Abstract
Milk and milk products play an important role in the diet of pastoralists in Ethiopia. However, only few studies have been conducted on the microbial contamination of milk and milk products in pastoral areas. Therefore, the objective of the present study was to assess the hygiene and safety of ready-to-consume milk and traditionally produced fermented milk products (yogurt) in Borana. A total of 203 raw milk and milk product samples collected from different points along the milk production and handling chains were tested for Escherichia coli, E. coli O157:H7, and Staphylococcus aureus. E. coli was detected in 51.7% of the analyzed samples with a mean count of 2.5 logCFU/ml. The study revealed that 10.8% and 2.5% of the milk and dairy product samples harbor S. aureus and E. coli O157:H7, respectively. Detection of E. coli O157:H7 in ready-to-consume milk has potential health implications for consumers in an area where raw milk consumption is common. To our knowledge, this is the first report of the isolation of E. coli O157:H7 from milk in pastoral systems in Ethiopia.
This is a preview of subscription content, access via your institution.

Data Availability
All the data pertaining to the manuscript can be obtained from the corresponding authors upon request.
References
Amenu, K., Szonyi, B., Grace, D. and Wieland, B., 2017. Important knowledge gaps among pastoralists on causes and treatment of udder health problems in livestock in southern Ethiopia: Results of qualitative investigation BMC Veterinary Research, 13
Amenu, K., Wieland, B., Szonyi, B. and Grace, D., 2019. Milk handling practices and consumption behavior among Borana pastoralists in southern Ethiopia Journal of Health, Population and Nutrition, 38
Argudín, M.Á., Mendoza, M.C. and Rodicio, M.R., 2010. Food poisoning and Staphylococcus aureus. Enterotoxins Toxins. https://doi.org/10.3390/toxins2071751
Ayele, Y., Gutema, F.D., Edao, B.M., Girma, R., Tufa, T.B., Beyene, T.J., Tadesse, F., Geloye, M. and Beyi, A.F., 2017. Assessment of Staphylococcus aureus along milk value chain and its public health importance in Sebeta, central Oromia, Ethiopia BMC Microbiology. https://doi.org/10.1186/s12866-017-1048-9
Bennett, R. and Lancette, G., 2001. Bacteriological Analytical Manual Chapter 12 Staphylococcus aureus In: Bacteriological Analytical Manual,
Birhanu, M., Leta, S., Mamo, G., Tesfaye, S. 2017. Prevalence of bovine subclinical mastitis and isolation of its major causes in Bishoftu Town, Ethiopia. BMC Research Notes 10 (1):767
Chye, F.Y., Abdullah, A. and Ayob, M.K., 2004. Bacteriological quality and safety of raw milk in Malaysia Food Microbiology. https://doi.org/10.1016/j.fm.2003.11.007
Coppock, D.L. (ed), 1994. The Borana plateau of southern Ethiopia: synthesis of pastoral research, development, and change, 1980-91, (ILRI (aka ILCA and ILRAD): Nairobi)
Disassa, N., Sibhat, B., Mengistu, S., Muktar, Y. and Belina, D., 2017. Prevalence and Antimicrobial Susceptibility Pattern of E. coli O157:H7 Isolated from Traditionally Marketed Raw Cow Milk in and around Asosa Town, Western Ethiopia Veterinary Medicine International. https://doi.org/10.1155/2017/7581531
Doǧan-Halkman, H.B., Çakir, I., Keven, F., Worobo, R.W. and Halkman, A.K., 2003. Relationship among fecal coliforms and Escherichia coli in various foods European Food Research and Technology. https://doi.org/10.1007/s00217-002-0647-2
Eguale, T., Engidawork, E., Gebreyes, W.A., Asrat, D., Alemayehu, H., Medhin, G., Johnson, R.P. and Gunn, J.S., 2016. Fecal prevalence, serotype distribution and antimicrobial resistance of Salmonellae in dairy cattle in central Ethiopia BMC Microbiology. https://doi.org/10.1186/s12866-016-0638-2
Ennani, B. and Hidane, K., 2004. Antimicrobial activity of camel ’ s milk against pathogenic strains of Escherichia coli and Listeria monocytogenes International Journal Of Dairy Technology
Garbaj, A.M., Awad, E.M., Azwai, S.M., Abolghait, S.K., Naas, H.T., Moawad, A.A., Gammoudi, F.T., Barbieri, I. and Eldaghayes, I.M., 2016. Enterohemorrhagic Escherichia coli O157 in milk and dairy products from Libya: Isolation and molecular identification by partial sequencing of 16S rDNA Veterinary World. https://doi.org/10.14202/vetworld.2016.1184-1189
Garedew, L., Mengesha, D., Birhanu, A. and Mohammed, A., 2015. Diverse gram-positive bacteria identified from raw and pasteurized cow milk consumed at Gondar town and its environs, Ethiopia. Ethiopian Veterinary Journal, 19, 49–61
Griffiths, M.W., 2010. Improving the safety and quality of milk: Milk production and processing (Woodhead Publishing Limited)
