"Some brands of peanut butter may contain a small amount of added partially hydrogenated vegetable oils, which are high in trans fatty acids, thought to be a cause of atherosclerosis, coronary heart disease, and stroke; these oils are added to prevent the peanut oil from separating. Natural peanut butter and peanuts do not contain partially hydrogenated oils. A U.S. Agricultural Research Service (ARS) survey of commercial peanut butters in the U.S. showed the presence of trans fat, but at very low levels.[12]
At least one study has found that peanut oil caused relatively heavy clogging of arteries. Robert Wissler of the University of Chicago reported that diets high in peanut oil, when combined with cholesterol intake, clogged the arteries of Rhesus monkeys more than butterfat.[13]
Peanut butter can harbor Salmonella and cause salmonellosis, as in the Salmonella outbreak in the United States in 2007.[14] In 2009, due to mishandling and apparent criminal negligence at a single Peanut Corporation of America factory in Blakely, Georgia, Salmonella was found in 46 states[15] in peanut-butter-based products such as crackers, peanut-butter cookies, and dog treats. It has claimed at least nine human lives as of 17 March 2009 and made at least 691 people sick in the United States.[16][17]"
