# An Overview of the Public Health Challenges in Diagnosing and Controlling Human Foodborne Pathogens
## 4 Diagnostic Approaches of Foodborne Pathogens
### Methods Based on Nucleic Acids
#### 4.2.1 Polymerase Chain Reaction (PCR)
[134] used the quantitative PCR method for analyzing samples collected from 239 poultry operations as part of their study to identify Salmonella in the samples. A quadruple probe quantitative PCR method has been developed by [PERSON] et al. [135] in order to determine whether there were different servours of _Listeria monocytogenes_ present in packaged and processed meats. There is a high level of precision, speed and sensitivity associated with the probes. Their study findings were crucial for identifying if there was a risk of _Listeria monocytogenes_ contamination in meat products as well as how to establish routine monitoring of the presence of persistent strains of this organism in ready-to-eat meat products as a precaution. According to [PERSON] et al. [124], a nationwide standard procedure in combination with quantitative PCR techniques was used to systematically identify 60 animals, marine and dairy products in order to determine their susceptibility to foodborne illness. Quantitative PCR technology actually showed a higher rate of pathogen detection than the national standard approach, even though _Staphylococcus aureus_, an essential pathogen, was missed. The presence of _Salmonella_ in grilled ham was reported by [PERSON] et al. [136]. According to the authors, it appears that the limit of detection was set at \(10^{3}\) CFU/g for this organism. There were three organisms identified in the analysis of fresh pork by [PERSON] et al. [137]: _Staphylococcus aureus_, _Salmonella_ and _Shigella_. Their detection time was less than 8 h, which is significantly shorter than that of standard PCR detection times. According to the study's findings, _Shigella_ had a detection limit of 6.8 CFU/g, _Salmonella_ 2.0 CFU/g, and _Staphylococcus aureus_ 9.6 CFU/g. An increase in the detection efficiency of _Escherichia coli_ O157:H7 was observed by [PERSON] et al. [138], and the species of this organism is now known to be easy to detect. In some cases, the detection might only take a couple of minutes to complete. According to the findings of the study, the detection limit for this strain was 78 pg/tube. Standard culture techniques, along with quantitative PCR, yielded reliable results, but by using quantitative PCR, the results were obtained more quickly. Because the quantitative PCR technology uses a closed system for preparing the product, false positives from contaminants at the moment of analysis can be avoided. Quantitative PCRs are extremely quick since they are performed on a standalone instrument without any need for electrophoresis, resulting in a significant reduction in the total time of the process compared to conventional PCR, which require electrophoresis after the amplification is complete. The real challenge with multiple probe Quantitative PCR is that it is challenging to perform as the operator needs a high level of technical skill, the equipment is expensive and the technology itself is expensive [139,140].