Food Protection Trends - September/October 2022 - 386

entered the high hygiene area since the last cleaning
program was undertaken. To facilitate this task, all
surfaces that could harbor Listeria must be accessible to
cleaning fluids, and all equipment should be periodically
dismantled to ensure all surfaces are accessed. The
cleaning program should be scheduled so that Listeria
is actively decontaminated or flushed from the food
processing environment rather than being moved from
one surface to another (e.g., from the floor to food-contact
surfaces) by the cleaning sprays.
* Point 5: Provide an environmental monitoring and
microbiological verification sampling program that
monitors and verifies Listeria control procedures (for
barriers, sources, vectors, and cleaning and disinfection
programs) and maximizes early detection of Listeria in the
production environment to facilitate immediate control.
Whereas there is undoubtedly a matrix of responsibilities
to effectively control Listeria, Fig. 1 indicates that the primary
responsibilities are for senior management to coordinate
the 5-point plan, for the technical department to establish
and manage the barriers and environmental sampling plan,
for engineering to hygienically specify and maintain the
manufacturing infrastructure, for production to coordinate
all manufacturing activities to manage potential crosscontamination
vectors, and for the cleaning or sanitation
department (hygiene) to establish and manage the cleaning
and disinfection programs. Effective Listeria control can,
thus, only be ensured if it is managed by a dedicated team,
encompassing, at a minimum, senior management and these
four departments.
Elements of the 5-point plan should already be established
in RTE food factories as part of existing GMPs, though no
attempt has currently been made to bring these elements
together into a cohesive plan. Barriers to control Listeria
entrance to the high hygiene area (point 1) should be well
established, validated, monitored, and verified and could
include the following:
* Food products: decontamination treatments (e.g.,
cooking, frying, washing).
* Other ingredients and rework: surface decontamination
treatments (disinfectant spray and UV tunnels).
* Packaging materials: double bagging or manual surface
decontamination.
* Operatives: personal hygiene practices, changing room
procedures, boot washing.
* Air: filtration, air changes per hour, directional air
movements.
* Items such as manufacturing utensils, transport systems,
maintenance equipment, quality control sampling and
measurement devices, and cleaning chemical containers:
cleaning and decontamination procedures.
* Waste: solid and liquid waste management systems.
Similarly, cleaning and disinfection programs designed to
control Listeria (point 4) should also be well established, vali386
Food Protection Trends September/October
dated, monitored, and verified (9). Cleaning and disinfection
programs include the following:
* Interim cleans to control cross-contamination between
product stock-keeping units during production.
* End-of-production cleans to control cross-contamination
between production days or batches.
* Periodic cleans in which equipment or building fabrics are
further dismantled to expose poor hygienically designed
features for cleaning, which could have harbored Listeria.
Inaccessible harborage sites (Listeria sources) can in some
instances be treated by dry heat (placing items in ovens)
or steam.
* Decontamination or " firebreak " cleans, which seek to
decontaminate the whole of the high hygiene production
area, equipment, and utensils following a Listeria
contamination incident.
An environmental monitoring and microbiological
verification sampling program (point 5) will also be in place,
though its objectives and focus may not be clear (addressed
later in the text and in Fig. 4).
However, what is less likely to be in place is a systematic
assessment of the food processing environment and production
practices for potential Listeria sources and product vectors
(5-point control plan, points 2 and 3), termed a processing
environmental plan (PEP) (13, 15). In practice, this can be
undertaken as a complementary step to the HACCP study; the
HACCP study considers the risks of Listeria at each of the processing
steps, whereas the PEP considers the generic Listeria
risks within the processing environment.
In the PEP, prerequisites are developed to control identified
sources or vectors of Listeria contamination, and those that are
deemed critical to food safety can be raised to the level of operational
prerequisites (OPs) (16), which can be then managed
in the same way as CCPs (CCPs manage the product and process,
OPs manage the processing environment). This concept
has been recognized in U.S. legislation under the Food Safety
Modernization Act, in which controls critical to managing
food safety are known as " preventative controls. " Preventative
controls can include HACCPs and CCPs, but they also include
traditional prerequisites, e.g., sanitation, allergen, and supply
chain controls (20). The following sections on the PEP (points
3 and 4) and the environmental sampling plan (point 5)
provide further information on these points and how they are
combined and developed to form an effective Listeria control
plan via an environmental sampling plan journey.
PEP
The undertaking of the PEP follows the 14 steps of the HACCP
plan as defined by Gaze (12) such that the same food safety
management principles are used in addressing hazards in both
the food process (HACCP) and processing environment (PEP).
Step 1. Obtain management commitment. Senior management
must be committed to providing the necessary resource for
the study to be planned, undertaken, implemented, and periodi
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