Malaysian fermented shrimp paste (belacan): A source of potential probiotic lactic acid bacteria

Abstract

In the present work, lactic acid bacteria (LAB) isolated from Malaysian fermented shrimp paste, locally known as belacan, were screened for their probiotic potential. Seventeen isolates were characterised after a preliminary subtractive screening based on morphology (catalase-negative and Gram-positive cocci/bacilli). The isolates were evaluated based on their tolerance towards the gastrointestinal environment, haemolytic properties, antagonism effect against selected pathogens, and antibiotic resistance patterns. The isolates were also molecularly identified via 16S rRNA sequencing. Out of 17, three isolates (BE3, BE7, and BE16) demonstrated tolerance to pH 2.5 (survival rates above 90%) and 0.3% bile salts (survival rates above 50%). Further screening performed on the three isolates indicated that all strains did not show undesirable haemolytic activities, and could inhibit the growth of Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Salmonella Typhimurium to varying degrees. Additionally, the isolates were susceptible to ampicillin and chloramphenicol antibiotics, and resistant to nalidixic acid, streptomycin, and vancomycin antibiotics. The 16S rRNA gene sequence analysis identified the isolates as Lactobacillus plantarum with 98, 100, and 99% similarity for BE3, BE7, and BE16, respectively. Therefore, these findings suggested that LAB isolated from Malaysian fermented shrimp paste exhibited promising probiotic properties.