Sorry for the length:
About topical sterilization (to get rid of spores) not just disinfection . . . . .
From:
https://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_Nov_2008.pdf
“Sterilization describes a process that destroys or eliminates all forms of microbial life and is carried out in health-care facilities by physical or chemical methods. Steam under pressure, dry heat, EtO (ethylene oxide) gas, hydrogen peroxide gas, and liquid chemicals are the principal sterilizing agents used in health-care facilities. Sterilization is intended to convey an absolute meaning; unfortunately, however, some health professionals and the technical and commercial literature refer to “disinfection” as “sterilization” and items as “partially sterile.” (
comment - this is like a little bit pregnant). When chemicals are used to destroy all forms of microbiologic life, they can be called chemical sterilants. These same germicides used for shorter exposure periods also can be part of the disinfection process (i.e., high-level disinfection).
Disinfection describes a process that eliminates many or all pathogenic microorganisms, except bacterial spores, on inanimate objects (Tables 1 and 2). In health-care settings, objects usually are disinfected by liquid chemicals . . . . Each of the various factors that affect the efficacy of disinfection can nullify or limit the efficacy of the process.
Factors that affect the efficacy of both disinfection and sterilization include prior cleaning of the
object; organic and inorganic load present; type and level of microbial contamination; concentration of and exposure time to the germicide; physical nature of the object (e.g., crevices, hinges, and lumens); presence of biofilms; temperature and pH of the disinfection process; and in some cases, relative humidity of the sterilization process (e.g., ethylene oxide).
Unlike sterilization, disinfection is not sporicidal (
think of black knot fungus here). A few disinfectants will kill spores with prolonged exposure times (3–12 hours); these are called chemical sterilants. At similar concentrations but with shorter exposure periods (e.g., 20 minutes for 2% glutaraldehyde), these same disinfectants will kill all microorganisms except large numbers of bacterial spores; they are called high-level disinfectants. Low- level disinfectants can kill most vegetative bacteria, some fungi, and some viruses in a practical period of time (<10 minutes). Intermediate-level disinfectants might be cidal for mycobacteria, vegetative bacteria, most viruses, and most fungi but do not necessarily kill bacterial spores. Germicides differ markedly, primarily in their antimicrobial spectrum and rapidity of action.”
Wow - Short story - see pp 104-105, they recommend
K, Ethyl or isopropyl alcohol (70-90%)
L, Sodium hypochlorite (5.25-6.15% household bleach diluted 1:500 provides >100 ppm available chlorine)
M, Phenolic germicidal detergent solution (follow product label for use-dilution)
N, Iodophor germicidal detergent solution (follow product label for use-dilution)
O, Quaternary ammonium germicidal detergent solution (follow product label for use-dilution)
(But some alcohols (
like methanol, for example) are not recommended for sterilizing . . . materials principally because they lack sporicidal action . . . .)
Some more pertinent blah from this document:
"The Table in the CDC Guideline for Environmental Control prepared in 1981 as a guide to the appropriate selection and use of disinfectants has undergone several important changes (Table 1). 15 First, formaldehyde-alcohol has been deleted as a recommended chemical sterilant or high-level disinfectant because it is irritating and toxic and not commonly used. Second, several new chemical sterilants have been added, including hydrogen peroxide, peracetic acid 58, 69, 70, and peracetic acid and hydrogen peroxide in combination. Third, 3% phenolics and iodophors have been deleted as high-level disinfectants because of their unproven efficacy against bacterial spores, M. tuberculosis, and/or some fungi. 55, 71 Fourth, isopropyl alcohol and ethyl alcohol have been excluded as high-level disinfectants 15 because of their inability to inactivate bacterial spores and because of the inability of isopropyl alcohol to inactivate hydrophilic viruses (i.e., poliovirus, coxsackie virus). 72 Fifth, a 1:16 dilution of 2.0% glutaraldehyde-7.05% phenol-1.20% sodium phenate (which contained 0.125% glutaraldehyde, 0.440% phenol, and 0.075% sodium phenate when diluted) has been deleted as a high-level disinfectant because this product was removed from the marketplace in December 1991 because of a lack of bactericidal activity in the presence of organic matter; a lack of fungicidal, tuberculocidal and sporicidal activity; and reduced virucidal activity. 49, 55, 56, 71, 73-79 Sixth, the exposure time required to achieve high-level disinfection has been changed from 10-30 minutes to 12 minutes or more depending on the FDA-cleared label claim and the scientific literature. 27, 55, 69, 76, 80-84 A glutaraldehyde and an ortho-phthalaldehyde have an FDA-cleared label claim of 5 minutes when used at 35oC and 25oC, respectively, in an automated endoscope reprocessor with FDA-cleared capability to maintain the solution at the appropriate temperature."
Lots more med info available regarding sterilization/ infection control
I use 99% isopropyl alcohol on our tools and sometimes bleach solution (but it can be really hard on metal tools) between cuts. It does slow work down but we really try our best to not spread badness around. Cleaning chainsaws - best of luck! Some of the other stuff (including commercial products) can be toxic (formaldehyde, gluteraldehye, etc) to people, as well as even causing skin rashes so watch the need for PPE (see the manufacturers MSDS).
Hope that helps.
