With food production shifting away from traditional farm‐to‐table approaches to efficient multistep supply chains, the incidence of food contamination has increased. Consequently, pathogen testing via inefficient culture‐based methods has increased, despite its lack of real‐time capabilities and need for centralized facilities. While in situ pathogen detection would address these limitations and enable individual product monitoring, accurate detection within unprocessed, packaged food products without user manipulation has proven elusive. Herein, “Lab‐in‐a‐Package” is presented, a platform capable of sampling, concentrating, and detecting target pathogens within closed food packaging, without intervention. This system consists of a newly designed packaging tray and reagent‐infused membrane that can be paired universally with diverse pathogen sensors. The inclined food packaging tray maximizes fluid localization onto the sensing interface, while the membrane acts as a reagent‐immobilizing matrix and an antifouling barrier for the sensor. The platform is substantiated using a newly discovered
Salmonella‐responsive nucleic acid probe, which enables hands‐free detection of 103 colony forming units (CFU) g−1 target pathogen in a packaged whole chicken. The platform remains effective when contamination is introduced with toolsand surfaces, ensuring widespread efficacy. Its real‐world use for in situ detection is simulated using a handheld fluorescence scanner with smartphone connectivity.