Researchers in the US have said they may have found a method of beating the potentially lethal food poisoning bacteria listeria. Professor Jimmy Keeton and colleagues at Texas A&M University say a simple organic acid can stop the harmful bug. Studying the effects of a number of different substances on frankfurters infected with a high level of listeria, the researchers found that acidified calcium sulphate was the only substance of those tested that could kill the bacteria and prevent it from returning.