Estimation of limit of detection of Salmonella typhimurium in artificially contaminated chicken meat by cultured-based and polymerase chain reaction techniques

Yousif M Sharif,Bizhar A Tayeb

doi:10.33899/ijvs.2020.127328.1496

Abstract

The objective of this study was to develop Polymerase Chain Reaction (PCR) procedure for detection of Salmonella Typhimurium in artificially contaminated chicken meat. The experiments were conducted with various dilutions of Salmonella Typhimurium reference the American Type Culture Collection ATCC (ATCC13311TM 4.4*107) High concentration 4.4*103 Colony Forming Units (CFU)/ml, low concentration 4.4*102 CFU/ml, very low concentration 4.4*101 CFU/ml inoculated in chicken meat, in order to determine limits of detection (LOD), optimum incubation times 18 to 20 hours of pre-enrichment in Buffered Peptone Water (BPW 1%). Hence, cultural methods and DNA extraction were performed according to kits instruction. The microbiological cultural test was capable to detect 1.76 CFU/mL, whereas PCR examination was able to detect 0.18 CFU/ml of initial dilution of Salmonella Typhimurium inoculated in chicken meat. Interestingly, the results were achieved in a less time period than that of classical culture. The PCR technique is beneficial in the methodology for detection of Salmonella in chicken meat.

Highlights

Salmonella is one of the most important pathogen that can infect human through ingestion of contaminated food with a sub-classification of more than 2500 serovars including Typhimurium related to foodborne salmonellosis in human [1,2]
The experiments were conducted with various dilutions of Salmonella Typhimurium reference the American Type Culture Collection ATCC (ATCC13311TM 4.4*107) High concentration 4.4*103 Colony Forming Units (CFU)/ml, low concentration 4.4*102 CFU/ml, very low concentration 4.4*101 CFU/ml inoculated in chicken meat, in order to determine limits of detection (LOD), optimum incubation times 18 to 20 hours of preenrichment in Buffered Peptone Water (BPW 1%)
The specificity of primer pairs used in the current study showed through the results of the Polymerase Chain Reaction (PCR) technique in detection of particular organisms in chicken

Summary

Introduction

Salmonella is one of the most important pathogen that can infect human through ingestion of contaminated food with a sub-classification of more than 2500 serovars including Typhimurium related to foodborne salmonellosis in human [1,2]. Salmonella should not be detected in 25g of food samples according to a number of governmental standard regulations and recommendations [7] This kind of techniques could be time consuming and not sensitive enough to detect low-abundance of the level of contamination [8]. PCR is a major molecular biology assay and considered as a novel and sensitive technique in the field of laboratory diagnostics [9] This new technology allows detecting of various foodborne pathogens including salmonella in very low bountiful [10,11]. A pair of primers was used in the current study that specific for detection of the gene InvA

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Conclusion