title: Evaluating the efficacy of beef slaughter line interventions by quantifying the six major non-O157 Shiga toxin producing Escherichia coli serogroups using real-time multiplex PCR.
abstract: Six major Shiga toxin producing Escherichia coli (STEC) serogroups: O26, O103, O145, O111, O121, and O45 have been declared as adulterants in federally inspected raw beef in the USA effective June 4th, 2012 in addition to the routinely tested STEC O157: H7. This study tests a real-time multiplex PCR assay and pooling of the samples to optimize the detection and quantification (prevalence and contamination) of six major non-O157 STEC, regardless of possessing Shiga toxins. To demonstrate the practicality, one large-scale slaughter plant (Plant LS) and one small-scale slaughter plant (Plant SS) located in the Mid-Western USA were sampled, in 2011, before the establishment of 2013 USDA laboratory protocols. Carcasses were sampled at consecutive intervention stations and beef trimmings were collected at the end of the fabrication process. Plant SS had marginally more contaminated samples than Plant LS (p-value 0.08). The post-hide removal wash, steam pasteurization, and lactic acid (≤5%) spray used in Plant LS seemed to reduce the six serogroups effectively, compared to the hot-water wash and 7-day chilling at Plant SS. Compared to the culture isolation methods, quantification of the non-O157 STEC using real-time PCR may be an efficient way to monitor the efficacy of slaughter line interventions.
authors.affiliation: Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA.
authors.forename: Kaushi S T
authors.initials: KST
authors.lastname: Kanankege
authors.affiliation: Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA.
authors.forename: Kelly S
authors.initials: KS
authors.lastname: Anklam
authors.affiliation: Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Fick
authors.affiliation: Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA.
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Kulow
authors.affiliation: Department of Bacteriology, College of Agricultural and Life Sciences, University of Wisconsin, Madison, WI, USA.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Kaspar
authors.affiliation: Department of Food Science, College of Agricultural and Life Sciences, University of Wisconsin, Madison, WI, USA.
authors.forename: Barbara H
authors.initials: BH
authors.lastname: Ingham
authors.affiliation: Department of Animal Sciences, College of Agricultural Life Sciences, University of Wisconsin, Madison, WI, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Milkowski
authors.affiliation: Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA. Electronic address: dopferd@vetmed.wisc.edu.
authors.forename: Dörte
authors.initials: D
authors.lastname: Döpfer
mesh_terms: D000003:Abattoirs; D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D029968:Escherichia coli Proteins / Q000235:genetics*; D005243:Feces / Q000382:microbiology; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods; D000069466:Red Meat / Q000382:microbiology*; D065288:Serogroup; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D014481:United States
chemical_list: D029968:Escherichia coli Proteins
keywords: Beef slaughter plants; Foodborne pathogens; Non-O157 STEC; Pooled samples; Real-time multiplex PCR