Identification of microflora and lactic acid bacteria in pado, a fermented fish product prepared with dried Pangium edule seed and grated coconut

Abstract

Pado is a unique fermented fish product of West Sumatera Indonesia, prepared using dried Pangium edule Reinw seed in combination with grated coconut, with or without salt. Changing of microflora during fermentation has not been extensively reported. This study observed the changes of microflora, especially lactic acid bacteria, during fermentation for 7 days at room temperature (25-30 °C) of pado without the addition of salt. No microorganisms were found on dried P. edule seed. Enterobacteriaceae and spore-forming bacteria decreased and were not found at the end of the fermentation, while the yeast and mold counts were relatively constant at a low level. Instead, lactic acid bacteria increased along with the fermentation process, in line with the decreasing of pH, water contents, and water activity of the fish product. Apparently, few species of lactic acid bacteria are involved during fermentation, most likely due to the use of P. edule seed (as no salt was used). Partial sequencing based on the 16S rRNA gene showed that Lactobacillus plantarum and Lactobacillus pentosus were consistently identified at the various fermentation steps. This study reports that although lactic acid bacteria predominate, only a few species are involved in pado fermentation.