Plant Sanitation a Problem? Check for Overstressed Turkeys - By The Food Safety Consortium - This article is taken from Mays issue of the FSC's Newsletter and looks at the effect sanitary conditions have on the stress levels of turkeys.

Gerry Huff, a USDA-ARS microbiologist at the University of Arkansas, examines vials containing biofilm from turkey synovial cultures. She is trying to demonstrate that the cultures, from turkeys’ knees, contains Listeria monocytogenes.

The floors, the drains and the overall environment in a typical poultry processing plant can easily be a natural source for growing the pathogenic bacterium Listeria monocytogenes, which can then contaminate the poultry going down the processing line. The pathogen’s natural occurrence in the environment is reason enough for the industry’s emphasis on sanitation.

There may be another possible source of contamination in some of the turkeys on the processing line: the turkeys themselves. That’s because of the stress levels that a small fraction of them aren’t able to tolerate. A result of opportunistic bacterial infection is turkey osteomyelitis complex (TOC), a stress-related disease that strikes male turkeys. The effect of stress can weaken the turkeys’ immune system and make them susceptible to infection by pathogens.

“It’s a condition of processing turkeys that occurs at an average incidence of 0.2 percent of all processed turkeys,” said Gerry Huff, a U.S. Department of Agriculture microbiologist who is researching the issue for the Food Safety Consortium at the University of Arkansas. But even just 0.2 percent still adds up to a long line of turkeys that could be bringing disease into plants on their own. One infected turkey can contaminate the processing plant’s surface.

Huff ’s project has determined that infections of some turkeys’ joints, bones and soft tissues may be a contributing factor of contamination in plants and that Listeria monocytogenes may be an opportunistic pathogen that strikes the turkey’s respiratory system. Listeria monocytogenes, if contracted by a human consuming an infected turkey, can kill infants, the elderly, pregnant women and immunocompromised individuals.

“The stress response is different in males, especially as they approach adolescence and they encounter all of the social pressures of maintaining their pecking order,” Huff said. So her task is to find ways to improve conditions, to efficiently produce the turkeys without as much stress in the environment and to counteract stress through nutrition.

“You’ll have some turkeys who react to the changes and stresses that they encounter by increasing corticosteroids (steroid hormones) to a level that instead of going up and coming back down, the level just stays up there,” Huff explained. “So with every little stress they counter, they keep increasing their levels of natural corticosteroids to such an extent that it inhibits their immune response.”

The turkeys breathe bacteria from their flocks’ environment into their respiratory systems, with infection by E. coli being the top respiratory disease. Huff ’s research group wants to find out if Listeria monocytogenes is infecting the turkeys as a more chronic disease even though it occurs at a much lower frequency than E. coli infections.

“It’s interesting that the respiratory route has not been looked at as a model for listeriosis infection,” Huff said. “But the respiratory route is the most important disease route in poultry.” “It’s not acute, and it’s not killing birds,” Huff said of listeriosis. “But they may get chronically infected, and then perhaps they can sequester the organisms in their joints. That’s the program in a nutshell.

Source: The Food Safety Consortium Newsletter - May 2004