The Slop Pass
Slop is a food eaten by Have Nots. Not much is known about it, other than that it tastes horrible, there was a another way to avoid Slop then being Head of Household or a Have. Being on slop may also be avoided if you have a slop pass.
Slop replaced Peanut Butter and Jelly Sandwiches, which were formerly eaten by House Guests that lost the food challenge. The first appearance of Slop was in Big Brother All Stars, and has appeared in every season since.
It has been speculated that Slop is really Bill Pearl's High Protein Oatmeal - Unsweetened, which has many of the essential nutrients, vitamins, etc. to maintain a healthy diet for the HouseGuests.