Abstract:
This study aimed to investigate the microbiological quality of various fermented dairy
products by isolating different pathogenic bacteria and antibiogram study. A total of 50
samples consisting packaged (n=30) and non-packaged (n=20) were aseptically
collected and subjected to microbiological analysis. The samples were cultured on
selective media to isolate and identify pathogenic bacteria based on morphological,
biochemical, microscopic and molecular characteristics and finally antibiogram study
was done for the isolated bacteria. From the study, it was found that the dahi had the
highest titratable acidity, with mean values of 1.003%, while lassi, matha, and burhani
had lower mean values of 0.51%, 0.63%, and 0.65%, respectively. The Total Viable
Count (TVC) of all fermented dairy products ranged from 6 to 8 log CFU/ml, with the
mean Total Coliform Count (TCC) being lowest in packaged dahi and highest in nonpackaged
burhani.
Furthermore, the Total Salmonella-Shigella Count (TSS) and Total
Staphylococcal Count (TSC) is remarkable in non-packaged burhani and non-packaged
dahi. Out of the 50 samples in total, 52% contained Escherichia coli, 10% had
Staphylococcus, and 4% showed the presence of Salmonella species. In the current
research, it was discovered that 52% of the samples contained at least one type of
bacteria from three different genera: Staphylococcus, Escherichia coli, and Salmonella.
The overall prevalence rate was lower in packaged products (30%) than non-packaged
(85%) products. Almost all of the isolated bacteria were resistant to amoxicillin,
tetracycline and erythromycin exhibiting less resistance pattern to ciprofloxacin,
gentamicin and neomycin. This study revealed that in spite of having high acidity,
fermented dairy products sold at different markets in Dhaka city were contaminated
with multiple species of antibiotic resistant bacteria.
Keywords: Characterization, pathogenic bacteria, fermentation, antibiogram, dairy
products,
