Date: April 22, 2010 8:47:05
AM EDT
Subject: RE:
[DCHAS-L] Hand sanitizer
The
benefit of 70 % isopropyl alcohol over 99 % is that from a
microbiological viewpoint, 70 % IPA is more penetrating to
bacteria. Any surface
disinfectant should remain in contact with the surface for 30-60 seconds
before being wiped away (check the directions on a bottle of 409). A 70 % solution seems to
work better under this protocol.
The real
benefit of hand sanitizer is that because it is non-specific, bacteria,
fungi, and viruses are unlikely to become resistant to the effects
(compare this to the issues with antimicrobic hand soap or
antibiotics). The
thing to remember is that disinfection is not the same as cleaning. If your hands are grimy
(and many of our students in K-12 situations have dirty hands), the
alcohol gel will kill microbes where it contacts, but their hands will
stay dirty.
Furthermore, one of the primary reasons hand washing cuts down on
transmission of infection is the physical act of washing and using
soap. To that end,
plain old Ivory Soap will reduce infection transmission when used
properly.
The moral
of the story=97alcohol gel is helpful for disinfection but not for
cleaning. If I can, I
generally wash my hands after a lab experience. Fifteen seconds (the
=93happy birthday=94 rule) is enough. Just the same, I carry a
small bottle of alcohol gel for situations where hand washing is
inconvenient.
Edward J.
McGrath
Science
Supervisor
Red Clay Consolidated School
District
office:
(302) 552-3768
