Dietary Exposure to Microbial Contaminants and Antibiotic Resistance Genes: Metagenomic Insights from Traditional Fermented Pork Fat

Traditional foods can represent important dietary sources of chemical and microbial exposures, yet their composition and potential health implications remain poorly characterized. This study aimed to comprehensively characterize the nutritional composition, lipid profile, and microbial community of a traditional fermented pork fat from Northeast India. Six samples of fermented pork fat were collected from different regions were analyzed using physicochemical methods, electrospray ionization mass spectrometry (ESI+-MS), and 16S rRNA gene amplicon sequencing with PICRUSt-based functional prediction. Physicochemical analysis showed that sa-um consisted predominantly of fat (~91% dry weight), with minor amounts of carbohydrates and proteins. Lipid profiling identified diverse mono-, di-, and triacylglycerides, including myristic acid-containing acylglycerides, sterols, and both saturated and unsaturated lipid species, reflecting a complex dietary lipid composition. Metagenomic analysis identified 72 bacterial genera, dominated by the phyla Firmicutes, Proteobacteria, and Bacteroidetes, with Clostridium representing the most abundant genus. Functional prediction suggested that the microbial community was primarily associated with energy, carbohydrate, amino acid, and lipid metabolism. PICRUSt analysis also predicted genes related to antibiotic resistance and bacterial components such as flagellin and lipid A biosynthesis, mainly associated with members of Bacillaceae, Bacteroidaceae, Clostridiaceae, Corynebacteriaceae, and Enterobacteriaceae. The analysis suggests that this traditional fermented pork may represent a potential source of microbial hazards; however, further in-depth studies are required to confirm the presence of viable pathogenic microorganisms, expressed virulence factors, and associated health risks. By integrating nutritional profiling, and metagenomic characterization, this study provides the first comprehensive assessment a traditional fermented foods. The findings establish a baseline for future quantitative exposure assessment and risk evaluation of culturally important fermented foods.