Florida's outbreak of listeria has so far led to at least one death, 22 hospitalizations and an ice cream recall since January. Humans get sick with listeria infections, or listeriosis, from eating soil-contaminated food, undercooked meat or dairy products that are raw, or unpasteurized. Listeria can cause convulsions, coma, miscarriage and birth defects. And it's the third leading cause of food poisoning deaths in the US. Avoiding unseen food hazards is the reason people often check the dates on food packaging. And printed with the month and year is often one of a dizzying array of phrases: "best by," "use...
