EFFECT OF LYOPHILIZATION ON THE MECHANICAL CHARACTERISTICS OF A LARGEPARTICLE AND ON THE BEHAVIOR OF IMMOBILIZED BACTERIAL SPARES

The mechanical stability of the carrier and the behavior of the sensor element of a time-temperature integrator (TTI) after lyophilization a nd storage for 60 days at room temperature were studied. The results i ndicated that particles containing added starch at concentrations from 2 to 12% had good handling characteristics for use as TTI carriers, a lthough mechanical resistance was lower by comparison with freshly pre pared particles. Lyophilization reduced the number of viable microorga nisms by 17 to 25%, depending on the length of the storage period. Var iations were also observed in the count of surviving microorganisms af ter heating at 121 degrees C for 12 min. These variations, expressed a s decimal reductions in the number of microorganisms, might reflect an effect of lyophilization on the thermal resistance of the immobilized spores.