Howdy,

I make cold press soap and to better preserve my soaps, I add grapefruit seed extract. I know it to be a very powerful antioxidant and antimicrobial as well, and Lowe and behold, I find this while shopping around for my soap ingredients:

GRAPEFRUIT SEED EXTRACT (GSE)

While not yet recognized by the Wilderness Medical Society, the use of Grapefruit Seed Extract (GSE) is gaining popularity as a water purification treatment. Lab tests indicate that GSE is effective against a wide range of pathogens, including viruses. Many medical practitioners have successfully used GSE to treat bacterial, protozoan, fungal, and viral infections. While the Federal Drug Administration (FDA) researchers and the World Health Organization (WHO) do not yet recommend GSE as a water purification method, they do endorse as a safe and effective treatment for numerous conditions (equal or superior to conventional anti-microbials). Manufacturers of GSE recommend it for treating water and back up their statements with in vitro (lab) tests and testimonials. As a water treatment GSE is very attractive because it is fast, easy to carry and use, may be used as a treatment for a variety of infections and conditions (eg: prevents Traveler's Diarrhea), has no side effects, is safe for long term use, and is inexpensive. Its only apparent disadvantage is its bitter taste and acidity (a possible problem for those with pre-existing acidic problems).

GSE is made from organic grapefruit seeds, pulp, and white membranes (details about the process and the type of active compounds are readily available in the literature). In concentrated form it is highly acidic and unsuitable for human consumption; however, when diluted with vegetable glycerine or water it is a highly effective antimicrobial. Research indicates that GSE appears to disrupt the cytoplasmic membrane in such a way that the organism is unable to uptake necessary amino acids. GSE also causes minor leakage of cellular contents and inhibits cellular respiration -all not good for the invading organism. can affect a wide variety of pathogens without adverse affect on animal life. Nor do they know how GSE affects viruses since viruses do not have a cell membrane of their own. But they do know that it is effective against an overwhelming number of pathogens.

GSE is available as a liquid or powder from numerous manufacturers. Although the powder is tasteless (liquid GSE is bitter), liquid GSE is more suitable for water purification since it is easier to vary the dose according to need and dissolves more quickly in water. Because the concentration of GSE products vary according to the manufacturer, you should follow the directions included with the product you buy. Note that water-based (versus glycerine based) GSE dissolves faster, thus decreasing the contact time. The recommended dosage for Traveler's Friend (a water based GSE product made and distributed by NutriBiotic) is 3-5 gtts (drops) per glass or 20-30 gtts per gallon; contact time is ten minutes. Consider extending the contact time to 20 or 30 minutes if the water is cold. Liquid GSE is available at most health food stores and from our website (www.Wild MedCenter.com).
http://www.globalhealingcenter.com/benefits-of/grapefruit-seed-extract

Could be another alternative for water purification. Just thought I'd share.