In most resorts they seem to gas all the wildlife every evening. Seriously, I'm not joking. They pump insecticide all over the place.
Be careful about anything that could have been washed in tap water, or made of tapwater - eg ice cubes - and any food that has been hand prepared but not cooked within an inch of burning to cinder.
What you need to know to protect yourself is that hand-washing practices are not always followed - many Egyptians' homes and flats have very rudimentary sanitation, and workers coming into tourist resorts from rural villages might be less aware of hygiene in food prep.
Currency can also be a source of stomach bugs, so using antibacterial wipes after handling it can be a good idea.