environment must be monitored to ver-
ify that the programs are working and
that harborage sites have not developed.
Alternative 3 facilities are required to
have an environmental monitoring pro-
gram in place that includes product con-
tact testing in the post-lethality
Zone 4 areas include hallways, loading
docks, warehouses, coolers, bathrooms,
locker rooms and break rooms.
“The environmental sampling program is critical to
preventing and controlling Listeria in RTE meat
and poultry environments.”
processing areas to ensure that surfaces
are sanitary and free of L. monocytogenes
or its indicator organisms. 3 The monitoring program must include details on the
frequency of testing, size and location of
sample sites and should include an explanation of why the testing frequency is
adequate to ensure that effective control
is maintained.
The establishment should also identify the hold-and-test procedures following a positive result on a product contact
surface. 3 An effective monitoring program will identify the source of contamination, eliminate the microorganism
from the environment and prevent future contamination by ongoing testing
of indicator sites. These indicator sites
are non-product contact sites that “
indicate” the presence of the microorganism
in the processing environment or ancillary areas.
The “zone” concept is widely used in
RTE meat and poultry plants for environmental monitoring programs; plant
operations are divided into zones based
on level of risk. Zone 1 represents product contact surfaces, the highest level of
risk. Zone 2 sites are non-product contact sites that are directly adjacent to
product contact surfaces and can include
control buttons, equipment framework
and mechanics’ tools. Zone 3 sites are
within the post-processing areas and include floors, walls, drains, floor mats,
forklifts, pallets and air handling units.
Zone 4 sites are not in the post-processing areas, but if unchecked, can lead to
cross-contamination of Zones 1, 2 and 3.
and eliminate growth niches. For a processing facility that is in control, sampling and testing focus can move into
Zones 2, 3 and 4. Successful processors
focus on prevention of contamination
by focusing their sampling efforts on indicator sites and then reacting to all positive results, at both product contact and
indicator sites, quickly and effectively.
Note that Zone 1, or product contact
testing, is a requirement for Alternative 3
processors and must be included in the
sampling program.
The environmental sampling program is critical to preventing and controlling Listeria in RTE meat and poultry
environments. The goal of this program
is to find the microorganism. However,
ongoing monitoring of the environment
would be useless if no efforts were in
place to fix the problem once identified.
Every successful sampling program must
include a corrective action plan to define
how the processor will respond to a positive finding. These corrective actions
should identify and control the source
of the contamination, thereby preventing future contamination.
Intervention Strategies
RTE meat and poultry processors rely
on numerous interventions for control-
ling the transfer, development of niches,
and growth of Listeria in the manufactur-
ing environment. Industry sharing of
best practices and lessons learned has
been a key component of the success of
this food industry segment. Meat proces-
sors have agreed that food safety infor-
mation should be shared on a non-com-
petitive basis and are willing to share
best practices for strategies that work in
their facilities through Listeria work-
shops. Although many of these strategies
have not been validated in a laboratory
setting, processors routinely utilize them
and have demonstrated success with re-
gard to Listeria control.
