Food Protection Trends - May/June 2020 - 206

As noted by several speakers, some of the confusion related
to the use of microbiological testing for verification of preventive controls stems from misunderstanding the difference between "verification" and "validation." Pamela Wilger (Cargill)
reminded the audience that validation asks, "Will it work?"
while verification asks, "Is it working?" While "validations" are
required only initially and when major changes occur to ensure
that controls within a manufacturing process actually minimize
or prevent a hazard, "verifications" are repeated on a frequent,
regular basis to ensure that the process is being consistently
performed in a way that will minimize or prevent that hazard.
Wilger emphasized that microbiological testing also plays a
critical role in validation if a preventive control seeks to minimize a microbial hazard, and microbiological methods used in
verification activities must be validated for the sample type and
sample size being tested.
Microbiological testing for verification activities
Microbiological testing is important in verification of several
types of preventive controls: to ensure that process controls
are working; to verify that sanitation controls are effective; and
to enable manufacturers and suppliers to share information
regarding the microbiological status of food products or ingredients (supplier controls).
Microbiological testing for verification of process controls
Microbiological testing can be used to verify that a process
used to control a pathogen is working properly on a day-to-day
basis. For example, after washing lettuce, a producer may periodically test for an indicator organism in the washed lettuce
at defined intervals during production to make sure that their
(previously validated) lettuce washing method is consistently
effective in preventing cross-contamination.
End product testing may be useful to verify the effectiveness
of the overall manufacturing process in controlling microbial
hazards, but it should not be relied upon exclusively to ensure
safety or quality of a lot. For example, a hummus manufacturer
may schedule regular Enterobacteriaceae testing of product to
verify that a high-pressure processing (HPP) step consistently
reduces microbial levels. This testing verifies a processing control and isn't being used solely to determine whether that lot of
hummus is acceptable for release.

Microbiological testing for environmental monitoring
and verification of effective sanitation
Environmental monitoring is a form of microbiological
testing that can be used to verify that sanitation controls in
a manufacturing facility are working consistently and effectively. As is true for all types of microbiological testing used
for verification, the goal is to actually find the pathogen or
indicator organism if it is present, not to fear such results.
Deann Akins-Lewenthal (Conagra Brands) told the audience
they should actively seek out positive results, because knowing
where pathogens are is the only way to eliminate them from
a manufacturing facility. A company's sampling plan should
follow this ethos.
Although it is important to focus on sampling areas where
the highest risks occur (such as food contact surfaces in RTE
manufacturing facilities), Akins-Lewenthal also recommended
monitoring low-risk areas to identify microbiological problems
within a facility that could potentially migrate into high risk
areas. Sampling should cover all production days and shifts.
Environmental monitoring data need to be tracked in a way
that allows trends to be identified, whether through the use of
software designed for this purpose or by simply mapping positive results over time onto a diagram of the facility. Having a
new set of eyes periodically conduct a mass swabbing is a good
way to ensure that certain locations are not being routinely
missed during testing.
Microbiological testing for supplier verification
Under the preventive controls rule and the Foreign Supplier
Verification Program rule, manufacturers are required to perform supplier verification activities when hazard analysis has
identified a hazard requiring a preventive control. This means
that when a manufacturer receives an ingredient, it must verify
that hazards associated with that ingredient are controlled. This
can be done in several ways: the supplier could perform regular
microbiological testing on the ingredient, and this information
would be included on a certificate of analysis (COA) for each
lot of the ingredient. The COA then would be reviewed by the
manufacturer before use. The manufacturer should perform
other steps to ensure that the testing performed (or directed by
the supplier) was performed appropriately. Supplier verification of a control for a microbiological hazard could also involve

21 CFR §117.165 Verification of implementation and effectiveness.
(a)(1). Verification activities. You must verify that the preventive controls are consistently implemented and are effectively and
significantly minimizing or preventing the hazards. To do so you must conduct activities that include the following, as
appropriate to the facility, the food, and the nature of the preventive control and its role in the facility's food safety system:
(a)(2). Product testing, for a pathogen (or appropriate indicator organism) or other hazard;
(a)(3). Environmental monitoring, for an environmental pathogen or for an appropriate indicator organism, if contamination of a ready-to-eat food with an environmental pathogen is a hazard requiring a preventive control, by
collecting and testing environmental samples.
Figure 4. Verification related to microbiological testing as required by the preventive controls rule.

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Food Protection Trends May/June

Food Protection Trends - May/June 2020

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