Metode fiziceMetode chimice

ETUVA

Sterilizarea ansei la bec Bunsen

Sterilizator pentru anse

STERILIZAREA PRIN FILTRARE

STERILIZAREA PRIN FILTRARE

1) să aibă o puternică acţiune antimicrobiană în concentraţii relativ reduse;

2) să prezinte un grad înalt de solubilitate în apă;

3) să aibă stabilitate în timp, sub formă activă (remanenţă);

4) să nu fie toxic pentru organismul uman, chiar în aplicaţii externe;

5) să nu se combine cu materii organice de pe tegumente care să-l inactiveze;

6) să-şi exercite efectele bactericide cu intensitate apropiată atât la temperatura camerei

cât şi la temperatura corpului uman;

7) să aibă capacitate mare de penetrare;

8) să nu degajeze un miros neplăcut, pe cât posibil;

9) să aibă un cost relativ scăzut.

CONDIŢIILE GENERALE PE CARE TREBUIE SĂ LE ÎNDEPLINEASCĂ UN AGENT CHIMIC DEZINFECTANT

Chemical Action Uses

Ethanol (50-70%) Denatures proteins and solubilizes lipids Antiseptic used on skin

Isopropanol (50-70%) Denatures proteins and solubilizes lipids Antiseptic used on skin

Phenolic compounds (e.g. carbolic acid, lysol, hexylresorcinol, hexachlorophene)

Denature proteins and disrupt cell membranes

Antiseptics at low concentrations; disinfectants at high concentrations

Silver nitrate (AgNO3)  Precipitates proteins General antiseptic and used in the eyes of newborns

Mercuric chloride Inactivates proteins by reacting with sulfide groups

Disinfectant, although occasionally used as an antiseptic on skin

Chlorine (Cl2) gas Forms hypochlorous acid (HClO), a strong oxidizing agent

Disinfect drinking water; general disinfectant

Tincture of Iodine (2% I in 70% alcohol) Inactivates proteins

Antiseptic used on skinDisinfection of drinking water

Colorants (crystal violet, metil-violet, briliant green, metilen blue) Bacteriostatic, weak bactericide Antiseptic used on skin

Ethylene oxide gas  Alkylating agentDisinfectant used to sterilize heat-sensitive objects such as rubber and plastics

Ozone Generates lethal oxygen radicals Purification of water, sewage

Detergents (e.g. quaternary ammonium compounds) Disrupts cell membranes Skin antiseptics and disinfectants

Metabolic antagonists (CO, cianures, para-fluorofenil-alanin) Interfere with normal metabolism

Bases and acids Precipitation of proteinsAldehides (formaldehide, glutaraldehide)

SUBSTANCE EFFECTIVE CONCENTRATION USES

Propionic acid and propionates 0.32% Antifungal agent in breads, cake, Swiss cheeses

Sorbic acid and sorbates 0.2% Antifungal agent in cheeses, jellies, syrups, cakes

Benzoic acid and benzoates 0.1% Antifungal agent in margarine, cider, relishes, soft drinks

Sodium diacetate 0.32% Antifungal agent in breads

Lactic acid unknown Antimicrobial agent in cheeses, buttermilk, yogurt and pickled foods

Sulfur dioxide, sulfites  200-300 ppm Antimicrobial agent in dried fruits, grapes, molasses

Sodium nitrite 200 ppm Antibacterial agent in cured meats, fishSodium chloride unknown Prevents microbial spoilage of meats, fish, etc.

Sugar unknown Prevents microbial spoilage of preserves, jams, syrups, jellies, etc.

Wood smoke unknown Prevents microbial spoilage of meats, fish, etc.

TYPE BRANDNAMES

ACTION SPECTRUM ADVANTAGES DISADVANTAGES

Chlorine Clorox. Purex(5.25'o sodiumhypochlorite)

Effective against bacteria and viruses.Generally used at a 1:30 dilution ofordinary household bleach (one ounceper quart of water). Needs 5 mincontact time. Rapidly inactivated byorganic materials.

Good disinfectant anddeodorizer. Inexpensive andavailable.

Caustic, rapidly inactivated by organicmaterial, loses effectiveness quickly,produces carcinogenic by-products, ruinsclothing.

Stabilizedchlorine dioxide

Oxy fresh Dent-

Effective against bacteria and viruses.Rapidly inactivated by organicmaterials.

Good disinfectant anddeodorizer. Diluted solutionis safe.

Not readily available. Expensive.Rapidly inactivated by organic material.Concentrated chlorine dioxide fumes may betoxic to lhins tissue-

Phenol. Lysol (phenol*,not benzylaininocium CI).Stericol. O-SylStaphene, 1-Stroke Environ.

Effective against many bacteria, fungiand some viruses. Requires 10 min.contact tune. May not work well x thepresence of organic material

Good bacterial and viraldisinfectant. Moderate cost.

High cone en nation, can irritate six eye. andlungs. Does not kill all bactena and viruses.May not work well in the presence of organicmaterial

Chlorhexidinegluconates

Nolvasac,Phisohex.Viiosan,Hititane.

Effective against most bacteria andsome yeast. Requires 10 mm. contacttune. Does not kill bacterial spores or\lntses.

Effective against bactena:non-toxic. Moderate-highcost.

Not effective against P;eudomonaz. Does notkill spores or viruses.

TYPE BRANDNAMES

ACTION SPECTRUM ADVANTAGES DISADVANTAGES

Quaternaryammoniumcompound.

Roccal-D.Quintacide.Paivoso!, Ki.or,Meiquat,Cervlcide

Cleaner and disinfectant.Effective against many types ofbacteria, some viruses, but not againstspores or fungi. Requites contact timeo: 10 min.

Effective against mostbacteria. Detergent helps toremove organic materialLow toxicity.

Expensive to purchase Initially, although it isused in dilute solution (0.1°* final}. Does notkill spores, fungi. Pzeudomona;, or someviruses.

Glutaraldehydes Wavecide,Cidex,Sporecide.Banacide.Sterol

Effective against bacteria, includingspores, and viruses. Wori. swell inpresence of organic material and is verystable compared to other disinfectants

Very stable and effective.

Expensive. Difficult to obtain.C an irritate skin, eyes and lungs.

Alcohols Ethanol is effective against a widevariety of pathogens if soaked forsufficient time (20-30 min).70% ethanol is considered mosteffective di-iniectant.

Bro3d range, low cost,readily available, non-toxic

Requires long contact time and evaporatesquickly so Items must be soaked in alcohol.Flammable.

Iodine. Vanodine,Betadyne.Povidone,Scrubodyne

EffecQve against most bacteria.Including spores, and some viruses.Requires 30 min. contact time. RapidlyInactivated by organic materials.

Good disinfectant. Readilyavailable. Long shelf life.Moderate cost.

Rapidly Inactivated by organic materials.Must be used in concentrated form, whichstains surfaces.

Pxe oil Pine-Sol Hexol

Pine oils have some disinfectantproperties, but they are not veryeffective.

Good for cleaning, low cost,non-toxic, readily available.

Not effective in killing pathogens.