Microbiological assessment of probioticated ginger‐based beverages

Abstract

PurposeThe need for production of more health‐promoting and affordable drinks prompted the idea of incorporating probiotic bacterial isolates into ginger‐based beverages. The purpose of this paper is to evaluate the viability of two probiotic bacterial isolates (Lactobacillus plantarum and Lactobacillus bulgaricus) in ginger and ginger with garlic beverages and to determine in vitro inhibition of Escherichia coli NCIB 85 and Staphylococcus aureus NCIB 8586 (common food‐borne pathogens) by the probiotic beverages.Design/methodology/approachInoculation of sterilized ginger‐based beverages with isolated Lactobacillus strains was carried out and subsequently stored at ambient temperature (27 ± 1°C) and refrigeration temperature (4 ± 1°C) for four weeks. Lactic acid bacteria count of each probioticated sample was determined at intervals using standard method. In vitro inhibition of the food‐borne pathogens by the probiotic beverages was determined with broth culture method.FindingsResults revealed the log count of Lactobacillus plantarum in the ginger beverage to be from 9.11 to 8.09 and 7.82 cfu/ml at ambient and refrigeration temperatures, respectively, at the fourth week of storage. Log count of Lactobacillus bulgaricus also ranged from 7.68 to 2.25 cfu/ml after four weeks of storage at ambient temperature while it remained at 5.57 cfu/ml after three weeks of storage at refrigeration temperature. L. bulgaricus however, failed to survive beyond three weeks in refrigerated storage. Similar trend of viability was exhibited in ginger with garlic beverage. Probiotic ginger, and ginger with garlic beverages inhibited the growth of E. coli and S. aureus to varying degrees during the period of storage.Originality/valueGinger‐based beverages could therefore be used as carriers of probiotic bacteria and thus serve as health drinks for consumers of different socio‐economic strata.