Granted...
"(Adapted from
www.cdc.gov 11,12)
Table 10. Prion Inactivation Methods for Reusable Instruments
and Surfaces
1. Immerse in 1 N NaOH, heat in a gravity displacement autoclave at 121ºC for 30 minutes. Clean
and sterilize by conventional means.
2. Immerse in 1 N NaOH or sodium hypochlorite (20,000 ppm) for 1 hours. Transfer into water and
autoclave (gravity displacement) at 121ºC for 1 hour. Clean and sterilize by conventional means.
3. Immerse in 1N NaOH or sodium hypochlorite (20,000) for 1 hour. Rinse instruments with water,
transfer to open pan and autoclave at 121ºC (gravity displacement) or 134ºC (porous load) for 1
hour. Clean and sterilize by conventional means.
4. Surfaces or heat-sensitive instruments can be treated with 2N NaOH or sodium hypochlorite
(20,000 ppm) for 1 hour. Ensure surfaces remain wet for entire period, then rinse well with water.
Before chemical treatment, it is strongly recommended that gross contamination of surfaces
be reduced because the presence of excess organic material will reduce the strength of either
NaOH or sodium hypochlorite solutions.
5. Environ LpH (EPA Reg. No. 1043-118) may be used on washable, hard, non-porous surfaces
(such as floors, tables, equipment, and counters), items (such as non-disposable instruments,
sharps, and sharp containers), and/or laboratory waste solutions (such as formalin or other
liquids). This product is currently being used under FIFRA Section 18 exemptions in a number of
states. Users should consult with the state environmental protection office prior to use.
Working Solutions 1 N NaOH equals 40 grams of NaOH per liter of water.
Solution should be prepared daily. A stock solution of 10 N NaOH can be prepared
and fresh 1:10 dilutions (1 part 10 N NaOH plus 9 parts water) used daily.
20,000 ppm sodium hypochlorite equals a 2% solution. Most commercial
household bleach contains 5.25% sodium hypochlorite, therefore, make a 1:2.5
dilution (1 part 5.25% bleach plus 1.5 parts water) to produce a 20,000 ppm
solution. This ratio can also be stated as two parts 5.25% bleach to three parts
water. Working solutions should be prepared daily.
CAUTION: Above solutions are corrosive and require suitable personal
protective equipment and proper secondary containment. These strong corrosive
solutions require careful disposal in accordance with local regulations.
Precautions in using NaOH or sodium hypochlorite solutions in autoclaves:
NaOH spills or gas may damage the autoclave if proper containers are not used.
The use of containers with a rim and lid designed for condensation to collect and
drip back into the pan is recommended. Persons who use this procedure should
be cautious in handling hot NaOH solution (post-autoclave) and in avoiding
potential exposure to gaseous NaOH; exercise caution during all sterilization
steps; and allow the autoclave, instruments, and solutions to cool down before
removal. Immersion in sodium hypochlorite bleach can cause severe damage to some instruments."
