Kosher chicken contains more than twice as many antibiotic resistant E-coli strains than both conventional and organically raised chickens, according to a study released by the University of Arizona in early October. Between April and June of 2012, researchers bought 213 raw chicken samples from 15 retail locations across New York City. They purchased four types of chicken—conventional, organic, raised without antibiotics and kosher—and then screened each sample for E. coli and tested that E. coli’s resistance to 12 common antibiotics. Kosher chicken was resistant to more of the antibiotics than any of the other types. The study did not look into the cause, so it is not yet clear what it is in the kosher chicken production process that causes it to be less healthy, but the researchers from the four universities involved intend to look into it because the results, to them, were surprising as “kosher is perceived as clean and safe to consume.”

This result “belies the historical roots of kosher as a means to ensure food safety,” the study said.

The researchers posited that the higher resistance to antibiotics found in kosher chicken suggests that at some point in the kosher production of chicken, antibiotics are used more intensively than they are used in the production of any other sort.

E. coli causes 17.3 percent of clinical infections requiring hospitalization and 38.6 percent of all infections that do not require hospitalization. Not all strands of E. coli cause illness: some are harmless and some are even natural to the human body and vital to the production of Vitamin K. The harmful strands of the bacteria that can be found in chicken are killed when the poultry is cooked, but the real danger comes from cross contamination with the raw chicken, Moshe Morrison, a certified food safety manager in the National Registry of Food Safety, said.

“It’s very important that when you work with chicken that you have no cross contamination, meaning that it does not come in contact with any other food, especially cooked food. It would be wise to have a specific cutting board that you use only for raw chicken,” Morrison said.

To kill E. coli, a food product needs to be brought to 165 degrees. There is a serious risk of E. coli from knives, cutting boards and counters used for chicken and then for other food products. Morrison works at Smokey Joe’s where they have a specific area of the kitchen for raw chicken where no other products are allowed. “Maybe saying you have a separate cutting board is a little bit drastic, but the last thing you want to do is get your family sick,” Morrison said.