ABSTRACT
Biological Time-Temperature Integrators (TTI) offer a novel approach for improving food safety and preventing spoilage. These smart tools relay, by an irreversible color shift, the cumulative effect of time and temperature on the microbial quality of food they are attached to. Among various types of TTI developed to date, biological TTI have the advantage of reproducing microbiological spoilage reactions that take place in food. They are based on the pH decline of a medium contained within the label, resulting from lactic acid bacteria (LAB) growth and acidification. When developing LAB-based TTI, careful LAB strain selection, research, and development efforts on TTI production are necessary to closely match the behavior of both spoilage and pathogenic microorganisms that grow during the storage of perishable foods. Covering a wide range of time-temperature profiles is a challenging goal involving research in different domains (microbiology, food science, modelling, etc.). This chapter describes the design and working principle of LAB-based TTI, how they are parametrized to be able to track a wide range shelf-lives and how their performance is evaluated. Current applications and future prospects of this innovative way of using lactic acid bacteria are also discussed.
