Food spoilage causes chemical changes that are not always easy to detect by appearance alone. To provide a clearer indication of freshness and quality, researchers at Kyushu University have developed a smart packaging film that changes color and glows under ultraviolet (UV) light as meat loses freshness. Tested with refrigerated mutton, the film responds to compounds released during spoilage, offering two ways to track changes in food quality. The findings are published in the Chemical Engineering Journal.