Newsletter_07-2024_EN

natively a mop with a ready prepared disinfectant solution could
be used).
– Using overlapping mop strokes, wipe down half the floor area,
working methodically around the area starting at furthest reach
point and working towards yourself in a straight line. Replace the
mop wipe if the wipe becomes visibly contaminated or dry.
– NOTE: Particular attention should be paid to corners and edges.
– Leave the disinfectant solution on the surface for the manufacturer’s
recommended contact time to allow the disinfectant to be
effective.
– Remove the mop head and discard to waste.
– Fit a second mop head with ethanol impregnated mop wipe (alternatively
a mop with a ready prepared alcohol solution could be
used).
– After the allotted time, using the fresh mop head wipe down
using overlapping mop strokes to remove any residue, working
methodically around the area starting at furthest reach point and
working towards yourself in a straight line. Replace the mop wipe
if the wipe becomes visibly contaminated or dry.
Use of fumigation
Where disinfection is difficult, is it advisable to use fumigation?
Yes, and this is always advisable following events that can lead to
high rates of contamination, such as maintenance works or a facility
shutdown. Fumigation-based approaches are advantageous for
decontaminating the inside of buildings because they are easily dispersed,
penetrate into difficult to access areas, decontaminate the
interior volume of the space (not only surfaces) and are less labour
intensive than many spray based approaches. Optimal agents are hydrogen
peroxide and chlorine dioxide.
Attention needs to be paid to the concentration and dwell time,
and with controlling temperature and humidity, as well as the mechanism
of dispersing the fumigant. Each of these factors contributes
to the overall efficacy.
“The movement of material or equipment from lower grade or
unclassified area to higher-grade clean areas should be subject to
cleaning and disinfection commensurate with the risk and in line
with the CCS.”
The Contamination Control Strategy refers to risk-commensurate
cleaning and disinfection.
Validation
The validation of detergent and disinfectant products, as well as
the validation of cleaning is a very important step: what are the
mandatory activities?
Validation studies are broken down into three sections: suspension
tests (phase 1 and 2) to evaluate the reduction of a known organism
population inoculated directly into a sample of the liquid disinfectant,
surface tests (phase 2) that assess a disinfectant’s ability to reduce
the number of challenge organisms on an inoculated surface,
and field trials (phase 3) a final assessment of the environmental
monitoring data to validate the approach.
Suspension methods evaluate the reduction= of a known organism
population inoculated directly into a sample of the liquid disinfectant.
Following inoculation and the observation of a predetermined
contact time, samples of the inoculated substance are removed,
neutralized and evaluated for survivors as compared to an untreated
control suspension. Since the simulation of organism films on the
specific environmental surface types are not accounted for in this
method, it is recommended that suspension-based tests be used
only for initial disinfectant screening purposes.
Surface testing involves aliquoting onto a surface coupon a mix
of the challenge organism and, where required, an interfering substance
(such a protein, to simulate dirty conditions). The surface
coupon will be fashioned from a representative surface in the cleanroom
(here several different materials will require testing in order to
show how the disinfectant performs). To this an amount of the test
disinfectant is added. The solutions are left for the required contact
time. Once the contact time has elapsed, the coupon is transferred
to a neutralizer solution. Then, as with the suspension test once sufficient
time has been given for neutralization, microbial survivors are
assessed by plating out or filtering the disinfectant neutralizer solution
using a microbial culture method.
A possible array of surfaces to consider (this will be
facility dependent) are:
– Stainless steel
– Glass
– Aluminum
– Epoxy
– Enamel
– Acrylic
– Mipolam
– Vinyl
– Hardwood
– Plastic
– Plexiglas
– Chromium
Once the testing has been performed, a report should be generated
that must conclude the disinfectant efficacy test outcome in relation
to the acceptance criteria. If a disinfectant passes the test, deeming
it suitable for use, cleanroom procedures must reflect the practices
adopted during the qualification, such as disinfectant concentration,
contact time and method of application to surfaces. The disinfectant’s
final adoption must then be based on a follow-up assessment
or field trial, which includes an evaluation of microbial counts and
species recovered.
Use of sterile concentrates
“Disinfectants and detergents used in grade A and grade B areas
should be sterile prior to use. Disinfectants used in grade C and D
may also be required to be sterile where determined in the CCS.
Where the disinfectants and detergents are diluted / prepared by
the sterile product manufacturer, this should be done in a manner to
prevent contamination and they should be monitored for microbial
contamination. Dilutions should be kept in previously cleaned containers
(and sterilized where applicable) and should only be stored
for the defined period. If the disinfectants and detergents are supplied
“ready-made” then results from certificates of analysis or conformance
can be accepted subject to successful completion of the
appropriate vendor qualification.”
In-house prep: in the latest Annex 1 version there is more focus
on both in-house preparation of detergents and disinfectants and on
the use of WFI water.
What do you think about the use of sterile concentrates
in cleaning and disinfection procedures?
The use of a concentrate that is made up or the use of ready-to-use
solutions, is a choice of each user. Both methods are effective.
www.reinraum.de | www.cleanroom-online.com NEWSLETTER | Edition EN 07-2024
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