title: Comparison of sampling methods for microbiological testing of beef animal rectal/colonal feces, hides, and carcasses.
abstract: This study compared sampling methods for detecting Escherichia coli O157:H7 and Salmonella in beef cattle feces and on hides and carcasses and for enumerating E. coli biotype I counts (ECC) on carcasses. Fecal samples were collected by rectal/colonal palpation and colonal sponge swabbing. Hides were sampled by sponge swabbing three sites, hair clipping, excision, rinsing, and gauze swabbing, whereas carcasses were sampled by three-site thoracic and pattern-mark sponge swabbing and tissue excision. Overall, irrespective of sampling method, 36.7, 13.3, and 0.0% of lots contained at least one E. coli O157:H7-positive hide, fecal, and carcass sample, respectively, while the corresponding prevalence of Salmonella was 70.0, 16.7, and 6.7%, respectively. For hide sampling, excision and gauze swabbing yielded the fewest (13.3%) E. coli O157:H7-positive samples, while hair clipping and sponge swabbing yielded the most (23.3%). None of the carcass-sampling methods detected E. coli O157:H7 or differed (P > 0.05) in their ability to enumerate ECC. Colonal swabbing was the most effective (10.0%) method for detecting E. coli O157:H7 in feces. No differences (P > 0.05) in Salmonella prevalence were observed between carcass-sampling methods, although three-site sponge swabbing and tissue excision detected the most (3.3%). Hide rinsing was the most effective (P < 0.05) Salmonella detection method (63.3%), but dangers associated with its application may preclude its use by industry; there were no differences (P > 0.05) among other hide-sampling methods. No differences (P > 0.05) in Salmonella detection were observed between fecal-sampling methods. Overall, three-site sponge swabbing was the most feasible and effective sampling method for the detection of E. coli O157:H7 and Salmonella on hides and carcasses.
authors.affiliation: Center for Red Meat Safety, Department of Animal Sciences, Colorado State University, Fort Collins 80523-1171, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Ransom
authors.forename: K E
authors.initials: KE
authors.lastname: Belk
authors.forename: R T
authors.initials: RT
authors.lastname: Bacon
authors.forename: J N
authors.initials: JN
authors.lastname: Sofos
authors.forename: J A
authors.initials: JA
authors.lastname: Scanga
authors.forename: G C
authors.initials: GC
authors.lastname: Smith
mesh_terms: D000818:Animals; D002417:Cattle / Q000382:microbiology*; D003106:Colon / Q000382:microbiology; D015169:Colony Count, Microbial; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology*; D005516:Food Microbiology; D010173:Palpation / Q000662:veterinary; D012007:Rectum / Q000382:microbiology; D012475:Salmonella / Q000302:isolation & purification*; D012867:Skin / Q000382:microbiology