MBIO 1010 Lecture Notes - Lecture 16: Ionizing Radiation, Membrane Technology, Electromagnetic Radiation
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General principles and growth control by heat (cid:894)continued (cid:895) The autoclave is a sealed device that uses steam under pressure (figure. 15psi = increases pressure which increases the pressure on the water molecules which keeps the hydrogen bonds attached on the oxygen so it stays in the liquid form. Microwaves, uv, x-rays, gamma rays, and electrons can reduce microbial growth . Uv has sufficient energy to cause modifications and breaks in dna : uv is useful for decontaminating surfaces. Electromagnetic radiation that produces ions and other reactive molecules generates electrons, hydroxyl radicals, and hydride radicals. Some microorganisms are more resistant to radiation than others. Amount of energy required to reduce viability tenfold is analogous to d value. Other physical control methods: radiation and filtration (cid:894)continued (cid:895) include cathode ray. Sources of radiation tubes, x-rays, and radioactive nuclides . Radiation is used for sterilization in the medical field and food industry .