EVALUATION OF A NEW TIME-TEMPERATURE INTEGRATOR IN PILOT-PLANT CONDITIONS

Pilot plant studies were carried out to evaluate the accuracy and gene ral performance of a new Time Temperature Integrator based on a gelled mixture of alginate-starch and mushroom puree over a temperature rang e of 115 to 125 degrees C. New thermal resistance data were also obtai ned for Bacillus stearothermophilus spores heated to high temperatures (121-135 degrees C), which are necessary for calculating the theoreti cal and experimental sterilization levels reached in the Integrator du ring pilot plant experiments. The results indicate that the decimal re duction coefficient (D) value of the gelled samples was higher than th at of double-distilled water and ungelled samples under the same condi tions. A mathematical model, improved by the use of recently measured D values, was able to predict the ability of the new Integrator to kil l microorganisms extremely well, such that then were no significant di fferences between predicted and measured values. The number of microor ganisms surviving in the Time Temperature Integrator when heated in an acidified brine was less than that surviving when heated in unacidifi ed brine, for all the conditions studied. This result indicates that t here is a good exchange capacity between the integrator and the surrou nding medium, with the spores immobilized in the integrator being subj ected to stress conditions similar to those found in real food.