Physicochemical and Bacteriological Assessment of Traditional Sorghum Beers in Jimeta, Nigeria

Abstract

Sorghum beer popularly known as “burukutu” in Nigeria is a traditional beverage whose consumption has been passed down through generations. This beer, consumed while actively fermenting, harbors a diverse array of microorganisms. This study aims to evaluate the bacteriological and physicochemical characteristics of traditional sorghum beers sold in Jimeta, Adamawa State, Nigeria. Beer samples were obtained from eight traditional beer joints within the Jimeta metropolis, Adamawa State, Nigeria. The physicochemical analysis of the samples revealed titratable acidity ranging from 0.91% to 2.65%, pH values from 4.20 to 4.50, total reducing sugars from 10.1 mg/mL to 15.0 mg/mL, ethanol content from 3.12% to 4.69%, and total solids from 6.50 mg/mL to 7.60 mg/mL. The total bacterial count, determined using aerobic plate count, ranged from 8.0 × 10² to 1.0 × 1010 CFU/mL. Pure cultures from each sample were identified through cultural characteristics, Gram staining, motility, and biochemical tests including citrate utilization, catalase, indole, urease, methyl red, Voges-Proskauer and coagulase. Total of 44 isolates were identified, with Staphylococcus aureus and Streptococcus sp. being the most prevalent (8 isolates), followed by Escherichia coli and Pseudomonas aeruginosa (6 isolates), Klebsiella pneumoniae and Acinetobacter sp. (4 isolates), and Bacillus subtilis, Bacillus cereus, Serratia sp. and Proteus mirabilis (2 isolates). The presence of these potential pathogens raises great concerns about the safety of these beers. Improved sanitary practices during production, handling and serving are necessary to ensure consumer safety.