Abstract:
Background: Milk consumption plays a great role in the nutrition for consumers and an income
of producers as well as vendors, but their bacteriological quality causes loss of those benefits.
There is no previous study conducted on bacteriological quality, its associated factors and
antimicrobial susceptibility pattern of bacterial isolates from raw milk of Gomole district,
therefore the magnitude of the problem not known.
Objective: The aim of this study was to determine the bacteriological quality of raw milk, its
associated factors and antimicrobial susceptibility pattern of bacterial isolates of milk collected
from producers and vendors in Gomole district, Borena zone, South Ethiopia from March 1 to
April 30, 2019.
Methods: A cross sectional study was conducted on 132 purposively selected study participants.
A pretested questionnaires and observations were used to collect data on factors associated with
milk quality. Then, 15 to 20mL of milk samples were collected from producers and vendors for
laboratory analysis. Milk samples were serially diluted and inoculated on Nutrient Agar and
Eosin Methylene Blue Agar for total bacteria count and total coliforms count respectively.
Further bacterial isolation by culture and antimicrobial susceptibility test using Kirby Bauer’s
disk diffusion method was made from those milk samples reported as poor bacterial quality by
total bacterial count. Data was entered by EPI data version 3.1 and using software SPSS version
21 analyzed descriptive statistics and chi-square (χ
2
) for association factors.
Results: The overall means± standard deviation of total bacteria and coliforms were 7.75±0.882
and 6.69±1.545 log10 CFU/mL respectively. Escherichia coli (30.8%), Staphylococcus aureus
(17.9%) and Salmonella spp (2.6%) were isolated from milk samples identified as poor quality.
All Escherichia coli isolates were 100% susceptible to gentamycin, ciprofloxacin and
chloramphenicol. The overall multi drug resistant was 12.5%.
Conclusion: The overall proportions of poor quality of milk samples by total bacterial and total
coliform count were 90% and 80%, respectively. The factors significantly associated with poor
milk quality were hand wash practices before milking, source of water for cleaning and
cleanliness of milk containers.
Recommendation: The producers and vendors should focus on the hygienic measures to
improve the bacteriological safety of raw milk
