BEE-L Archives

Informed Discussion of Beekeeping Issues and Bee Biology

BEE-L@COMMUNITY.LSOFT.COM

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Reply To:
Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
Date:
Mon, 27 Apr 2009 12:59:59 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (66 lines)
Some folks have mentioned using Chlorine Bleach as a sterilizer or sanitizer
for comb, etc. I can't comment on how effective that might be but I did want
to point out that standard bleach-water solutions aren't the most effective
sanitizer! With a little proper precaution, adding a weak acid to your bleach
solution can GREATLY increase the 'killing power' - it even kills anthrax
spores. 

Here's more info:

*Vinegar increases killing power of bleach*
Adding white vinegar to diluted household bleach greatly increases the
disinfecting power of the solution, making it strong enough to kill even
bacterial spores. Researchers from MicroChem Lab, Inc. in Euless, Texas,
report their findings today at the 2006 ASM Biodefense Research Meeting.

Sodium hypochlorite (NaOCl) in the form of laundry bleach is available in
most households. The concentrate is about 5.25 to 6 percent NaOCl, and the
pH value is about 12. Sodium hypochlorite is stable for many months at this
high alkaline pH value.

"Laundry bleach is commonly diluted about 10 to 25-fold with tap water to
about 2000 to 5000 parts per million of free available chlorine for use as
an environmental surface disinfectant, without regard to the pH value of the
diluted bleach. However, the pH value is very important for the
antimicrobial effectiveness of bleach," says Norman Miner, a researcher on
the study.

At alkaline pH values of about 8.5 or higher, more than 90 percent of the
bleach is in the form of the chlorite ion (OCl-), which is relatively
ineffective antimicrobially. At acidic pH values of about 6.8 or lower, more
than 80 percent of the bleach is in the form of hypochlorite (HOCl). HOCl is
about 80 to 200 times more antimicrobial than OCl-.

"Bleach is a much more effective antimicrobial chemical at an acidic pH
value than at the alkaline Ph value at which bleach is manufactured and
stored. A small amount of household vinegar is sufficient to lower the pH of
bleach to an acidic range," says Miner.

Miner and his colleagues compared the ability of alkaline (pH 11) and
acidified (pH 6) bleach dilutions to disinfect surfaces contaminated with
dried bacterial spores, considered the most resistant to disinfectants of
all microbes. The alkaline dilution was practically ineffective, killing all
of the spores on only 2.5 percent of the surfaces after 20 minutes. During
the same time period the acidified solution killed all of the spores on all
of the surfaces.

"Diluted bleach at an alkaline pH is a relatively poor disinfectant, but
acidified diluted bleach will virtually kill anything in 10 to 20 minutes,"
says Miner. "In the event of an emergency involving Bacillus anthracis
spores contaminating such environmental surfaces as counter tops, desk and
table tops, and floors, for example, virtually every household has a
sporicidal sterilant available in the form of diluted, acidified bleach."

Miner recommends first diluting one cup of household bleach in one gallon of
water and then adding one cup of white vinegar. 

http://www.eurekalert.org/pub_releases/2006-02/asfm-vik021306.php


- Mike

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned 
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html

ATOM RSS1 RSS2