Development of a LIBS assay for the detection of Salmonella enterica serovar Typhimurium from food

Abstract

Laser-induced breakdown spectroscopy (LIBS) is used for the identification of the presence of hazardous bacteria in food. In this study, our main focus was centered on the identification of S. enterica serovar Typhimurium, a Gram-negative foodborne pathogen, in various liquids such as milk, chicken broth, and brain heart infusion due to the infection being most prevalent in raw meat and dairy products. A Nd:YAG laser of operating wavelength 266 nm was used to obtain the spectra from the artificially inoculated liquid samples. A series of experiments were performed to determine the effectiveness of LIBS to discriminate the bacteria from the background liquids. These results are compared with competing modern molecular methods of detection which include polymerase chain reaction (PCR) and quantitative real-time PCR. In addition to analyzing S. enterica serovar Typhimurium, another common Gram-negative, Escherichia coli, as well as Gram-positive pathogen, Staphlycoccus auerus, were used to determine the specificity of the LIBS technique.

A review of the use of laser-induced breakdown spectroscopy for bacterial classification, quantification, and identification

“…This study showed a saturation or flattening out of the response curve at concentrations above 10 11 CFU/mL. Barnett et al tested concentrations of S. enterica that spanned eight decades (10 1 to 10 8 CFU/mL) as measured by DNA concentrations in the specimens prior to LIBS testing [77]. In blood-heart infusion, chicken broth, and milk, LIBS detection limits were 10 5 CFU/mL.…”

“…Barnett et al studied the very important organisms Salmonella enterica (S. enterica) serovar Typhimurium, which is a Gram-negative foodborne pathogen responsible for salmonella [77]. Because this infection is most commonly caused by ingestion of raw meat or dairy products, the bacteria were inoculated into liquid samples of milk, chicken broth, and brain heart infusion.…”

Silver polyvinyl pyrrolidone nanoparticles exhibit a capsular polysaccharide influenced bactericidal effect against Streptococcus pneumoniae

“…Ag and Au ions released into the media were measured using laser induced breakdown spectroscopy (LIBS). The measurement settings were a modification of Barnett et al (2011) . The excitation wavelength used was 266 nm and the laser energy was adjusted to 20 mJ.…”

Laser-induced breakdown spectroscopy (LIBS): an overview of recent progress and future potential for biomedical applications

“…In the food-preparation industry, the utility of using LIBS to rapidly identify bacteria responsible for foodborne contamination such as Salmonella enterica serovar Typhimurium [64] has been demonstrated. In the mining or environmental remediation industry, it has been shown that femtosecond LIBS can be used to discriminate inter-and intra-site differences in soil bacteria (at both the species and strain level) isolated from mining sites as an indicator of environmental soil quality [65].…”