(CNN) New research finds banned antibiotics and even arsenic in poultry products.
Two recent studies raise questions about what may be in chicken.
The Johns Hopkins assistant professor who worked on both studies, said he was surprised at the findings.
The studies were brought to light by New York Times columnist Nicholas Kristof.
The goal was to look for antibiotics which are used for growth. But scientists tested for other chemicals too.
“It was a pure surprise. They were included as part of the chemical panel that we used to test for antibiotics which we did expect to find and it was quite shocking to us,” said Keeve Nachmanm, with
Johns Hopkins Center for Livable Future
Nachman said that in addition to finding four antibiotics banned more than five years ago, he also found the active ingredients of Tylenol and Benedryl, caffeine.
And even arsenic.
He said he's heard anecdotes from farmers that some over-the-counter medications are given to animals so they won't have tense muscles, which can lead to tougher meat.
But he says there is no evidence of an immediate danger to people eating chicken--because he didn't study chicken meat—he studied feather meal.
Feather meal is a byproduct used as a supplement to feed animals.
"We didn't look directly at chicken meat. So we can only make inferences as to what we think might be in the meat based on the feathers. And what it says to me is that we really need to do a more thorough investigation of what drug residues are left behind in chicken meat as a result of what we choose to feed animals."
The national chicken council is shooting down the studies.
They said, as the study's authors point out; this study looked only at feathers, not meat.
The group adds chickens in the United States produced for meat are not given arsenic as an additive in chicken feed, or any of the other compounds mentioned in this study.
A product that contained organic arsenic was removed from the market last year.
A veterinarian who works closely with the poultry industry also says inorganic arsenic is a common heavy metal found in soil and plants.
"Since most of the poultry's feed is either corn or 75% corn with 10 or 15 percent soy bean meal, there's a possibility there could be some low levels of inorganic arsenic in the corn and soy bean they eat, “ said Charles Hofacre with the Dept. of Avian Medicine, Univ. of Georgia
Nachman said while there may not be an immediate danger, more research is needed.
"It only tells us that it would be worth looking at meat because some of these residues may also be there. But we can't say with any certainty that they are."
A spokeswoman for the FDA said the agency hasn't had enough time to review the studies in depth.
And that the use of the antibiotics mentioned in the study have been prohibited in poultry since 2004.