Brains from cows over 30 months old at slaughter are no longer permitted to be sold for human consumption in the United States. Some restaurants have taken to serving pigs' brains instead of cows' brains due to concerns regarding
bovine spongiform encephalopathy, commonly known as "mad cow disease". Because pigs' brains are substantially smaller than cows' brains, the amount required for each sandwich increases. Each brain must be cleaned before being sliced and pigs' brains produce fewer slices. ==See also==