Prevalence of Listeria monocytogenes in raw bovine milk and milk products from central highlands of Ethiopia

Abstract

Introduction: Listeria monocytogenes is of major significance in human and veterinary medicine. Most human Listeria infections are foodborne and the association of contaminated milk and dairy produce consumption with human listeriosis is noteworthy. In Ethiopia, there is limited data regarding the prevalence of L. monocytogenes in raw bovine milk and dairy products. The aim of this study was, therefore, to determine the prevalence of L. monocytogenes in raw bovine milk and dairy produce. Methodology: A total of 443 milk and milk product samples were microbiologically analyzed following methods recommended by the U.S. Food and Drug Administration Bacteriological Analytical Manual to isolate Listeria spp. Results: The overall prevalence of Listeria spp. was 28.4% and specifically that of L. monocytogenes was 5.6%. Taking the prevalence of Listeria spp. into consideration, cheese was found to be highly contaminated at 60%, followed by pasteurized milk samples (40%), raw milk (18.9%) and yoghurt (5%). Considering the prevalence of Listeria monocytogenes only, raw milk had the lowest contamination while cheese had the highest, followed by pasteurized milk and yoghurt. Conclusions: Raw milk and milk products produced in urban and peri-urban areas of central Ethiopia were contaminated with pathogenic bacteria, L. monocytogenes. The detection of this pathogen in raw milk and milk products warrants an urgent regulatory mechanism to be put in place and also the potential role of milk processing plants in the contamination of dairy products should be investigated.

Review of common causes of abortion in dairy cattle in Ethiopia

“…Study conducted by Seyoum et al (2015) showed that prevalence of Listeria species was 28.4% and specifically that of L. monocytogenes was 5.6% from raw bovine milk and milk products from central highlands of Ethiopia. Other study conducted in Gondar on foods of animal origin indicated that 25% were positive for Listeria species and that of L. monocytogenes was 6.25% (Garedew et al, 2015) …”

A Review: Prevalence and antimicrobial susceptibility profile of listeria species in milk products

“…On the farm, animals have some pathogens itself, but Listeria is frequently present in manure and fermented silage. Listeria is most abundantly present in the humid areas, stable water including drains, coolers, washing areas and floors (Seyoum et al, 2015). The strong relation between occurrence of L. monocytogenes in raw milk and the infection of the disease frequency was observed.…”

“…However, methods of the transmission for Listeria monocytogenes can include zoonotic, vertical, and nosocomial, it is commonly measured that greatest cases of listeriosis contain food borne transmission. Seyoum et al (2015) studied was carried out that in Ethiopia, data related the occurrence of Listeria monocytogenes is incomplete. In this study presented the occurrence of Listeria spp.…”

“…In conclusion, those studied showed that consuming unpasteurized and raw milk and dairy products are at the risk of listeriosis in humans. Seyoum et al (2015) studied 443 samples of milk and milk product were microbiologically investigated following techniques recommended by the U.S. Food and Drug Administration. The overall occurrence of Listeria species were 28.4% and the positivity of Listeria monocytogenes was 5.6%.…”

Prevalence and Characterization of Listeria Species from Raw Milk and Dairy Products from Çanakkale Province

“…Although pasteurization process destroys L. monocytogenes in raw milk, this process does not eliminate later risk of contamination of dairy products. Also, dairy products may become contaminated with L. monocytogenes during subsequent stages of production (Seyoum et al, 2015). The aim of the present work was to provide information about Listeria spp.…”