter on processed turkeys, making this another inexpensive and easily-implemented process.
“Heat kills both salmonella and campylobacter very nicely,” Caldwell said.
The poultry industry seems very responsive to both procedures, he noted. One chicken processing complex in Mississippi has already begun using lactic acid on all of its farms.
Even with these preventative measures being implemented in processing plant, Caldwell said, the best way to eliminate the chance of contracting human food-borne illness by consuming poultry or other meat products lies in proper food handling and preparation.
“Poultry should be handled appropriately and cautiously and cooked well,” he said.
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