Bacteria-killing chemicals may be masking salmonella

WASHINGTON – The Agriculture Department is reviewing research that shows new bacteria-killing chemicals used in chicken slaughterhouses may be masking the presence of salmonella and other pathogens that remain on the meat that consumers buy, according to records and interviews.

Academic researchers agree that the chemicals could be overwhelming an antiquated testing process. Several of the scientists have been enlisted by the USDA’s food safety experts to help resolve the matter.

The issue came to the department’s attention this spring after chemical companies pointed to academic research that shows there could be a problem and told the USDA that further study was needed.

“This is a valid concern,” said Catherine Cutter, chairwoman of Penn State University’s Food Safety Impact Group, whose scientific work was referenced in materials chemical companies provided to the USDA.

The new controversy comes as the number and strength of chemicals used on poultry-processing lines is increasing to meet new USDA demands to slash pathogens.

Some experts say the rising tide of chemicals may be causing unanticipated side effects. Some USDA inspectors said they believe such chemicals can contribute to a host of medical problems, including respiratory ailments and persistent skin rashes. The Occupational Safety and Health Administration is conducting a follow-up investigation into a New York poultry plant where one inspector died after his lungs bled out in 2011.

The latest allegations — that the stronger chemicals are undermining testing — are spurring finger-pointing among rivals competing to sell their products to chicken processors. The companies say their competitors are the ones tripping up the tests.

At issue in the latest allegations is the testing procedure the USDA requires. As the chicken moves down the processing line, the bird is sprayed and bathed in an average of three to four different chemicals. To check that most bacteria have been killed, occasional test birds are pulled off the line and tossed into plastic bags filled with a solution that collects any remaining pathogens. That solution is sent to a lab for testing, which occurs about 24 hours later. Meanwhile, the bird is placed back on the line and ultimately packaged, shipped and sold.

Scientists say in order for tests to be accurate, it is critical that the pathogen-killing chemicals are quickly neutralized by the solution — something that routinely occurred with the older, weaker antibacterial chemicals. If the chemicals continue to kill bacteria, they indicate the birds are safer to eat than they actually are.

Several chemical companies — which all have a financial stake in the issue — were present at a June briefing on the matter with USDA officials. The department’s food safety experts asked for the briefing this spring, after the chemical companies raised concerns.

Jon Howarth, a scientist and vice president of Enviro Tech Chemical, who took part in the meeting, said some of the newer chemicals are not deactivated in the solution.

The company’s scientists put together a lengthy PowerPoint presentation that cited research from a USDA scientist and several university scientists that they believe backed up their assertions about the new chemicals. Over the past few years, poultry plants have cut salmonella rates in half, according to USDA test data.

The dramatic reduction in salmonella rates has raised suspicions about the tests among USDA inspectors, a union representative said. “I don’t really know if the new treatments are working or if it’s giving us all false hope,” said David Hosmer, president of the Southwest Council of Food Inspection Locals. Howarth, who was a main presenter at the briefing, said he believes the problem with the testing explains why the number of people getting sick from salmonella in poultry has not dropped in recent years even though test results have improved.

The chemical that came in for the greatest scrutiny at the USDA briefing meeting was cetylpryridinium chloride. Over the past three years, CPC has become the finishing rinse of choice in about 30 percent of poultry plants nationwide.

Enviro Tech recently posted a YouTube video showing a laboratory experiment that the company says proves CPC is not neutralized if not adequately rinsed when the test sample is taken and therefore produces false test results, sometimes called a “false negative” or “false kill.”

Besides CPC, other chemicals getting a closer look from USDA include formulas containing high levels of peracetic acid and acidified sodium chlorite. Their use has become commonplace over the past few years in nearly all U.S. poultry slaughterhouses, scientists and experts in the poultry chemical industry said.