Food Protection Trends - September/October 2020 - 324

TABLE 2. Deli characteristics, samples, and Listeria monocytogenes results
Characteristic

n (of 385 samples)

(%)

286
99
385

74.3
25.7
100.0

45
67
19
50
14
139
43
5
3
385

11.7
17.4
4.9
13.0
3.6
36.1
11.2
1.3
0.8
100.0

382
3
385

99.2
0.8
100.0

Deli size
Small
Large
Total
Sample location
Cutting board/prep table
Deli case
Magnetic board
Meat scale
Reach in cooler
Slicer
Walk-in cooler
Knife hilt
Rolling carts or racks
Total
Confirmed Listeria monocytogenes results
Negative
Positive
Total

performed to compare the percentage of adherence of each
eight recommendations between small and large retail
delis. Analysis was also done on the basis of location of
the delis: rural versus urban. Rural areas were defined as
having a population less than 50,000, and urban areas were
defined as having a population of 50,000 people or more
(44). Frequency statistics and t-tests were performed to
compare the percentage of adherence to each of the eight
recommendations between retail delis located in rural and
urban areas.
RESULTS
Microbial results
In the final data collection activity, a total of 385 microbial
samples were collected in selected Iowa retail deli operations
(Table 2). We collected 286 (74.3%) of 385 microbial
samples in small deli operations, and 99 (25.7%) of 385
samples were collected in large deli operations. These samples
were taken from food contact surfaces or surfaces adjacent
to food contact surfaces (zones 1 or 2) in the operations,
including slicer (n = 139, 36.1%), deli case (n = 67, 17.4%),
and meat scale (n = 50, 13.0%). Of the total microbial
samples (n = 385), only three (0.8%) samples were positive

324

Food Protection Trends September/October

for L. monocytogenes and one sample was positive for L.
welshimeri. Of these three positive L. monocytogenes samples
(Table 3), one sample was located within a large operation
(meat slicer control) and two samples in two different small
operations (interior surface of the deli case samples and meat
slicer table).
A corrective action sampling assignment was conducted
at all small retail delis that had a confirmed positive for
Listeria monocytogenes or Listeria species. Listeria species
detection is often used by the food industry as an indication
that conditions may exist for the presence and growth of
L. monocytogenes (31). In addition, the regulatory agency
performed corrective action samples because smaller
operations may not have the resources to conduct a full
environmental sampling of the deli area. The regulatory
agency collected between 30 and 40 samples at three
operations that were previously sampled during the final
sample assignment. The sample collection was conducted
with a complete sample team of three inspectors (scribe,
sampler, and helper). Another difference between this
corrective action sampling and the final sampling was the
sampling zones. During the final data collection, all samples
were predominately collected in zone 1. The corrective action
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