Staph Bacteria Taints About Half of US Meat It calls attention to use of antibiotics in livestock: Researchers By John Johnson, Newser Staff Posted Apr 15, 2011 2:16 PM CDT 14 comments Comments T-Bone porterhouse steaks. (AP Photo) (Newser) – Here's a happy thought with summer barbecue season just around the corner: A new study suggests that about half the meat sold in the US is contaminated with potentially harmful bacteria, the Los Angeles Times reports. Researchers tested beef, chicken, turkey, and pork from supermarkets around the country and found that 47% of the 136 samples had strains of Staphylococcus aureus, the bacteria that causes staph infections from the mild to the severe. Of those, 52% were resistant to at least three classes of antibiotics. Researchers think the source of the contamination is the animals, not improper handling, and they say it's likely the result of the widespread use of antibiotics in livestock. "We know that nearly half of our food supply's meat and poultry are contaminated with S. aureus, and more than half of those are multidrug resistant," says the lead author of the study in the journal Clinical Infectious Diseases. "What we don't know [is] how often these transfer to people. We need more studies to quantify the public health impact." In the meantime, the usual safety precautions apply, notes CNN: Cook meat thoroughly, keep raw meat from other other foods, and wash your hands after handling.