Unlike the other flies mentioned, flesh flies do not lay eggs, but small maggots. Flesh flies, like blow flies, will infest fresh meat, cooked or uncooked. Two other flies may be common pests in homes or businesses. Fruit flies are strongly attracted to the odor of rotting fruit and will sometimes be found around wine or vinegar. They may breed in overripe fruit or dirty trash containers.
Drain flies are small and dark grey.
They are very hairy-looking and may sometimes be called moth flies. These flies are most common in the bathroom. They breed in the slimy layer that forms inside the drain pipes of sinks or tubs. Removing that slime layer with a brush will end drain fly problems. Besides contaminating food with eggs and maggots, flies can carry bacteria that cause intestinal diseases.