Microbiological Properties of Probioticated Kununzaki Drink Enriched with Cocoa Powder

Abstract

Kununzaki- a popular and an affordable West African cereal-based beverage was enriched with cocoa powder and subjected to ‘probiotication’ with ‘probiotic’ lactic acid bacteria and subsequently investigated for sustained viability of the microbes and ability to suppress growth of food-borne bacteria. This study enumerated the different microbes in enriched kununzaki drink before and during storage, identified the isolated microbes and assessed the viability of the ‘probiotic’ lactic acid bacteria (LABs) in the drink and determined the antagonistic effect of the LABs on two selected food-borne pathogens. This was with a view to enhancing the health giving attributes of affordable kununzaki, which is already a popular beverage in Nigeria. Laboratory results revealed total viable bacteria, lactic acid bacteria and mould counts to range from 4.69 – 8.76, 6.45 – 9.74 and 6.04 – 8.77 log cfu ml-1, respectively. The microorganisms isolated were identified as: Bacillus brevis, B. Badius, B. polymyxa, B. macquariensis, B. pantothenticus, Staphylococcus aureus, S. epidermidis, Serratia marcescens, Lactobacillus delbrueckii, L. fermentum, L. plantarum, L. casei, Aspergillus niger, and Curvularia affinis. ‘Probiotic’ lactic acid bacteria were viable (69.75 log cfu ml-1) at the end of four weeks of storage. The viabilities of Lactobacillus fermentum which were 9.75 and 9.58 log cfu ml-1 at ambient and refrigerated temperatures, respectively were higher than those of other lactic acid bacteria species. The same organism was found to be active against one of the tested food-borne pathogens, Escherichia coli as evident in the diameter of zone of inhibition on plate and broth culture analyses. The study concluded that Lactobacillus fermentum could be effectively used for ‘probiotication’ of kununzaki enriched with 20% cocoa powder and the resulting product exhibited potential of checkmating a food-borne bacterial strain and by implication has the potential of promoting the health of consumers. The product was also found to be microbiologically stable for 4 weeks of storage at ambient and refrigeration temperatures.