Item V. Raw Dataset

Lactic acid bacteria (LAB) are generally mesophilic microorganisms widely recognized for their roles in food fermentation and preservation, but information on their presence in heat-treated, non-fermented foods remains limited. This study aimed to isolate, identify, and characterize thermotolerant LAB from sarsa na uyáng, a cooked traditional Filipino dish. Isolates were evaluated for typical LAB traits, thermotolerance at 50, 75, and 100°C, molecular identity, and phylogenetic relationships using 16S rRNA sequencing. Four LAB isolates that survived exposure to 100°C were classified as thermotolerant. Among these, isolate L16 exhibited the highest heat resistance and the greatest post-heat recovery, whereas the remaining isolates displayed varying degrees of thermal resilience. This apparent thermotolerance may have occurred due to factors such as cell aggregation or biofilm-like clustering, sublethal injury during heat exposure, exopolysaccharide production, and the presence of heat-resistant subpopulations within otherwise heat-sensitive cultures. Moreover, all four thermotolerant isolates were identified as Weissella confusa and clustered together in phylogenetic analysis. These findings demonstrate that sarsa na uyáng may harbor thermotolerant LAB capable of surviving extreme heat stress, highlighting their potential applications in probiotic development, heat-processed food production, and industrial biotechnology.