A new study by researchers of Johns Hopkins Bloomberg School of Public Health reveals that poultry carriers not only roll out a powerful odor, they also apparently trail an airborne plume of potentially harmful bacteria. Human exposure to antibiotic-resistant bacteria requires changing transport methods in areas of intense poultry production.

The researchers - Ana Rule, Ellen Silbergeld and Sean Evans - trailed two or three car lengths behind a chicken truck for 17 miles along the Delmarva Peninsula. They turned off the air conditioners and opened the windows to get a good dose of the vehicle's slipstream. They found increased concentration of bacteria in air samples collected from inside the car and on surfaces in the car, such as the door handle.

However, researchers don't know how much of a hazard the levels found suggest; as Rule said: "We don't know what's normal. ... All we know is the levels are higher." She added that further research is needed to gauge the risk.

About 20 percent of the bacteria were resistant to the antibiotics tetracycline, erythromycin and quinupristin/dalfopristin. Since these drugs are all approved for use in broiler chickens, researchers say it suggests that giving chickens antibiotics leads to antibiotic-resistant bacteria.

The National Chicken Council has issued a statement criticizing the study, and calling it "unfocused, unrealistic, and rather unsafe." According to Steve Pretanik, the Council's director of science and technology, only two strains of the Enterococcus bacterium detected by the researchers are potentially harmful to humans.

Even Bill Satterfield, executive director of nonprofit Delmarva Poultry Industry Inc., based in Georgetown, Del., raised questions with the "unrealistic" conditions used in the study. He called it the latest attempt to "discredit and embarrass the industry."