Food Safety
search
cart
facebook twitter linkedin
  • Sign In
  • Create Account
  • Sign Out
  • My Account
Food Safety
  • NEWS
    • Latest News
    • White Papers
  • PRODUCTS
  • TOPICS
    • Contamination Control
    • Food Types
    • Management
    • Process Control
    • Regulatory
    • Sanitation
    • Supply Chain
    • Testing and Analysis
  • PODCAST
  • EXCLUSIVES
    • Food Safety Five Newsreel
    • eBooks
    • FSM Distinguished Service Award
    • Interactive Product Spotlights
    • Videos
  • BUYER'S GUIDE
  • MORE
    • ENEWSLETTER >
      • Archive Issues
      • Subscribe to eNews
    • Store
    • Sponsor Insights
  • WEBINARS
  • FOOD SAFETY SUMMIT
  • EMAG
    • eMagazine
    • Archive Issues
    • Editorial Advisory Board
    • Contact
    • Advertise
  • SIGN UP!
Testing & AnalysisMethodsMicrobiological

Salmonella Rapid Culture Method

August 1, 2009

Salmonella is a Gram-negative, rod-shaped, motile bacterium with a widespread occurrence in animals, especially in poultry and swine. Environmental sources of the organism include raw meat, raw poultry and raw seafood, to name only a few. Detection is critical as is the most frequently reported cause of foodborne illness (40,000–50,000 cases reported annually), and the infectious dose can be as low as 1–10 cells.

Current Methods
Current testing methods (FDA/BAM) involve a pre-enrichment step followed by a second selective enrichment step, followed by plating (which can include secondary plating). This process takes 72–96 hours (3–4 days), depending on the food sample being analyzed, and must be followed by biochemical/serological confirmation of Salmonella contamination, increasing the time to results to up to 5 days.

As indicated above, two enrichment steps are typically needed to recover Salmonella since the bacteria are usually present in very low numbers and may be stressed or damaged from food processing methods. These enrichment steps are general enrichments and are designed to cultivate any microorganisms that may be present in the food sample, potentially masking the presence of very low numbers of true pathogens.

In addition, the secondary enrichment media, modified Rappaport Vassiliadis broth, must be prepared from its individual raw materials to ensure sufficient recovery of any contaminating microorganisms.

Rapid Confirmation
To address the need for a rapid, accurate test for confirmation of Salmonella contamination in food products, a new method, the Salmonella Rapid Culture Method, has been developed. This method involves a single enrichment in ONE Broth-Salmonella, followed by plating on Brilliance™ Salmonella chromogenic medium, taking - less than 2 days to generate an initial result. Thermo Scientific recently received AOAC-RI certification for this method (License no. 120802).

ONE Broth-Salmonella is a highly nutritious enrichment broth containing a specific growth promoter to ensure excellent recovery of stressed and damaged Salmonella cells, while inhibiting the growth of competing microorganisms. This effective medium allows enrichment to be performed in a single 18–24 hour incubation, eliminating the need for a secondary enrichment.

Following enrichment, the sample is plated onto chromogenic culture media. Chromogens within the medium enable differentiation of Salmonella colonies (bright purple) from any remaining organisms that are able to grow, such as Klebsiella (blue colonies) and Enterobacter (clear colonies to no growth), thus reducing the number of false positives that require confirmation.

Testing Results
Fresh Salmonella cultures were prepared from frozen stocks using standard enrichment media [tryptic soy broth (TSB), brain heart infusion (BHI)] or ONE Broth-Salmonella) and incubated for 18–24 hours at the appropriate temperatures, according to manufacturers’ or guideline instructions.

Raw ground beef, ground chicken, lettuce, shrimp and egg shells were obtained from local suppliers. Food samples were inoculated with low [~1 colony forming unit (CFU)/25g] or high (~1.1 CFU/g) microorganism amounts. The final inoculated concentrations were confirmed by MPN (most probable number). Side-by-side samples (both inoculated with micro-organisms and uninoculated negative controls) were compared using the Rapid Salmonella method and by the appropriate USDA/FSIS and FDA-BAM reference methods for each matrix.

A total of 102 Salmonella serovars/ strains were obtained and tested as indicated above. Almost all (98 of 102) of these strains produced a positive purple-colored colony. In addition, a total of 30 species not belonging to the genus Salmonella were analyzed in the same manner. All these strains showed atypical (non-purple colonies) or no growth.

Summary
This study demonstrated that the rapid method described above detected almost all serovars of Salmonella when spiked at levels from low to high in food sources in which Salmonella contamination has been observed. Since 98/102 serovars produced the “typical” purple colonies, it is highly unlikely that a specific serovar would go undetected and lead to an outbreak of salmonellosis (the serovars not detected are not typically found in food). By screening such large numbers of serovars/species, Thermo Scientific is helping food companies to feel secure knowing that food is free from Salmonella contamination when tested using this methodology.

In addition, this study demonstrated that it is possible to discriminate between Salmonella species and other selected non-Salmonella organisms, demonstrating the method’s selectivity. It also ensures that samples contaminated with non-Salmonella organisms do not demonstrate a false-positive color development, allowing the proper identification of food pathogens present in the food being tested. This will ensure a safe food supply free of Salmonella while preventing the waste from discarding any false-positive food lots.

This robust method makes rapid identification of pathogens in food products faster and easier, reducing time to market and eliminating the risk of food recalls.

www.remel.com/salmonella

 


Author(s): Thermo Scientific

Share This Story

Looking for a reprint of this article?
From high-res PDFs to custom plaques, order your copy today!

