Recent results on the hurdle technology: measuring of combined hurdles.

摘要

The fluctuation in 3 treatments/hurdles, i.e., temperature (gradient 17-27 degrees C, step 1 degrees C), water activity (a< sub>w of 0.990, 0.985 and 0.980), and sodium nitrite as a preservative, was examined with regard to the activity of Escherichia coli. The bacterial counts of the inoculum were 1x103 and 1x106 colony forming units (cfu)/ml. In no case that the hypothesis of simple additive effect between different hurdles was sufficient and correct. The bacterium showed an extremely variable behaviour pattern. The investigations presented here document the necessity to consider the "hurdle-model" from a quantitative point of view. Environmental conditions such as temperature can influence microbial activity, as well as the efficiency of preservatives, such as sodium nitrite.