Field verification of food quality monitoring in the cold chain by using a laccase time–temperature Indicator label

Abstract This study developed a laccase time–temperature indicator label (LTTIL) by immobilizing laccase on an electrospun fibers to form the LTTI film and reacted with guaiacol solution for coloration. Field verification was performed to validate the function of the LTTIL in monitoring food quality changes in cold chain under temperature fluctuations. The time required to reach a total plate count of 6 log CFU/g was regarded as the critical point of fresh-cut cucumber (FCC) deterioration (CPTPC). A critical point of LTTIL coloration (CPLTTIL), was also set to indicate the significantly darker of LTTIL. The field verification experiment revealed that when the LTTIL with 0.10 mM NaN3 was applied, the CPLTTIL was attained at 132.8 h after the experiment start, whereas the CPTPC was attained at 139.2 h, resulting in a low prediction error of approximately 4.6%. Therefore, the LTTIL is considered to be effectively used to monitor FCC quality changes in the cold chain and accurately evaluate their freshness.