Selective PCR Detection of Salmonella Typhimurium in Low-Level Samples

The patent replaces conventional mechanical microbiological culturing methods with a molecular biology-based PCR detection system. Specifically, it uses nucleic acid amplification technology to detect Salmonella DNA directly from samples, eliminating the need for lengthy bacterial cultivation processes while maintaining high detection accuracy. The method employs specific primers and probes to amplify and detect Salmonella genetic material, reducing detection time from days to hours.

The patent implements preliminary enrichment steps before PCR detection to enhance the sensitivity of the method. By performing selective enrichment cultivation under controlled conditions prior to DNA extraction and amplification, the method ensures that even low levels of Salmonella in the original sample are sufficiently amplified for detection, thereby maintaining high detection accuracy while still significantly reducing overall detection time compared to traditional methods.

The patent employs selective enrichment cultivation as a preliminary step before PCR detection. This enrichment process selectively amplifies Salmonella bacteria from the sample under controlled conditions, ensuring that even trace amounts of the pathogen are increased to detectable levels. This preliminary action maintains high detection reliability by ensuring sufficient target material is present for accurate PCR amplification and detection.

The patent replaces direct cultural detection methods with molecular amplification technology. Instead of relying on visible bacterial growth which requires sufficient initial bacterial concentrations, the method uses PCR to amplify Salmonella-specific DNA sequences. This substitution allows detection of extremely low bacterial concentrations that would be undetectable by conventional culturing, thereby improving the relationship between detection reliability and bacterial concentration.

The patent combines multiple detection capabilities into a single integrated PCR-based system. By merging DNA extraction, amplification, and detection steps into one standardized protocol with specific primers and probes for Salmonella, the method maintains procedural simplicity while dramatically increasing testing throughput. The standardized nature of PCR allows for automation and parallel processing, enabling rapid testing of multiple samples simultaneously to meet regulatory requirements.

The patent changes the fundamental detection parameter from observing bacterial growth (time-consuming) to detecting genetic material (rapid). By shifting from measuring bacterial colony formation over days to detecting amplified DNA sequences in hours, the method transforms the detection parameter while maintaining procedural accessibility. This parameter change enables rapid results that meet food safety regulatory requirements without significantly complicating the overall testing process.