New Research on Rapid Identification and Strain Typing of Salmonella in Food

PathoGenetix™ Inc. will present new research this month demonstrating the use of its RESOLUTION™ Microbial Genotyping System to confirm and identify pathogenic Salmonella strains in enriched food samples in less than five hours.

The study findings are detailed in two posters to be presented at the 2013 International Association for Food Protection (IAFP) Annual Meeting in Charlotte, North Carolina, from July 28 - 31, 2013.

The new research demonstrates the ability of the RESOLUTION System’s core Genome Sequence Scanning™ (GSS™) technology to shorten the time for pathogen subtyping and serotype determination from an enriched food sample to five hours, and to quickly derive additional strain and serotype information from a variety of sample types commonly screened for pathogens by the food industry.

Because GSS scans microbial DNA directly from a mixed culture and does not require a pure culture isolate, it greatly reduces the time, complexity, skill and cost required by other molecular and whole genome identification approaches.

The strain type information provided by GSS is comparable to pulsed field gel electrophoresis (PFGE), the current standard for pathogen typing in foodborne outbreak investigation and response. As a result, GSS can enable quicker decisions affecting food safety and public health.

The first study details the use of the RESOLUTION System to reliably differentiate and type Salmonella serovars frequently involved in food safety and public health outbreaks, and to provide identification in less than five hours to aid in epidemiological investigation and source tracking.

This study used a collection of more than 230 Salmonella strains provided by the Food and Drug Administration (FDA), and representing the most frequently encountered Salmonella serovars associated with human illness or isolated from food products.

Strains clustered into serovar-specific branches on the GSS phylogenetic tree, with multi-lineage serovars like Newport and Saintpaul forming more than one distinctly separated branch.

The second poster demonstrates the use of the RESOLUTION System to accurately determine pathogen subtype and serotype information in five hours, and to derive additional strain and serotype information directly from contaminated foods enriched in commercial broths used for pathogen screening in the food industry.

The research spiked ten common Salmonella strains in leafy spinach greens and ground beef, to model "presumptive-positive" enriched samples, including multiple serotypes of Typhimurium and Enteritidis, as well as the Javiana, Newport, Montevideo and Heidelberg serotypes.

Of the 240 samples spiked with Salmonella, GSS positively identified the correct Salmonella serotype in 235 of the samples, and no false positives were recorded from the 24 control samples. (Salmonella was not detected in five samples, due to poor growth of Salmonella in the enrichment of the initial sample, not related to the GSS technology.)

The GSS technology will be commercially available in 2014 in the RESOLUTION™ Microbial Genotyping System.

PathoGenetix will exhibit the RESOLUTION System at IAFP from Sunday evening, July 28, through Tuesday, July 30, and will present its research in two poster sessions on Tuesday, July 30, and Wednesday, July 31.

For more information on the RESOLUTION Microbial Genotyping System or to schedule a demonstration at IAFP, email info@pathogenetix.com.

The IAFP Annual Meeting provides information on current and emerging food safety issues, and is the leading food safety conference worldwide.

The conference addresses the latest science and new and recurring issues in food safety in educational sessions, technical meetings and poster presentations.

For a full schedule of educational sessions and events at the 2013 IAFP Annual Meeting, visit http://www.foodprotection.org/annualmeeting/2013/.