ABCNews -- More than a billion oysters are harvested each year from the Gulf of Mexico. They're fried, broiled, barbecued, served Rockefeller and sucked down raw throughout the country. Nearly all the oysters consumed in the U.S. are farmed from cultures. And refrigeration makes them safe to eat year-round. But there is something to the old saying that oysters should only be consumed in months where the name includes an "R" (i.e. not in the summer): It is a bacteria called vibrio vulnificus. Of the very many people who eat those oysters, it is a pretty small subset -- 15 per year in the United States, on average -- who die from the bacteria vibrio vulnificus, which can become concentrated in oysters harvested in the summer and eaten raw. Another 15...