Interesting
"Beef tripe is usually made from only the first three chambers of a cow's stomach: the rumen (blanket/flat/smooth tripe), the reticulum (honeycomb and pocket tripe), and the omasum (book/bible/leaf tripe). Abomasum (reed) tripe is seen much less frequently, owing to its glandular tissue content. Tripe is also produced from sheep, goats, pigs, and deer. Unwashed (or "green") tripe includes some of the stomach's last content, giving it an unpleasant odor and causing it to be considered unfit for human consumption. However, this content is desirable to dogs and many other carnivores and is often used in pet food. Though it is called "green," because it has a high chlorophyll content a green substrate, in reality it is often grayish brown as a result of other undigested compounds."
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The tripe found in most markets today is the lining of beef stomach, though that from pork and sheep also fall under the definition. There are two beef stomach chambers and three kinds of tripe, all of which are tough and require long cooking. The best tripe, from the second stomach chamber, is called honeycomb tripe because the inner side has a pattern similiar to a honeycomb. It's the most tender and subtly flavored. Pocket tripe is cut from the end of the second stomach chamber. It's shaped like a pocket with the inside also being honeycombed. The least desirable plain or smooth tripe (with a smooth texture on both sides) comes from the first stomach. Tripe is available fresh (which is actually partially cooked by the packer) in most supermarkets. Choose tripe with a pale off-white color and store for up to a day in the refrigerator. Tripe is also available pickled and canned. The most famous French dish using this variety meat is the Norman dish called tripes à la mode de Caen-tripe braised with carrots, onions and cider. In Spanish-speaking countries, menudo (tripe soup) is a well-known favorite
