Washington D.C.—A team of researchers, led by scientists from USDA’s Agricultural Research Service, has published the results of a study suggesting that antimicrobial sprays and dips applied to chicken “may create false negative results” in Salmonella testing. The study substantiates earlier claims that certain chemicals, in particular cetylpyridinium chloride (CPC), remain in high enough quantities on chicken carcasses to contaminate testing samples. The authors conclude that the USDA Food Safety and Inspection Service’s (FSIS) testing procedures for Salmonella on poultry “may need modification.”
“This research calls into question the FSIS data on Salmonella contamination in chicken,” said Thomas Gremillion, Director of Food Policy at Consumer Federation of America. “FSIS has reported significant reductions in positive test samples every year for the last several years, but this study suggests those numbers might reflect flaws in the testing procedures rather than actual gains towards protecting consumers.”
FSIS testing procedures have changed little in recent years, even as the agency has advised poultry processors to employ more chemical interventions. To test for Salmonella, a technician pulls a poultry carcass from the “chiller” at the end of the slaughter line. The technician puts the carcass into a sample bag filled with a buffered peptone solution, and then removes the carcass and sends the solution to the lab for testing. When USDA established this procedure in 1998, companies applied chemical interventions like chlorine earlier in the slaughter process. The solutions in the chillers would wash off and dilute the anti-microbial agents, and the buffered peptone solution would neutralize any remaining chemicals. Now, however, processors apply antimicrobial agents later in the process, including post-chill antimicrobial dips and sprays.
In 2013, researchers affiliated with the University of Georgia and Enviro Tech Chemical, one of the leading manufacturers of peracetic acid, delivered a presentation to FSIS suggesting that antimicrobials may create false negatives when used in accordance with FSIS procedures. According to the researchers, USDA significantly underestimates contamination in poultry as a result of testing flaws. They recommended that the agency confirm their results, and prescribe in detail how establishments should neutralize chemical interventions.
This latest study appears to provide the requested confirmation. When, or whether, FSIS will modify its testing procedures remains an open question.
“Over the last three years, we have repeatedly asked FSIS officials what the agency is doing to address carryover of these antimicrobials into testing samples,” said Wenonah Hauter of Food and Water Watch. “They have told us that they are working to develop a new neutralizing agent, but in the meantime, how are we supposed to interpret these test results? FSIS should modify its testing procedures now to avoid false negatives.”
FSIS tests thousands of poultry samples for Salmonella each year and uses the results to determine whether poultry plants are meeting recommended performance standards. Under the agency’s Salmonella Initiative Program, some poultry plants receive waivers from normal inspection requirements if test results indicates a low incidence of Salmonella. Test results also served as a frequently cited rationale for the agency’s controversial New Poultry Inspection System rule, which replaces government inspectors with company employees.
The Safe Food Coalition is made up of consumer groups, public health groups, groups representing victims of foodborne illness, and labor organizations dedicated to reducing the burden of foodborne illness in the United States by improving government food inspection programs.
Safe Food Coalition members include:
- Center for Foodborne Illness, Research and Prevention, Patricia Buck, 724-992-1969
- Center for Science in the Public Interest, David Plunkett, 202-332-9110
- Consumer Federation of America, Thomas Gremillion, 202-939-1010
- Consumers Union, William Wallace, 202-462-6262
- Food & Water Watch, Tony Corbo, 202-683-2449
- National Consumers League, Sally Greenberg, 202-835-3323
- STOP Foodborne Illness, Deirdre Schlunegger, 773-269-6555
- Government Accountability Project, Amanda Hitt, 202-457-0034