House flies are flying vectors of disease. It has been shown that each
house fly can easily carry over one million bacteria on its body. Flies
breed in excrement and garbage. Once they land on your food, in order
to digest your food they; spit up on the food, stomp their little feet
in your food, suck up the slime they have created, then they defecate
and fly away.
Because of these habits, house flies can pose serious health threats by transmitting disease organisms. Some of the disease-causing agents shown to be transmitted by house flies to humans are: shigella spp. (dysentery and diarrhea = shigellosis), salmonella spp. (typhoid fever, Escherichia coli, (traveler's diarrhea), and Vibrio comma (cholera).
The Life Cycle of the Housefly: The housefly can go through complete metamorphosis, passing from egg to larva, pupa and adult, in as few as eight days. Other fly species have similar life cycles.
Prevent disease by Keeping a lid on it. Keep trash lids on and trash bags tide up. Don't let the flies in the house in the first place. Keep screen doors closed and in good working order. Think twice about eating something that a fly has landed on.