General view of an unidentified employee prepping a Perkin-Elmer Model 503 Atomic Absorption Spectrophotometer to analyze a food sample in the Kellogg Company Quality Assurance laboratory located in Battle Creek, Michigan. Per notations accompanying the photograph, the employee is seen inserting a hollow cathode lamp into the instrument. At the laboratory, atomic absorption spectroscopy was commonly used to analyze food samples for heavy metal content, part of Kellogg's efforts to maintain standards for purity and nutritive levels in its food products, as well as satisfy governmental nutritional labeling requirements.