gens will have the time, temperature,
nutrient and water required for their
growth and ability to form a biofilm.
Eventually, they will enter the product
stream. There are other benefits, such as
preventing pest issues, improving equipment reliability, improving people safety, etc., to consider when implementing
a robust PEC program at your facility.
The key point is to take a proactive
approach and clean
points before your
product is contaminated. Having the
PEC tasks included
in the master sanitation schedule will
also allow the team
to capture the knowledge and continue to
manage the tasks over
time. This will allow
the process to become
standardized and remain sustainable in
an ever-changing plant environment.
Where Do You Start?
For products susceptible to microbial
growth, assessing the postmicrobial reduction equipment would be the place
to start. If the hazard is a pest, then the
risk might be greater before the kill step.
For example, in bakeries, the microbiological hazards postbake are limited, but
the risk of pests in the flour receiving
and mixing areas is greater. Therefore,
in bakeries, focusing on the periodic
cleaning of equipment located upstream
of the oven might be a priority over
the equipment located downstream of
the oven. However, for ready-to-eat and
-drink products, equipment located after
the kill step will be the starting point.
The sanitary design principles from
the North American Meat Institute and
the Grocery Manufacturers Association
and their checklists are excellent tools to
assess your legacy equipment to deter-
mine where design gaps exist and where
PEC is required. It is often educational
to remove what appears to be a smooth
cover made of stainless steel to find a
part made of mild steel or a complex as-
sembly of parts under that cover. If your
commercialization process includes
equipment design review, it is likely that
you will uncover those niches during
the commercialization and be able to
implement a cleaning procedure before
there is an issue with the product.
A simple principle is to make sure
that all the parts can be cleaned and in-
spected routinely. If an assembly is too
complex to be disas-
sembled every time the
equipment is cleaned,
then it should have
its own periodic fre-
quency for disassem-
bly and deep cleaning.
Following a design
checklist as referenced
above, a multi-func-
tional team will look
for sandwiched parts,
liquid collection areas,
due to location and incompatible mate-
rials, just to name a few, and determine
a periodic cleaning frequency.
The equipment manufacturer should
also be contacted for their recommenda-
tion, although not all equipment manu-
facturers will be familiar with PEC, and
some will simply say that some parts of
the equipment should not be cleaned! It
is true that in some cases, for example,
electronics may not be washed down or
exposed to cleaning chemicals; if they
can become soiled, they can be wiped
down with an alcohol-based sanitizer.
Be curious. If a part is attached to
another, detach it; see what is on the
other side. Keep looking until you are
certain that no harborage point remains.
How Often Should Each Piece
of Equipment Be Periodically
This is the million-dollar question.
There is no simple answer other than
“it depends.…” Appropriate PEC fre-
quency is product, process and equip-
ment dependent. Some of the factors to
• If pathogens will die off in your
products, it may not be necessary to
perform periodic cleaning as often
as for product supporting the growth
of pathogenic or spoilage organisms.
If your product can support the
growth of spoilage microorganisms
or pathogens that can form biofilms
in niches and contaminate the prod-
uct, the PEC frequency needs to be
• The design of the equipment and
accessibility during routine cleaning
and inspection of all parts will influence the PEC frequency.
• Older equipment tends to have more
niches that require a more frequent
• Swab results and visual inspection of
adjacent surfaces should also be used
as indicators that a niche needs to be
cleaned more frequently.
Evaluating PEC needs and frequency
is certainly a good exercise for a multi-functional team that would involve
maintenance, sanitation, quality, etc.
Maintenance often disassembles the
equipment for repairs or preventive
maintenance activities. Their observations during such activities can be a
good starting point to establish a frequency. If maintenance and/or sanitors
complain about a bad smell every time
they disassemble a part, then that is a
good indicator of the need to increase
the disassembly and cleaning frequency.
Or if the equipment is visually dirty
when disassembled, then it is probably
because cleaning is not thorough and
the frequency is too low. From there, a
more frequent PEC can be established.
We often suggest performing the PEC
task monthly until a baseline can be
As the equipment is disassembled,
swabs should be taken for indicators
or pathogens. We recommend at least
one quantitative indicator. After cleaning, the equipment is swabbed again.
The precleaning results will provide the
necessary data to establish the PEC frequency of each piece of equipment. As
long as the precleaning results are out of
specification, then the period between
PECs needs to be reduced until the
frequency is adjusted to demonstrate
“Most equipment is
not designed to easily
clean all product and