The Piophilidae are a family of "true flies", in the order Diptera. The so-called cheese flies are the best-known members, but most species of the Piophilidae are scavengers in animal products, carrion, and fungi. They may accordingly be important in forensic entomology and medical entomology. For a fly maggot, the larvae of many species have an unusually well-developed ability to leap when alarmed or when abandoning their larval food to pupate; they accordingly may be known as cheese skippers or other kinds of skippers according to their food source.

Casu martzu, sometimes spelled casu marzu, and also called casu modde, casu cundídu and casu fràzigu in Sardinian, is a traditional Sardinian sheep milk cheese that contains live insect larvae (maggots).