Decontamination Steps

I. Heat 1- Moist heat or steam sterilization 2- Dry heat sterilization II. Low temperature (cold): 1. chemical a. ethylene oxide b. liquid sterilants: GLD, PAA, H2O2 2- plasma sterilizer III. Other sterilizers: 1- ionizing radiation 2- filtration 3- microwaves; in pharmaceutical industries

1- Chemical disinfection 1- Chemical disinfection 2- Boiling water 3- Pasteurization 4- Ultraviolet irradiation

1- Alcohol 70% (ethyl and isopropyl): Exposure time: 5 min at least Uses: 1- disinfection of a. external surfaces b. non invasive instruments 2- skin antiseptic, alone or added to iodine or chlorhexidine only works in presence of water and deactivated by organic soiling 2- Biguanides (chlorhexidine): 1- antiseptic for skin and mm, mouth wash (hexitol) 2- combined with. Alcohol as hand rub. Detergent as hand wash

3- Chlorine- active compounds (hypochlorite, house hold bleach): 1- decontamination of blood splashes and lab. Working surfaces ( ppm) 2- linen bleaching 2- linen bleaching 3- disinfection of water 4- Iodine based compounds (most effective antiseptics): include - tincture iodine (iodine in alcohol), staining and irritant - iodophores (iodine with neutral carrier), slow release of free iodine, more penetration, no staining and not irritant, betadine (30-50ppm) - iodophores (iodine with neutral carrier), slow release of free iodine, more penetration, no staining and not irritant, betadine (30-50ppm) used as skin antiseptic in surgical scrubbing and before surgery. Both halogens exert their bactericidal action by irreversible oxidation of the essential enzymes by the free radicals

5- Phenol containing preparations (phenol\lysol) ILD: Used for floors, walls and furniture Hexaphenol (detol) was used as antiseptic, was proven to cause neurological damage 6- Quternary ammonium compounds LLD: detergent either.anionic as soap or. Cationic as LLD.Used for routine cleaning of walls, floors or furniture. 7- Hydrogen peroxide: (oxidizing agent) HLD& sterilants 1- antiseptic for open wounds( kill anaerobes) 2-disinfection of soft contact lenses, some endoscopes 8- Peracetic acid: (oxidizing agent) HLD& sterilants HLD, strilizant of instruments as endoscopes 9- Glutaraldehyde(cidex) and Formaldehyde HLD& sterilants: GLD: HLD, sterilizant of instruments as endoscopes, respiratory and anaesthesia equipments FLD: gas not used now, found to be carcinogenic, only used in sterilization of HEPA filters.

Boiling at 100c for 20 min = HLD Only in emergencies It is heating at temperature less than 100c 1- Pasteurization of milk: heating at 63c for 30 min or at 72c for 20 sec, this is followed by rapid cooling. this destroys imp pathogenic bacteria as, MTB, salm, brucella, coxiella 2- Pasteurization of water: heating at 77c for 30 min. used for disinfection of items can ’ t withstand higher temp it may be coupled with chemical disinfection to achieve higher level of disinfection or even sterilization

UV is a low energy, non ionizing irradiation Its present in sun, artificially produced by mercury lamps Over exposure may cause eye damage and skin irritation Have extremely weak penetration power Used only for: Air and surface disinfection in Operating rooms Safety cabinet