BIOL 211 Study Guide - Final Guide: Thermal Death Time, Opportunistic Infection, Ethylene Oxide
Document Summary
Aseptic surgery techniques prevent microbial contamination of wounds. Antisepsis: removal of pathogens from living tissue. Degerming: removal of microbes from a limited area. Sanitization: lower microbial counts on eating utensils. Bacterial populations die at a constant logarithmic rate. Thermal death point (tdp): lowest temperature at which all cells in a culture are killed in 10 minutes. Thermal death time (tdt): time to kill all cells in a culture. Minutes to kill 90% of a population at a given temperature. High temperature, short time: 72 c for 15 seconds. Ultra high temperature: 140 c for < 1 second. Ionizing radiation (x-rays, gamma rays, electrons beams) Microwaves kill by heat; not especially antimicrobial. Metal rings dipped in test bacteria are dried. Dried cultures are placed in disinfectant for 10 minutes at 20 c. Rings are transferred to culture media to determine whether bacteria survived treatment. Oligodynamic action - toxic effect of metal on cells. Sorbic acid, benzoic acid, and calcium propionate.
