## 4 Discussion  
An effort was made to recover the _Listeria_ spp. present in marine fish and the seafood environment to further characterize the _Listeria monocytogenes_ isolates and identify their possible transmission routes. In this study, the prevalence rate of _Listeria monocytogenes_ in fish samples was 11.5% (95% C.I. = 7.1-17.4%). According to other researchers, the prevalence of _Listeria monocytogenes_ in fish is quite variable. In general, most of the studies report a _Listeria monocytogenes_ prevalence ranging from 5.2% to 39.0%. In a review by [PERSON] [34] dating from 1994, it was reported that _Listeria monocytogenes_ prevalence usually varies from 4% to 12% and is generally lower than that of other food commodities. The results of this study are also in agreement with the results reported by [PERSON] and [PERSON] [15], who detected the bacterium in 15 out of 103 pooled rainbow trout samples (14.6%) that were mostly harvested from sea areas around Finland [34]. Similarly, [PERSON]  
Figure 1: Main spectra dendrogram of _Listeria monocytogenes_ isolates. and [PERSON] [35] isolated the pathogen from 5 out of 48 fish samples (10.4%). Accordingly, in a survey in Poland from 2016 to 2017, [PERSON] and [PERSON] [36] detected the bacterium in 18 of the 102 samples of marine fish (17.6%). [PERSON] et al. [37] determined the occurrence of _Listeria monocytogenes_ in fish markets located in China and reported that among 109 fresh fish samples, 15 (13.8%) were found to be positive for _L. monocytogenes_. [PERSON] et al. [38] collected fresh seafood samples from various fish markets in India and reported a prevalence of approximately 9%. In contrast, [PERSON] et al. [39] reported that 32 out of 85 fish samples (37.6%) tested positive for _L. monocytogenes_, a rate that is higher than that reported in the present study, possibly due to environmental differences and the market types from which the samples were collected. [PERSON] et al. [40] collected samples of freshwater raw fish from fish markets in northern Iran and reported a _Listeria monocytogenes_ prevalence of 7.6%, a rate that is marginally within the 95% C.I. of this study. [PERSON] and [PERSON] [41], also in Iran, reported a lower rate (7.7% of samples positive for _L. monocytogenes_) among 120 marine fish samples collected from supermarkets. [PERSON] et al. [42] reported that all samples of marine fish (n = 37) tested negative for _Listeria_ spp. and subsequently for _L. monocytogenes_, perhaps due to the small number of samples examined. It is interesting that in the study by [PERSON] et al. [43], who examined 120 samples of raw fish from fish shops in the same area as in the present study (Thessaloniki, Northern Greece), only one sample tested positive, resulting in a rate of 0.8%. In the present study, five isolates of _Listeria monocytogenes_ (4.0%, 95% C.I. = 1.3-9.2%) were detected from the fish-processing areas and the sales environment of the fish market. These isolates were recovered from the cutting boards and the ice in which the fish were preserved. Several studies have reported _Listeria monocytogenes_ isolation from similar sites. [PERSON] et al. [44] reported a similar rate of _Listeria monocytogenes_ in environmental samples (17.1%), with samples from the cutting boards and ice being more contaminated (cutting boards: 4/18 positive, 22.0%; ice: 5/12 positive, 28.6%) than the rest of the environmental samples. Similarly, a previous study carried out in Scandinavia by [PERSON] et al. [45] reported a detection rate of the pathogen in ice of 6.7%, a result that is consistent with the results of the present study. Also, [PERSON] et al. [46] reported that the ice samples and the cutting boards collected from U.S. catfish-processing plants were contaminated with _Listeria monocytogenes_ at a rate of 55.6% and 33.0%, respectively, possibly due to the larger prevalence of _Listeria monocytogenes_ in the fish being observed (76.7%). In addition, [PERSON] et al.