YONKERS, NY – In an investigation of pork products, Consumer Reports claims to have discovered high rates of potentially harmful foodborne bacteria that are resistant to antibiotics.

Consumer Reports said its researchers tested and analyzed 148 samples of meat from pork chops and 50 ground pork samples from six US cities and found high rates of yersinia enterocolitica, a bacterium that can cause food poisoning. The organization also claimed that the majority of the yersinia and a "substantial portion" of several other bacteria found in the samples were resistant to antibiotics.

Additionally, a separate test for ractopamine found in very low levels in the analyzed samples. Consumer Reports tested 240 additional pork products. Ractopamine is approved for use in the United States, but the drug is banned in China, Taiwan and the European Union.

Other key findings include:

Yersinia enterocolitica was found in 69 percent of the tested pork samples. The bacterium is estimated to cause foodborne illness in about 100,000 Americans annually, especially children, and is associated with pork, according to Consumer Reports.

Salmonella, staphylococcus aureus, or listeria monocytogenes were found in 3 to 7 percent of samples. Consumer Reports found 11 percent harbored enterococcus, which can indicate fecal contamination and can cause non-foodborne related infections such as urinary-tract infections.

• Most of the bacteria found were resistant to at least one of the tested antibiotic drugs.

• Ground pork was more likely than pork chops to harbor pathogens.

• Very low, but detectible levels of ractopamine were found in about one-fifth of the samples tested for the drug. Beta-agonist drugs like ractopamine can cause restlessness, anxiety, fast heart rate and other effects. While levels found were below US and international limits, Consumers Union, the policy and action arm of Consumer Reports, calls for a ban on the drug, citing insufficient evidence that it is safe.

• Misleading and unapproved claims such as “no antibiotic growth promotants” and “no antibiotic residues” were found on some packages of pork and reported to the USDA for investigation.

• No labels disclose the use of ractopamine. Government standards for “no antibiotics used” and “no hormones added” claims do not prohibit the use of ractopamine.