Swan Brothers Dairy Inc, a ready-to-eat cheese and milk producer in Oklahoma, violated Current Good Manufacturing Practice (CGMP) and Hazard Analysis and Risk-Based Preventive Controls regulations when FDA inspectors found Listeria monocytogenes contamination in environmental swabs collected throughout the facility. The inspection was triggered after a hospitalized listeriosis case was linked to the company's unpasteurized milk, leading to a voluntary recall of their unpasteurized milk and cheese products. FDA determined the facility's ready-to-eat cheese products were adulterated because they were prepared, packed, and held under insanitary conditions that may have contaminated them with a human pathogen capable of causing serious illness.