P2-53 Comparative Evaluation of the 3M™ Molecular Detection Assay Escherichia coli O157 (including H7) for the Detection of Escherichia coli O157 in Raw Ground Beef

Tuesday, July 30, 2013
Exhibit Hall (Charlotte Convention Center)
Gabriela Stancanelli, 3M Food Safety, Buenos Aires, Argentina
Julián De la Torre, Universidad Nacional de La Plata, Buenos Aires, Argentina
Luciano Linares, Universidad Nacional de La Plata, Buenos Aires, Argentina
Emanuel Ortega, Universidad Nacional de La Plata, Buenos Aires, Argentina
Virginia Aliverti, Universidad Nacional de La Plata, Buenos Aires, Argentina
Victoria Brusa, Universidad Nacional de La Plata, Buenos Aires, Argentina
Lucia Galli, Universidad Nacional de La Plata, Buenos Aires, Argentina
Pilar Peral Garcia, Universidad Nacional de La Plata, Buenos Aires, Argentina
Julio Copes, Universidad Nacional de La Plata, Buenos Aires, Argentina
Gerado Leotta, Universidad Nacional de La Plata, Buenos Aires, Argentina
John David, 3M Food Safety, St. Paul, MN
Introduction:  Escherichia coli O157:H7 is a pathogen associated with foodborne diseases. The infection by E. coli O157:H7 can cause sporadic cases or outbreaks of diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS). The Argentine Food Code (CAA), Article 255 establishes the absence of this pathogen in five 65 g samples of ground beef.

Purpose: The purpose of this evaluation was to compare the 3M™ Molecular Detection Assay E. coli O157 (including H7) protocol to the USDA/FSIS-MLG method for raw ground beef.

Methods: A total of 77 samples were artificially inoculated at a level of 10 CFU/65 g with five strains of E. coli O157:H7 and one strain of E. coli O157: non-toxigenic HNT, isolated in Argentina from foods.  Sixteen strains of non-E. coli were analyzed to determine the specificity of the method in levels of 10 CFU/65 g.

Results: All contaminated samples with E. coli O157 were detected by the MDS as positive in real time after 15 minutes. All contaminated samples with non-E. coli were detected as negative with the system in 75 minutes.

The results also indicate 100% inclusivity and 100% exclusivity with no false positives or false negatives. Additionally, this study demonstrated the usefulness of this molecular assay owing to its rapidity, sensitivity and specificity, and how these features can be applied directly in the field of the food industry for detecting prevalent pathogens in Argentina.

Significance: Statistically, there was no significant difference between the MDS E. coli O157 (including H7) when compared to the USDA/FSIS-MLG reference methods as indicated by McNemar’s X2 value of 0.0. The MDS E. coli O157 provides a rapid and accurate solution for the detection of E. coli O157 in raw ground beef.