Purpose: This study was aimed to kinetically evaluate the characteristics of the indicator at various patterns of temperature with a mathematical model. Microbial growth data previously published was also used for evaluation.
Methods: The indicator was stored at constant and dynamic temperatures in an incubator and the color of the indicator (delta E) was measured with a Tristimulus colorimeter (Konica-Minolta, Japan) with intervals during the storage. The color change was analyzed with a mathematical model. The growth of Pseudomonas fluorescens, a psychrophile in sterile chicken at various patterns of temperature was measured with a plating method. Microbial growth data at various patterns of temperature reported in published papers were also analyzed in terms of time and temperature.
Results: The color change of the indicator at a constant temperature ranging from 4°C to 32°C during the storage was successfully described with the model. With those data, the color change of the indicator at dynamic temperatures was precisely predicted. At the times at various patterns of temperature to reach a given color change of the indicator, the increase in microbial population in food was almost constant.
Significance: This study showed that the color change of the indicator successfully estimated microbial growth in food at various patterns of temperature, suggesting that it could be a useful TTI.