Which is not part of big mac?

The Big Mac is a popular sandwich offered by McDonald's, consisting of two beef patties, special sauce, lettuce, cheese, pickles, and onions, all sandwiched between a three-part sesame seed bun. If we are discussing the classic Big Mac, the item that is not typically included in the sandwich is bacon. While McDonald's offers variations of the Big Mac with bacon or other ingredients in some regions or limited-time promotions, bacon is not a standard component of the traditional Big Mac.