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Temperature monitoring and remaining shelf lifes calculations by using TTIs

This software tool demonstrates how TTIs somethink about TTIs...       can be used to control the cold chain and to predict the remaining shelf life of fresh poultry in diffferent steps of the chain. The prediction is based on the colour value of the TTI. The colour value is measured by a spectrophotometerThe discoloration process of TTIs is described by the square value SV of the CIE Lab colour system (L: lightness; a: red and green; b: yellow and blue). A high SV value corresponds to a high discoloration of the TTIs.      .
Instruction: You enter a TTI-value measured by the spectrophotometer and a certain constant storage temperature. The program will calculate the remaining shelf life and determines whether the cold chain was satisfied or not. Extendet Modus: Further, on you can enter a dynamic temperature profile for the future to calculate the residual shelf life

Enter the shelf life of the TTI:


temperature to assure the shelf life:


choose a TTI:

Something about the product
measured TTI-value (manual)description       :
30 SV Value 80

read automatic TTI-value (hardware required)description       :
expected storage temperature:
0 C 20

date of packaging (YY MM DD -- h m): --
alternative: Time span in hours after packaging
(this overwrites the date of packaging):

Background information

The algorithm bases on many experiments, that mostly have been conducted by the ccm-group of the University of Bonn during the last ten years and that are still ongoing. The experiments focus on different topics, that can be classified as follows:

  • Experiments to investigate the microbiological growth of bacteria under different environmental conditions.
  • experiments to investigate the change of sensory parameters in dependency of time and temperature,
  • experiments to determine correlations between the microbiological and sensory parameters,
  • experiments to investigate, whether specific TTIs (Time Temperature Indicators) show a similar behaviour in its kinematics like specific food and whether specific TTIs can initialized for specific food products,
  • experiments to determine product specific thresholds that indicate the end of the shelf life in form of sensory and microbiological parameters as well as color-values of the investigated TTIs.
Based on those experiments many different mathematical models (Gomperts, Logistic Functions, Linear Functions, Polynomial Functions, Square-Root-Models or Arrhenius) have been checked on their ability to describe the measured values in dependency of time and temperature.

The simulation of shelf lives resp. the "Freshness Index" FI on this webpage bases currently on a multi-stage-model, where the functionality of FI in dependency of the time, as a last stage, follows a logistical function within a time-interval with constant temperatures. The initial parameters of the function are estimations out of the results of different experiments. The parameters dependency of temperature were estimated with the help of the Arrhenius-Model and with linear regressions. To ensure, that the FI-values at the end of one time-interval with a constant temperature match to the following time-interval, one of the growth parameters gets adjusted.

Finally, the results got evaluated by comparisons of simulated values and measured values. The presented software is only a short demonstration. Please contact us for more details.

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