Recommended Content

JOIN TODAY
to unlock your recommendations.

Already have an account? Sign In

  • people holding baby chicks

    Serovar Differences Matter: Utility of Deep Serotyping in Broiler Production and Processing

    This article discusses the significance of Salmonella in...
    Testing & Analysis
    By: Nikki Shariat Ph.D.
  • woman washing hands

    Building a Culture of Hygiene in the Food Processing Plant

    Everyone entering a food processing facility needs to...
    Facilities
    By: Richard F. Stier, M.S.
  • graphical representation of earth over dirt

    Climate Change and Emerging Risks to Food Safety: Building Climate Resilience

    This article examines the multifaceted threats to food...
    Management
    By: Maria Cristina Tirado Ph.D., D.V.M. and Shamini Albert Raj M.A.
Subscribe For Free!
  • eMagazine Subscription
  • Subscribe to eNewsletter
  • Manage My Preferences
  • Website Registration
  • Subscription Customer Service

More Videos

Sponsored Content

Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the Food Safety Magazine audience. All Sponsored Content is supplied by the advertising company and any opinions expressed in this article are those of the author and not necessarily reflect the views of Food Safety Magazine or its parent company, BNP Media. Interested in participating in our Sponsored Content section? Contact your local rep!

close
  • Deli Salads
    Sponsored byCorbion

    How Food Safety is Becoming the Ultimate Differentiator in Refrigerated and Prepared Foods

Popular Stories

Image of Tyson Foods logo and the logos of Tyson Foods brands

Tyson Foods is Reformulating Food Products to Eliminate Petroleum-Based Synthetic Dyes

USDA building.jpg

More Than 15,000 USDA Employees Take Trump Administration's Resignation Offer

Woman reading the warning label on a bottle of wine

A 40-Year Hangover: Efforts to Revive 1980s Advocacy About the Potential Negative Effects of Alcohol Consumption

Events

May 12, 2025

The Food Safety Summit

Stay informed on the latest food safety trends, innovations, emerging challenges, and expert analysis. Leave the Summit with actionable insights ready to drive measurable improvements in your organization. Do not miss this opportunity to learn from experts about contamination control, food safety culture, regulations, sanitation, supply chain traceability, and so much more.

May 14, 2025

Proven Practices for Allergen Management

Live Streaming from the Food Safety Summit: This session tackles the importance and impact of allergen management in product development, production, and labeling. 

May 15, 2025

Alarm Fatigue: How to Ensure Out-of-Compliance Alarms Serve Their Purpose and Ensure Food Safety

Live Streaming from the Food Safety Summit: This session will explore the challenges of setting effective alarms for out-of-compliance hot and cold holding temperatures in food safety management. 

View All

Products

Global Food Safety Microbial Interventions and Molecular Advancements

Global Food Safety Microbial Interventions and Molecular Advancements

See More Products
Environmental Monitoring Excellence eBook

Related Articles

  • Helping You Release Product Sooner: Salmonella Rapid Culture Method

    See More
  • Whole-Genome Sequencing May Be Hot, But Which Rapid Micro Method Won’t Leave You Burned?

    See More
  • Development of a Rapid Method for Enumerating Specific Types of Bacteria

    See More

Related Products

See More Products
  • Food-Forensics-3D.jpg

    Food Forensics Handbook Practice, Instrumentation, Case Studies

  • 1118396308.jpg

    High Throughput Analysis for Food Safety

  • 1444333348.jpg

    Handbook of Food Safety Engineering

See More Products

Related Directories

  • Salus Scientific Inc.

    Providing innovative bacteria enrichment and culture mediums to detect pathogenic, spoilage, or other contaminating bacteria. The Actero™ Enrichment Media benefits are one step enrichment, faster “time-to-results”, and targeted accuracy. Actero™ EZ-Media Bag provides pre-measured and pre-sterilized enrichment media that can be prepared in under 30-minutes. The newest innovation is a true Multiplex enrichment media that simultaneously enriches 2 to 3 pathogenic bacteria in one step. “Always Easy. Always Right.”
  • Bio-Rad Laboratories

    Bio-Rad produces tests for food, water and cannabis safety, including real-time PCR test kits for detection of key pathogens, culture media for nutritive enrichment and RAPID chromogenic media with easy colony identification for detection of pathogens and enumeration of quality indicators
  • QualiTru Sampling Systems

    Since 1983, QualiTru Sampling Systems® (formerly QMI) has been the leader in the science of aseptic liquid sampling with innovative, easy-to-use, versatile and cost‑effective sampling systems that help the dairy, beverage and liquid food industries produce safe, quality products across the U.S. and in over 30 countries worldwide.
×

Never miss the latest news and trends driving the food safety industry

eNewsletter | Website | eMagazine

JOIN TODAY!
  • RESOURCES
    • Advertise
    • Contact Us
    • Directories
    • Store
    • Want More
  • SIGN UP TODAY
    • Create Account
    • eMagazine
    • eNewsletter
    • Customer Service
    • Manage Preferences
  • SERVICES
    • Marketing Services
    • Reprints
    • Market Research
    • List Rental
    • Survey/Respondent Access
  • STAY CONNECTED
    • LinkedIn
    • Facebook
    • Instagram
    • X (Twitter)
  • PRIVACY
    • PRIVACY POLICY
    • TERMS & CONDITIONS
    • DO NOT SELL MY PERSONAL INFORMATION
    • PRIVACY REQUEST
    • ACCESSIBILITY

Copyright ©2025. All Rights Reserved BNP Media.

Design, CMS, Hosting & Web Development :: ePublishing