Bung is a term used in the butchering industry for an animal's rectum. In order to prevent the spread of bacteria to saleable meat, before removal the bung is plugged at its open end and tied off on in the inside. Much research has been conducted on the clean removal of the bung.
In China, where the bung is a regular food item (known as zhi2-chang2 or "straight intestine"), the entire lower large intestine and bung of a slaughtered animal is usually cleaned by this process:
- squeezed until empty by running through the fingers
- the bottom is held shut and the tube is filled with water
- the water is sloshed around and then drained
- the tube is filled with water again and the upper mouth is made to fall into the tube, until it comes out the bottom and the whole tube is reversed
- scrubbed like mad
Butchers in China are quite adept at doing this quickly and sanitarily (the various steps are carried out as many times as necessary to ensure cleanness). The bung is eaten as a regular organ meat - stir-fried, for instance. The bung itself is thin. It is usually prepared cut into small pieces, not left in tubular form. The stir-fried bung has a distinctive texture - firm (al dente) on the outside and soft on the inside.
The end of the bung (familiarly known as the bunghole) is treated as a separate food item, known as da4-chang2-tou2 "the head of the large intestine". A sphincter muscle, it can be stir-fried so that it has the consistency of calamari rings.