金沙棋牌平台开户注册:Now gourmets may guzzle in safety

时间:2019-03-07 02:03:02166网络整理admin

By Nell Boyce in Washington DC A TEST for tainted oysters promises to make them less risky to eat. Oysters filter hundreds of litres of water every day. If the water contains traces of raw sewage they can pick up viruses that cause diseases in people. For example, oysters contaminated with enteric viruses were blamed for a serious outbreak in California last year. At present, public health officials rely on bacterial counts to screen oyster beds for possible sewage contamination. And when a cluster of people fall ill from eating oysters, epidemiologists can trace numbered lots of oysters back to where they grew and put a halt to harvesting in that area. However, health officials have no way of mesuring viral contamination directly. The low levels of virus that can cause disease make it hard to test for a virus by looking for its genetic material. Oysters also contain natural compounds that inhibit the polymerase chain reaction, which is used to amplify tiny quantities of DNA or RNA until there is enough to be detectable. Now these problems have been overcome by Ralph Baric of the University of North Carolina in Chapel Hill and Carol Shieh and Kevin Calci at the Food and Drug Administration’s Gulf Coast Seafood Laboratory on Dauphin Island, Alabama. The key to their new test is a way of washing the natural inhibitors out of the samples, which boosts the chances of recovering viral material. Using oysters deliberately contaminated with a safe strain of poliovirus,