A farmer holds cucumbers in a field in Malaga, Spain. Cucumbers from Spain have been eyed as the source of a disease outbreak in Germany. Jorge Guerrero/AFP/Getty Images hide caption

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

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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

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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

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