Isolation and Characterisation of Lactic Acid Bacteria from Traditionally Fermented Zobo Drink in Katsina State

Zobo drink, prepared from Hibiscus sabdariffa calyces through aqueous extraction and informal fermentation, is widely consumed in northern Nigeria, yet its microbiological composition and safety during fermentation in Katsina State remain undocumented. This study isolates and characterises lactic acid bacteria (LAB) from traditionally fermented zobo samples in Katsina State, North West Nigeria. Twenty zobo samples at different fermentation stages (0, 24, 48, and 72 hours) were collected from roadside vendors in Katsina and Dutsinma. LAB were selectively isolated on De Man, Rogosa, and Sharpe (MRS) agar under anaerobic conditions and characterised by Gram staining, catalase testing, sugar fermentation profiles, and gas production from glucose. Antagonistic activity against Escherichia coli, Salmonella typhi, and Staphylococcus aureus was assessed by agar well diffusion. Lactobacillus plantarum, Lactobacillus fermentum, and Leuconostoc mesenteroides were the dominant LAB species identified. LAB populations increased from 1.2 x 103 to 8.6 x 107 cfu/ml across the fermentation period, coinciding with a pH drop from 5.8 to 3.4. Inhibitory activity against all three test pathogens was confirmed in 78 percent of LAB isolates. The study establishes that spontaneous LAB fermentation in zobo confers natural antimicrobial properties, though contamination risks during prolonged post-fermentation storage warrant attention. Keywords: lactic acid bacteria, zobo drink, Lactobacillus plantarum, fermentation, Katsina State