Consumers Reports says that of 316 raw chicken breasts purchased at retail stores nationwide, 97 percent were contaminated with potentially harmful bacterial.

The most common bacteria detected on the meat was enterococcus, which was found on nearly 80 percent of chicken samples. Although enterococci are naturally found in the intestinal flora of both humans and animals, a handful of the genus's 17 species cause infections that are becoming increasingly difficult to treat due to increasing antibiotic resistance.

E. coli was second at just over 65 percent, and, like enteroccoci, while some strains of E. coli are harmless, others can result in diarrhea, urinary tract infections, respiratory illness and pneumonia. Campylobacte, known to cause diarrhea, cramping and fever, was the third most common at 43 percent.

Others included klebsiella pneumonia at just under 14 percent, salmonella at nearly 11 percent and staphylococcus aureus at just over 9 percent.

After evaluating every bacterium for antibiotic resistance, the testers found that nearly half of the chicken samples contained at least one multi-drug resistant bacteria.

"Our tests show consumers who buy chicken breast at their local grocery stores are very likely to get a sample that is contaminated and likely to get a bug that is multidrug resistant. When people get sick from resistant bacteria, treatment may be getting harder to find," said Dr. Urvashi Rangan, a toxicologist and Executive Director of the Consumer Reports Food Safety and Sustainability Center.

Meanwhile, a survey conducted by Consumers Reports' National Research Center found that, of a total of 1,005 participants, more than half thought chicken labeled as "natural" did not receive antibiotics or genetically modified feed, and more than one-third said they understood "natural" and "organic" to mean the same thing - none of which, the researchers said, is true.

What this shows, Rangan said, is that "consumers are making buying decisions based on label claims that they believe are offering them additional value when that is not in fact the case."

He then added: "The marketplace clearly needs to change to meet consumer expectations."