Peanut butter is a food product usually consisting of roasted and ground peanuts, usually salted and sometimes sweetened. It is commonly sold in grocery stores, but can be made at home. It is sometimes referred to by its abbreviation, "P.B." Many styles are available; the most popular are creamy (smooth) and crunchy, but honey-roasted, wholenut varieties and those mixed with chocolate can also be found. Creamy peanut butter is made by grinding all of the mixture very finely. The crunchier styles add larger pieces of peanut back into the creamy mixture after grinding. Used in sandwiches (particularly the classic peanut butter and jelly sandwich), candy (Reese's Pieces, for example), cookies and pastry, it is a good source of protein, and is popular with children. Elvis Presley made famous a version of the peanut butter sandwich with banana (either mashed or whole) that was grilled or fried, and may have contained bacon. Peanut butter is popular mainly in the United States and Canada, and little known in Europe. It is often mentioned as one of the foods you must grow up with to appreciate. Most people not used to it find the taste very odd. In this regard, an analogy can be drawn with marmite, popular in Britain, and Vegemite, popular in Australia. For people with peanut allergy, the concentration of nuts in peanut butter can cause fatal anaphylactic shock. The peanut plant is susceptible to the ground mold which produces aflatoxin, and contamination in peanut butter is possible .