Gutiérrez, D., Delgado, S., Vázquez-Sánchez, D., Martínez, B., Cabo, M.L., Rodríguez, A., Herrera, J.J. and García, P., 2012. Incidence of staphylococcus aureus and analysis of associated bacterial communities on food industry surfaces Applied and Environmental Microbiology. https://doi.org/10.1128/AEM.02045-12
Gyles, C.L., 2007. Shiga toxin-producing Escherichia coli: an overview. Journal of Animal Science. https://doi.org/10.2527/jas.2006-508
LeJeune, J.T. and Rajala-Schultz, P.J., 2009. Unpasteurized Milk: A Continued Public Health Threat Clinical Infectious Diseases, 48, 93–100
Lingbeck, J.M., Cordero, P., O’Bryan, C.A., Johnson, M.G., Ricke, S.C. and Crandall, P.G., 2014. Functionality of liquid smoke as an all-natural antimicrobial in food preservation
Millogo, V., Svennersten Sjaunja, K., Ouédraogo, G.A. and Agenäs, S., 2010. Raw milk hygiene at farms, processing units and local markets in Burkina Faso Food Control, 21, 1070–1074
Muir, D.D., 1996. The shelf-life of dairy products: 1. Factors influencing raw milk and fresh products International Journal of Dairy Technology. https://doi.org/10.1111/j.1471-0307.1996.tb02616.x
Oliver, S.P., Boor, K.J., Murphy, S.C. and Murinda, S.E., 2009. Food safety hazards associated with consumption of raw milk Foodborne Pathog Dis, 6, 793–806
Regassa, A., Golicha, G., Tesfaye, D., Abunna, F., Megersa, B. 2013. Prevalence, risk factors, and major bacterial causes of camel mastitis in Borana Zone, Oromia Regional State, Ethiopia. Tropical Animal Health and Production 45 (7):1589–1595
Stephen D. Weagant (ret.), K.J.P.F., 2011. Laboratory Methods - BAM: Diarrheagenic Escherichia coli
Thomas, D.E. and Elliott, E.J., 2013. Interventions for preventing diarrhea-associated hemolytic uremic syndrome: Systematic review BMC Public Health. https://doi.org/10.1186/1471-2458-13-799
Tigabu, E., Asrat, D., Kassa, T., Sinmegn, T., Molla, B. and Gebreyes, W., 2015. Assessment of Risk Factors in Milk Contamination with Staphylococcus aureus in Urban and Peri-Urban Small-Holder Dairy Farming in Central Ethiopia Zoonoses and Public Health, 62, 637–643
Tong, S.Y.C., Davis, J.S., Eichenberger, E., Holland, T.L. and Fowler, V.G., 2015. Staphylococcus aureus infections: Epidemiology, pathophysiology, clinical manifestations, and management Clinical Microbiology Reviews. https://doi.org/10.1128/CMR.00134-14
Wanjala, N.W., Matofari, J.W. and Nduko, J.M., 2016. Antimicrobial effect of smoking milk handling containers’ inner surfaces as a preservation method in pastoral systems in Kenya Pastoralism, 6. https://doi.org/10.1186/s13570-016-0064-y
Acknowledgments
Sample collection and laboratory analysis were undertaken when Kebede Amenu and Shemsu Nemo were affiliated with Hawassa University and we thank the University for the provision of laboratory space for the microbiological analysis.
Funding
This study was initially supported through the CGIAR Research Program (CRP) on Livestock and Fish and since 2017 through CRP Livestock. Kebede Amenu was supported through DAAD (German Academic Exchange Service) Fellowship.
Author information
Authors and Affiliations
Contributions
KA: conceived the research idea, wrote the protocol, supervised lab works, performed data analysis and drafted the initial manuscript, and revised the manuscript
SN: involved in proposal write-up, microbiological analysis, and manuscript preparation
BW, DG: supervised the research and made substantial intellectual contribution in the designing of the study, preparation of the study protocols; result interpretation and manuscript preparation. All authors read and approved the final manuscript.
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that there are no competing interests.
Ethics approval and consent to participate
The research protocol for this study has been approved by the Ethics Committee of the College of Veterinary Medicine and Agriculture of Addis Ababa University for milk sample collection from individual animals.
Consent for publication
The authors declare that the manuscript does not contain any personally identifiable information.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Amenu, K., Grace, D., Nemo, S. et al. Bacteriological quality and safety of ready-to-consume milk and naturally fermented milk in Borana pastoral area, southern Ethiopia. Trop Anim Health Prod 51, 2079–2084 (2019). https://doi.org/10.1007/s11250-019-01872-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11250-019-01872-8
Keywords
- Escherichia coli O157:H7
- Staphylococcus aureus
- Milk contamination
- Microbiological safety
- Borana
- Ethiopia