Developing suitable smart TTI labels to match specific monitoring requirements: The case of Vibrio spp. growth during transportation of oysters

• Mathematical models were developed for Vibrio parahaemolyticus and Vibrio vulnificus growth based on literature data.
• Appropriate TTI were designed that predict one and three doublings of V. parahaemolyticus and V. vulnificus.
• The results indicate that the response of the Vibrio-TTI follow adequatelythe growth models of the two Vibrio species.
• Mathematical models can be useful tools for predicting Vibrio spp. growthin oysters for known time temperature conditions.

Time-temperature control is a critical issue in food logistics and the effective tracking of cold chain conditions is one of the main points to be addressed. There is a need for development and standardization of labels with a flexible range of temperature sensitivity, expressed by activation energy and of response time. Time Temperature Integrators (TTI) are inexpensive, active smart labels that show the time-temperature history of the food product to which they are attached. Enzymatic TTIs are based on a pH decrease resulting from the temperature-dependent enzymatic hydrolysis of a lipid substrate. The colour change of a pH indicator in the solution can be visually assessed or measured instrumentally. The considerations that allow for targeted design of the response characteristics of this type of TTI are the concentration of the enzyme and choice of substrate. This study applied predictive models for growth of Vibrio parahaemolyticus (VP) and Vibrio vulnificus (VV) growth in oysters and used the information from that work to design enzymatic TTI smart labels with response kinetics suitable for indicating the growth potential of Vibrio spp. during the transportation of oysters from harvest to storage for further distribution and sale. The results of the study indicated that the VV- and VP-TTIs developed in this study may be an effective and cost-effective tool for validating improved handling and cooling procedures and for monitoring the transport of oysters.