Methods for wavelength calibration of spectrometers are provided which achieve better calibration accuracies than conventional peak search methods. The fiber optic interface assemblies include a receptacle configured to matingly engage with a plug of a fiber optic cable assembly. The scarf plate is placed into a rotating drum having snack food product. Lastly, a shoelace storage compartment formed within the member and receives the free ends of the shoe lace after one of each of the free ends has passed through at least one of the pair of openings.