The overall prevalence of Listeria species in meat samples was found to be 29% that indicated significant public health risk associated with consumption of meat. The findings of this study is consistent with the study done in Addis Ababa and Gondar where the prevalence of Listeria species was 27.5% and 26% respectively [15, 28]. However, the present study was higher than the 14% occurrence reported in Jimma town  and 12% occurrence in Addis Ababa . The variation in detection of Listeria species in foods in different studies could be attributable to the difference in sample type, samples sizes, variations in meat handling and hygienic practices of meat handlers.
In the present study, the predominant identified Listeria species was L. innocua (14, 48%), L. seeligeri (8, 28%), L. welshimeri (3, 10%), L. monocytogenes (2, 7%) and L. grayib (2, 7%). In this study, bacteriological examinations showed that raw bovine meat was found contaminated with Listeria species in both abattoir and butcher shops. This might be due to raw bovine samples were exposed to contaminants during slaughtering, processing and retailing. This finding is in agreement with report of .
In this study, L.monocytogenes isolates were found to be resistant to cloxacillin, tetracycline, nalidixic acid penicillin. This finding is in agreement with the previous report of [16, 17, 31, 32, 33]. This may be attributed to the indiscriminate use of these antimicrobial agents in food producing animals at sub-therapeutic levels or prophylactic doses resulted in the emergence of antimicrobial-resistant strains to certain antimicrobials [16, 20, 33, 34]. In developing countries there is a wide spread and uncontrolled usage of this antimicrobials due to its relatively cheaper price and easily accessibility. Penicillin and tetracycline are one of the most frequently prescribed drugs for most of infectious diseases in veterinary medicine that could be mentioned as one of the reasons for the development of increased resistance profile [16, 35, 36]. Therefore, such antimicrobial resistant L. monocytogenes isolates in raw meat products has an important public health implication. In contrary, L. monocytogenes isolates had showed high susceptibility to gentamicin, vancomycin, sulfamethoxazole, chloramphenicol and cloxacillin which is in agreement with previous studies [6, 16, 37].
In this study, the butcher shop and abattoir workers who had a low level of education (1–4) were statistically associated with Listeria meat contamination 32.78% (95% CI: 21.5–46.2%; P < 0.05). This finding is in agreement with the report of [38, 39]. Studies have shown that butcher shop and abattoir workers who had low level of education were not adhering with strict hygienic practices and standard slaughtering practices which lead to microbial contamination of meat [40, 41].
Likewise, meat samples examined from butcher shops and abattoir workers who did not attend any training regarding meat hygiene and handling practices were statistically associated with contamination of meat by Listeria 39.3% (95% CI: 28.1–51.9%; P < 0.05). Several reports showed that, the workers working in the abattoir and butcher shops in most cases in developing countries are untrained and thus, they pay no attention to the hygienic standards and as result contribute immensely to bacterial contamination . Therefore, food safety training of meat handlers about the basic concept and requirements of personal hygiene and its environment plays an important part in safeguarding the quality of meat products [42, 44, 45].
In this study, the use of unclean equipment in butcher shops and abattoir was statistically associated with Listeria meat contamination 37.5% (95% CI: 26.05–50.6%; P < 0.05). This finding is in agreement with other findings [46, 47]. This could be due to numerous cross-contamination risks exist in primary food production systems especially at the point lairage, slaughter processes and post-harvest handling due to unclean knives, working surface and utensils .
Conclusion: The overall proportion of Listeria positive samples from raw bovine meat in this study was 29% (95% CI: 21.0-38.5%). Out of these, 15 (30%, 95% CI: 34.4–68.6%) and 14 (28%, 95% CI: 31.4–65.6%) were isolated in the samples collected from butcher shops and abattoir of Jimma town respectively. The dominant Listeria species isolated was L. innocua (48%). The presence of Listeria species both in the abattoir and butcher shops of Jimma town have been attributed to unhygienic meat handling practices. This turn influenced by lack of on job training and use of unhygienic equipments and meat contact surfaces. Therefore, there is a need for periodic training on hygienic meat handling practices for meat handlers at each stage of meat production chain.