This can be completed in the first scene of the game and will no doubt happen often anyway. When you approach an item that can be scavenged you hold down Y to do so, but if you hold down LB at the same time, your character will search it faster. Sometimes this will result in you making more noise and attracting a few extra zombies. It happens by chance but if it doesn't happen on your first try it almost surely will within two or three tries.