So I've spent a couple hours researching this whole sterilization thing, concentrating on food-safe sterilization that can be done in a typical household (which rules out autoclaves). I concentrated on web sites from US Government agencies, colleges, and hospitals. Some other sites were perused hoping to find reference links to the above type of sites.
This is hardly complete, and may contain errors. I'm hoping that someone more knowledgable than me can shed some light on any particular point. Use at your own risk.
Also note that there are different strengths of cleaning:
Rinsing - with water
Cleaning - with soap and water
Sanitizing - killing bacteria and most other germs, but not necessarily fungi and spores
Sterilization - Killing most everything, but not porins
I'm trying to concentrate on Sterilization, but am finding that most of these solutions really do only sanitization for most of us with reasonable, feasible means. We probably don't need to use sterile items anyway - though it's always better to be safe.
Sterilization / Sanitization Methods
Irradiation: Beyond our means.
Dry heat (oven): 340F for 1 hour, 250F for 12 hours. Not good for many plastic items like bottles and disposable pipettes and eye-dropper caps and bulbs.
Boiling: Full boil for 20 minutes. Might be too hot for most plastic items we use, especially if they touch the hotter sides or bottom of the pot used. I may run a test if I get a chance. Even if HDPE and LDPE bottles can handle the high temps, the process will probably stress the seams and possibly deform the items. I doubt that this would work well on "rubber" eye-dropper bulbs.
Steam Heat (autoclave, pressure cooker): Autoclaves are not feasible for almost all of us. A pressure cooker could be used, but again it's not safe for most plastic items we use because of the heat required. Pressure Cookers reach a temperature of 250F or 121C at a pressure of 15 pounds and requires 30 minutes for the process to be effective.
Ultraviolet Light (See Nerf's post above): Great for clear items, like glass tubes. Hard to get into all areas inside bottles and opague items like eye-dropper bulbs. May not work through "clear" bottles or disposable pipettes which are really semi-transparent plastic. May work, but I can't find any information about how well ultraviolet light works through such semi-transparent plastics.
Microwaving: Microwaving for sterilization really works by heating, not irradiation. Microwave a damp sponge for 2 minutes and damn near everything will be dead except some porins and the toughest germs (like tuberculosis). Because of the heat required this is probably not good for most plastics we use.
Hydrogen peroxide: Typical 3% solution, the common stuff found in any store, works great. If the substance can handle the heavy oxidation, which I doubt is true considering that LDPE is permeable to oxygen. Hoever, hydrogen perozide comes in a plastic bottle - perhaps HDPE or PET? I don't know. Even if it is OK for the plastics we use, the fumes can be dangerous even in very low concentrations, so I have to consider hydrogen peroxide to be unsafe and not recommended.
Bleach solution: Bleach is a pretty thorough disinfectant. It is also a powerful oxidizing agent, so it might have similar tendencies to hydrogen peroxide above. However, household bleach is generally a 5% solution of sodium hypochlorite and we don't use that straight. Diluted even further to a 10% bleach solution, the sodium hypochlorite is reduced to a 0.5% solution, 1/6 of the common hydrogen peroxide solution. Even still, it's a powerful oxidizer and may cause issues with oxygen-permeable LDPE bottles and disposable pipettes. I guess this is out.
Alcohol (Isopropyl and rubbing alcohol) - For external use only, so they're out.
Alcohol (vodka or pure grain) - This stuff won't sterilize, but does a very good job of sanitizing if the alcholo is high proof and/or items are given a long soak. It can be ingested, and isn't considered harmful for inhalation as far as I know. This is probably the safest of the strong cleaning methods, even though it doesn't reach sterilization levels. Use the highest proof you can get and/or afford, and soak for a long time - at least overnight, but I've seen references that state 12 hours when using low-proof alcohol (which I assume means 80-proof). Even if we don't need the proof or time, it's better to be safe than sorry.
Summary
Boiling needs some investigation and testing.
If the boiling tests fail, alcohol - vodka or PGA - seems to be the strongest cleaning method which remains feasible to most of us.
Alcohol Cleaning Methodology
(Just my opinions)
1. Rinse with tap water
2. Fully submerge items in a soap & tap water solution. Agitate somehow to get coverage. Let soak for some time. (How long? 5 or 10 minutes?)
3. Rinse with tap water
4. Final rinse with distilled water
5. Fully submerge items in alcohol (vodka/PGA) in a covered container. Use the highest proof you can do, at least overnight but preferably 12 hours.
6. Rinse thoroughly with distilled water?
7. Air dry or very low-temp oven (150F)
Sound right? Am I missing anything? Any comments?
