Five people are making cream pies and sharing a kitchen. The kitchen has two refrigerators: Refrigerator A and Refrigerator B$.$ Juliet uses milk and butter from Refrigerator A and uses eggs from Refrigerator B$.$ Ryan uses butter from Refrigerator B and uses eggs and milk from Refrigerator A$.$ Zach uses milk from Refrigerator A and uses eggs and butter from Refrigerator B$.$ Dave uses milk and butter from Refrigerator B and uses eggs from Refrigerator A$.$ Tracy uses milk from Refrigerator B and uses eggs and butter from Refrigerator A$.$ The cream pies that are made by Ryan, Dave, and Tracy have a spoiled flavor to them. Which of the available ingredients most likely caused the pies to have this spoiled flavor?