Rapid identification of bacterial isolates from aqueous kava (Piper methysticum) extracts by polymerase chain reaction and DNA sequencing

Aim: Fresh kava beverages have a limited shelf life under refrigerated conditions. The objective of this study was to isolate and identify bacteria in aqueous extracts of kava rhizome. Methods and Results: The internal part of kava rhizome was used to minimize soil contamination. Three kava extracts were prepared, serially diluted and plated on nutrient agar. Isolated colonies were identified by sequencing polymerase chain reaction amplicons targeting the eubacterial 16S rDNA and the tuf gene of Staphylococcus. Seventy-five bacterial isolates belonged to 16 genera. Bacillus, Cellulomonas, Enterococcus, Pectobacterium and Staphylococcus were identified in all kava extracts. Conclusions: Kava rhizome contains large amounts of starch and fibre, which justify the presence of polysaccharide-degrading bacteria in the extracts. Bacillus cereus group and Staphylococcus species may produce toxins and cause foodborne illness. Significance and Impact of the Study: The results of this study provide fundamental information that may be used to enhance the microbial quality and safety of kava beverages.