|STROMBERG, ZACHARY - University Of Nebraska|
|LEWIS, GENTRY - University Of Nebraska|
|ALY, SHARIF - University Of California|
|LEHENBAUER, TERRY - University Of California|
|Bosilevac, Joseph - Mick|
|CERNICCHIARO, NATALIA - Kansas State University|
|MOXLEY, RODNEY - University Of Nebraska|
Submitted to: International Association for Food Protection Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/20/2015
Publication Date: 7/21/2015
Citation: Stromberg, Z.R., Lewis, G.L., Aly, S.S., Lehenbauer, T.W., Bosilevac, J.M., Cernicchiaro, N., Moxley, R.A. 2015. Prevalence and comparison of detection methods of Enterohemorrhagic Escherichia coli in culled dairy cows. [Abstract] International Association for Food Protection Proceedings. Volume78 (Supplement A): page 294. (P3-219).
Technical Abstract: Introduction: Enterohemorrhagic E. coli (EHEC) serogroups O26, O45, O103, O111, O121, O145 and O157 (EHEC-7) account for the majority of EHEC cases in the U.S. and are adulterants in non-intact, raw beef according to the USDA-FSIS. Purpose: The objectives of this study were to: 1) determine the prevalence of EHEC-7 in fecal, hide, and pre-intervention carcass samples from culled dairy cows at harvest, and 2) evaluate detection methods for EHEC-7 in these matrixes. Methods: One hundred culled dairy cows were sampled at a commercial harvesting facility (June to July 2014). Matched fecal, hide and carcass samples were enriched in E. coli (EC) broth and by immunomagnetic separation (IMS). Enriched samples were directly plated on CHROMagarTM STEC and recovered IMS beads were plated on STEC heart infusion washed blood agar with mitomycin-C, CHROMagarTM O157 and USMARC STEC differential agar. Suspect colonies were screened for Shiga toxin (stx), EHEC-7 O-groups (wzx, wbq, or rfbE), and intimin (eae) by multiplex PCR. Enriched EC broth was tested for EHEC-7 by NeoSEEK™ (Neogen® Corp.), and the Atlas® EG2 Combo assay (Roka® Bioscience). Overall agreement between methods was determined by the Cohen’s ' coefficient and the McNemar’s Chi-square test. Results: EHEC-7 were recovered from 7.0% of fecal samples, 16.0% of hide samples and 1.0% of carcass samples by culture. By NeoSEEKTM, the prevalence of EHEC-7 was 26.0%, 65.0%, and 7.0% for fecal, hide and carcass samples, respectively. By Atlas® EG2, 29.0%, 46.0%, and 28.0% were non-O157 EHEC positive and 29.0%, 51.0% and 3.0% were O157:H7 positive for fecal, hide and carcass samples, respectively. Agreement was observed between culture and NeoSEEKTM for detection of EHEC-O26 (Kappa = .5773, p<0.05) and EHEC-O157 (Kappa = .4012, p<0.05). No agreement was observed between detection methods for other EHEC serogroups. Significance: Detection of EHEC-7 on carcasses suggests that effective interventions are critical to ensure food safety.