Most picnickers would brush away flies from food, thinking nothing of bugs briefly landing on their sandwiches.  But a new study suggests the insects carry far more dangerous bacteria than previously thought, meaning sandwiches are best avoided if they have been contaminated by flies. Researchers at Penn State Eberly College of Science in the United States found that common houseflies carry

salmonella, e-coli and even bacteria which lead to stomach ulcers and deadly sepsis. The researchers say flies may have been overlooked by public health officials as a source of disease outbreaks.  Flies in urban areas were found to carry more bacteria than the countryside leading scientists to suggest avoiding city parks for a picnic, and eating food in more rural locations. READ MORE