Bacteriological quality and public health risk of raw milk in Ethiopia: a systematic review

Abstract

Foodborne diseases remain a major public health problem worldwide, particularly in developing countries. The consumption of raw milk poses significant public health risks due to potential contamination with pathogenic bacteria. The objective of the present review was to determine the bacteriological load of raw milk and estimate the prevalence of bacterial pathogens associated with public health risk in Ethiopia. A total of 62 previous studies were included in the analysis from PubMed, Research Gate and Google Scholar databases following the PRISMA guidelines. The mean total bacterial count of raw milk from 32 previous studies was computed to be 6.46 log10 cfu/mL whereas the total coliform count was estimated to be 4.64 log10 cfu/mL. The maximum and minimum loads for the total bacterial count were between 9.00 and 4.51 log10 cfu/mL respectively. The total coliform count ranged from 2.89 to 8.78 log10 cfu/mL. The prevalence rates of the 30 studies analyzed for E.coli O157:H7, S. aureus, Salmonella spps and L. monocytogens were determined to be 6.19%, 21.42%, 12.79% and 10.74% respectively. The prevalence rate of E.coli O157:H7 in the collected milk samples ranged from 0.20 to 36.63% whereas that of S. aureus ranged from 8.64 to 55.14%. The prevalence rates of Salmonella spp. and L. monocytogens ranged from 8.50 to 28.57% and 2.60–20.00%, respectively. The majority of the studies analyzed (86.67%) for prevalence estimation employed conventional culture methods and biochemical tests for the identification of bacterial pathogens in raw milk. The mean bacterial load was above the Ethiopian standard authority and European Union guideline set for the bacteriological quality of raw milk. Strengthening milk safety policies, promoting pasteurization, and educating producers and consumers are critical for reducing health risks while preserving cultural practices.