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Micro-Exam2
Micro 7
Question | Answer |
---|---|
What is TDP? | Thermal Death Point (TDP) is the lowest temperature at which all cells in a culture are killed in 10 minutes by heat. |
What is TDT? | Thermal Death Time (TDT) is the time during which all cells in a culture are killed by heat. |
What is DRT? | Death Reduction Time is the minutes it takes to kill 90% of a population at a given temperature. |
List the 2 methods to evaluate the effectiveness of a disinfectant? | 1. Use-dilution tests 2. the disk-diffusion method |
What happens during the use-dilution test? | 1. Metal rings dipped in test bacteria are dried 2. Dried cultures are placed in disinfectant for 10 min at 20 degrees Celsius 3. Rings are transferred to culture media to determine whether bacteria survived treatment |
What happens during the disk-diffusion method? The one we used in class with the dots of paper. | 1. filter paper is soaked with chemical and placed on agar plate that's been inoculated and incubated with test organism 2. after incubation, if chemical is effective, a clear zone representing inhibition of growth can be seen around the disk. |
What bacteria are used to determine the effectiveness of disinfectants? | Clostridium sporogenes, Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus pneumoniae, Streptococcus algalacitiae, Escherichia coli, Pseudomonas aeruginosa, |