How can you tell when meat is spoiled? Turns out you can't always—the FDA doesn't even have an official definition for the term. Many microbiologists would say that meat has gone bad when 10 million microbes are present in a single gram—and get to work producing compounds with gag-inducing names like cadaverine and putrescine—but the human nose can't tell that anything's awry until there are somewhere between 100 million and 10 billion microbes per gram, by which point the meat is long past rotten. (Plus, meat tends to be packaged nowadays with carbon monoxide or other gases that keep it healthy-colored long after it's spoiled.)
Anyway, all that trivia and more comes from this quirky little Columbus Dispatch report about chemists who are trying to create an easy-to-read sensor that would alert people when the meat they're picking up in the grocery store is, in fact, unsafe. With upward of 110,000 cases of salmonellosis and E. coli infections in the United States alone each year, it's not a bad idea.