Development of the indicator to warn deviant temperature raise in cold chain

Abstract

The purpose of this study was to develop low cost color indicators of temperature abuse in the cold chain. To develop the indicators, bacterial strain sk22 isolated from commercial cod was used. Strain sk22 can grow and produce acid from carbohydrate at 4℃. Incubating sk22 in modified Oxidation- Fermentation broth at 12℃ (with initial inoculums levels of 10⁶ and 10³ CFU/ml) resulted in color changes of 35 and 72 hours respectively. Further, addition of buffer delayed color changes. Therefore by adjusting inoculum levels and/or buffer concentration, timing of color change could be controlled. To make the indicator safe for food use, the suitability of nine pigments and food grade buffers was tested to judge their effects on the color change. Red cabbage pigment was the most suitable one of the tested pigments because color change was clear. Furthermore, addition of food grade ammonium sulfate as a buffer enhanced clarity of color change.