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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Meat Safety and Quality » Research » Publications at this Location » Publication #416015
Research Project: Holistic Tactics to Advance the Microbiological Safety and Quality of the Red Meat Continuum

Location: Meat Safety and Quality

Title: Development of hydrolysis probe assays for the specific detection of pathogenic Escherichia coli O26, O111, O103, and O121 strains: Multi-country validation study

Author
item VALEZ, FRANK - Florida State University
item Bosilevac, Joseph - Mick
item SALAZAR, GLORIA - Florida State University
item KAPOOR, HARSIMRAN KAUR - University Of Georgia
item MISHRA, ABHINAV - University Of Georgia
item MADOROBA, EVELYM - Department Of Biochemistry And Microbiology, University Of Zululand
item STANFORD, KIM - University Of Lethbridge
item FACH, PATRICK - French Agency For Food, Environmental And Occupational Health & Safety (ANSES)
item DELANNOY, SABINE - French Agency For Food, Environmental And Occupational Health & Safety (ANSES)
item STEPHAN, ROGER - University Of Zurich
item SINGH, PRASHANT - Florida State University

Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: E. coli can belong to many serogroups like O26, O103, O111, and O121. Most are harmless but some produce Shiga toxin, and Shiga toxin producing E. coli (STEC) cause disease outbreaks around the world. Many countries test foods for STEC using tests that cannot tell the difference between dangerous STEC and harmless E. coli of these serogroups and must destroy any positive testing foods. This study reports a new test that more accurately detected disease causing STEC-O26, O103, O111, and O121 in beef and spinach, using strains from Canada, France, South Africa, Switzerland and the United States. The new test identified all contaminated samples and accurately determined 95% of the time if they were STEC. Food testing laboratories worldwide can use this test to detect disease causing STEC which will reduce product and financial losses from misleading positive results caused by harmless E. coli.

Technical Abstract: Enterohemorrhagic Escherichia coli strains are major foodborne pathogens frequently implicated with red meat outbreaks and are a cause of global food safety concerns. Several commercial assays are available for detecting virulent E. coli belonging to serogroups O26, O103, O111, and O121. However, none of these assays can differentiate disease-causing strains carrying crucial virulence genes from non-pathogenic strains belonging to the same serogroup. This study aimed to standardize and validate four hydrolysis probe assays for the specific detection of pathogenic strains of E. coli O26, O103, O111, and O121. Primers and probes were designed to target previously identified single nucleotide polymorphisms conserved among pathogenic strains of each target serogroup. The standardized assays were validated using a large number of pure cultures (n = 248) from Canada, France, Switzerland, and the United States; laboratory-inoculated beef and spinach samples (n = 132), fractionally inoculated ground beef samples (n = 390), and DNA samples from the federal red meat surveillance program (n = 166). Overall, data from the study demonstrated the assay's ability to predict strains' virulence profile with an accuracy of 94.8%. Food testing laboratories worldwide can use these assays as a molecular confirmation tool to reduce product and financial losses from misleading positive results caused by non-pathogenic strains.