Potential Probiotic Food from Kalimantan: Haruan Pekasam (Channa striata) as a Resource of Lactic Acid Bacteria

Abstract

Lactic acid bacteria (LAB) are widely used as probiotics, yet most recognized probiotic sources are derived from dairy and plant-based fermented foods, whereas fermented freshwater fish remains relatively underexplored. This study aimed to isolate and preliminarily screen LAB from Haruan pekasam (Channa striata), a traditional fermented fish product from Kalimantan, to evaluate its potential as a novel local probiotic source. The screening assessed LAB counts, Gram characteristics, lactic acid content, antagonistic activity against Escherichia coli, Salmonella typhi, and Shigella dysenteriae, and cell morphology using scanning electron microscopy (SEM). Fermentation was evaluated on days 8, 10, 12, and 14, with samples analyzed before and after frying. The highest presumptive LAB count occurs on day 14 in the non-fried sample at 2.04 × 10⁶ CFU/mL, while the fried sample reaches 0.75 × 10⁶ CFU/mL. All isolates are Gram-positive and rod-shaped, and SEM reveals cell sizes ranging from 1.462 to 1.682 µm. Lactic acid content ranges from 0.45% to 0.90%. LAB isolates demonstrate in vitro inhibition against all three pathogenic bacteria, with mean inhibition zones of approximately 12.37–13.83 mm. These findings indicate that C. striata is a promising indigenous, non-dairy source of LAB with preliminary probiotic potential and could be developed as a functional fermented food and a local probiotic source from Kalimantan.