Comparative Evaluation of Enterotoxigenic Bacteria in Kunu and Zobo Drinks

Introduction: Kunu and zobo are popular non–alcoholic drinks marketed all over Nigeria. They are made from grains and calyx of hibiscus and they are marketed in offices, schools, motor, and parks, and used in festive celebrations. Aim: This study aimed to isolate and identify bacteria associated with kunu and zobo contamination, identify potentially pathogenic strains, and determine the enterotoxin production abilities of some bacteria strains. Methodology: A total of 150 bottles each of kunu and zobo were purchased and examined. Out of the 150 bottles of kunu and zobo, 50 each was purchased from Yenegoa, Sagbama, and Ogbia respectively. Each bottle of the beverage was mixed by gentle inversion several times and 1 ml of it was pipette and added to an ml of peptone water. Subsequent serial dilutions were made to 10⁵ for kunu and 10 for zobo and 0.1 ml of each was cultured on an agar plate in duplicate. The plates were incubated at 37^o C for 18–24 hrs and examined for growth. Results: The percentage occurrences of rod-shaped bacteria isolated from kunu were E. coli 150(27.8%), Salmonella sp. isolated from zobo were 90(18.6%), while Bacillus sp. isolated from kunu were 150(27.8%) and from zobo were 150(31.3%). The percentage occurrence of cocci bacteria isolates from kunu were was 150(27.8%) and from zobo 120(25.0%); coagulase-negative 120(25.0%) and isolated from kunu was 90(16.7%) respectively. The percentage of enterotoxins-producing isolated from was 19(12.7%), while the percentages of S. aureus producing enterotoxins from kunu was 25(16.7%) and from zobo was 18(15.0%) respectively. The counts of bacteria in refrigerated kunu were 7.5 x 10⁵ to 8.7 x 10⁵ and at ambient temperature, the counts were 7.5 x 10⁵ to 1.3 x 10⁶ CFU/ml while zobo refrigerated were 1.1 x 10³ to 1.6 x 10³ and at ambient temperature, 1.1 x 10³ to 2.5 x 10³ CFU/ml. Conclusion: The bacteriological quality of kunu and zobo produced in Bayelsa are poor, the keeping quality of both beverages are very poor at ambient temperature such their consumption beyond 24 hrs is at the consumer's risk especially due to the presence of enterotoxin producing E. coli and S. aureus isolated from the beverages.