About half of meat and poultry samples nationwide had evidence of S. aureus contamination, a study found. Fuse hide caption

itoggle caption Fuse

Workers move packages of meat at the South Gate Meat Company last June, when the Southern California meat distributor recalled 35,000 pounds of ground beef due to possible bacterial contamination. Adam Lau/AP hide caption

itoggle caption Adam Lau/AP

Cows that consume feed, grass or water contaminated with radioactive iodine-131 can concentrate the element in their milk. Peter Elvidge/iStockphoto.com hide caption

itoggle caption Peter Elvidge/iStockphoto.com