<p>A colorimetric indicator, which is used to verify the freshness of ready-to-eat foods (REF), such as mushroom kebab, was created using the anthocyanins from sweet potatoes (<i>Ipomoea batatas L.</i>); the mushroom was a white oyster mushroom (Pleurotus ostreatus). The indicator was created by combining PVA (polyvinyl alcohol) with PSPA (purple sweet potato anthocyanins) impregnated with bacterial cellulose (nata de coco) as an indicator film. The kebab’s freshness was assessed using TPC (total plate count), pH, and sensory evaluation (color and odor). The results showed that the indicator was purple when the kebab was fresh, moderate when its light purple, and green when it began to deteriorate. According to the ImageJ application, the mean Red of the indicator color value rose as the kebab’s freshness level dropped. Since it can distinguish between spoilage and fresh kebabs, the anthocyanin-based indicator film is suitable as a freshness indicator for kebabs.</p>