Abstract: A storage structure is composed of a storage rack having a plurality of storage bays, each of which is adapted to store a bundle, such as a food-related bundle having a pallet and a number of boxes of food items positioned on the pallet. The storage bays are disposed in a plurality of rows between a first end of the storage rack and a second end of the storage rack, the rows including an upper row and a lower row. The storage structure has a transmitter for transmitting a beam of radiation and a receiver for receiving the beam of radiation. The transmitter is associated with the first end of the storage rack and is positioned to transmit the radiation beam in a direction substantially parallel to the side of the storage rack, and the receiver is associated with the second end of the storage rack. The storage structure has an alarm generator coupled to the receiver for generating an alarm when the radiation beam is interrupted by one of the bundles located on the storage rack.