Home⇛Scientific Augustinian⇛vol. 15 no. 1 (2025)

Presumptive Identification of Potentially Pathogenic Microorganisms in a Locally Prepared Fermented Rice Food Product Using MALDI-TOF MS

Anna Maria Diana A. Sobrino-salazar | Jose G. Perez

Discipline: environmental sciences

 

Abstract:

Traditional fermented foods are valued for their cultural heritage, sensory appeal, and nutritional benefits. However, spontaneous fermentation practices, which are often conducted in household settings, lack standardized microbial control and may pose food safety risks because of the proliferation of opportunistic or potentially pathogenic microorganisms. This study investigated the microbial composition of a locally prepared rice-based fermented food product using culture-dependent techniques and Matrix-Assisted Laser Desorption/Ionization Time -of-Flight Mass Spectrometry (MALDI-TOF MS). Microbial isolates were cultivated on selective media and characterized through morphological and biochemical analyses, followed by proteomic identification using MALDI-TOF MS. A total of 20 microbial isolates representing nine distinct microbial groups were presumptively identified. Dominant presumptively identified isolates included Candida tropicalis, Enterobacter hormaechei, and Pseudomonas aeruginosa. In addition, microorganisms closely matching E. roggenkampii, Serratia marcescens, and Acinetobacter johnsonii—species commonly associated with opportunistic infections—were also detected. Presumptive non-C. albicans isolates with negative germ tube reactions were likewise observed. MALDI-TOF MS enabled rapid presumptive identification, with most isolates yielding high-confidence spectral matches suggestive of species-level identity. The findings revealed a diverse microbial community influenced by spontaneous fermentation practices and limited hygienic control. While fermentative organisms such as C. tropicalis were prevalent and consistent with expected microbial profiles of rice-based fermentations, the presence of environmental and opportunistic microorganisms highlights the importance of microbiological assessment in traditionally fermented foods. This exploratory descriptive study provides preliminary baseline data on microbial diversity and potential food safety concerns associated with artisanal fermentation, emphasizing the need for improved hygiene practices and increased awareness of food safety in culturally rooted food systems.



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