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FoodMicroLecture 22
Final Exam
Describe thermobacteriology. | Concerned with the relationship between bacteria and heat; studies efficacy of heat sterilization techniques; associated with low-acid canned foods/C. botulinum. |
Thermobacteriology processes must render the food ____ and ____. | safe, commercially stable |
Describe microbial death. | Failure of reproduction, absence of growth during opportunity. |
T or F: Viable but non culturable cells are considered dead. | True |
Name three physiological factors which affect microbial inactivation. | Growth medium, pH, temperature, competition, antimicrobials |
Define thermal death time. | Time necessary to inactivate a defined concentration of bacterial spores or vegetative cells at a specified temperature. |
T or F: Thermal death time depends on curve shape. | False |
For first order destruction, the level of microbial concentration depends on the _____ of product. | volume |
What are the three assumptions made to use the survival curve? | Even distribution of innoculum, linear response, isothermal temperature. |
Define transformation. | Used to get a linear response from a set of log values. |
T or F: The thermal death time curve is linear with temperature. | True |
Define lethal rate. | The equivalent time at a reference temperature needed to destroy the same number of microorganisms for the current product temperature. |
Define F-value. | The time in minutes needed to destroy a given number of organisms at a specific temperature. |
Minimum health sterilizing values are based on a 12 log reduction of _____. | C. botulinum |
Commercial sterility values are based on a 5 log reduction of _____. | C. sporogenes |