Rapid viable-cell detection of foodborne pathogenic bacteria using membrane-assisted concentration and phage amplification

초록

Rapid and accurate detection of viable foodborne pathogens is essential for food safety monitoring. Conventional nucleic acid-based methods cannot differentiate between live and dead cells, while culture-based assays are time-consuming. Therefore, a rapid and quantitative platform for viable-cell detection is needed. We developed an integrated membrane-assisted concentration-phage amplification assay-quantitative real-time PCR (MC-PAA-qPCR) for rapid and selective quantification of viable Bacillus cereus and Salmonella Enteritidis in fresh produce. Bacterial cells were concentrated using optimized polyvinylidene difluoride membrane filtration, and host-specific lytic bacteriophages selectively infected viable target cells, enabling phage amplification. Progeny phages were quantified by real-time qPCR to estimate initial bacterial concentrations. The system was evaluated in buffer and artificially contaminated kimchi cabbage samples. The MC step improved concentration efficiency for both strains. The PAA-qPCR assay achieved rapid quantification within 2-2.5 h, demonstrating strong linearity (R2 >= 0.95) across a dynamic range of 101-107 CFU/mL. The platform effectively discriminated viable from non-viable cells and maintained high precision in mixed microbial populations. In contaminated kimchi cabbage, quantification accuracy reached 98.8 +/- 3.0% compared with culture-based enumeration, with significantly reduced assay time. These results demonstrate that the MC-PAA-qPCR workflow enables rapid, viability-linked detection of target bacteria, supporting its potential application in the food industry.

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