STERILIZATION/DISINFECTION

Question 1

What chemical agents are used for gas sterilization?

Answer 1

Ethylene oxide, formaldehyde, beta-propiolacton (mutagenic, carcinogenic)

Question 2

Temperature and process of plasma sterilization?

Answer 2

Low temps (46 C +/- 4 C), dry air, H2O2 steam transformed to low temperature plasma by radiofrequency microwaves, transformed to O2 and water, used on metals, plastics and heat sensitive materials

Question 3

Methods of heat disinfection

Answer 3

Pasteurization, tyndallisation, boiling

Question 4

Tyndallisation procedure:

Answer 4

85 C for 30 min with incubation at 37 C – repeated several times

Question 5

Chemicals used for disinfection and their effects:

Answer 5

Cell membrane: detergents, alcohols (ethanol, propanol, isopropanol), isopropyl alcohol
Protein denaturation: organic acid (phenol, acetic acid, lactic acid), strong mineral (acid, alkaline)
Inhibit enzyme activity: heavy metal salts, alkylating agents
Oxidative agents: halogens (iodine, chlorine, chloramine), H2O2, KMnO4, dyes