title: Meta-analysis on the effect of interventions used in cattle processing plants to reduce Escherichia coli contamination.
abstract: Cattle coming from feedlots to slaughter often harbor pathogenic E. coli that can contaminate final meat products. As a result, reducing pathogenic contamination during processing is a main priority. Unfortunately, food safety specialists face challenges when trying to determine optimal intervention strategies from published literature. Plant intervention literature results and methods vary significantly, making it difficult to implement interventions with any degree of certainty in their effectiveness. To create a more robust understanding of plant intervention effectiveness, a formal systematic literature review and meta-analysis was conducted on popular intervention methods. Effect size or intervention effectiveness was measured as raw log reduction, and modeled using study characteristics, such as intervention type, temperature of application, initial microbial concentration, etc. Least-squares means were calculated for intervention effectiveness separately on hide and on carcass surfaces. Heterogeneity between studies (I2) was assessed and factors influencing intervention effectiveness were identified. Least-squares mean reductions (log CFU/cm2) on carcass surfaces (n=249) were 1.44 [95% CI: 0.73-2.15] for acetic acid, 2.07 [1.48-2.65] for lactic acid, 3.09 [2.46-3.73] for steam vacuum, and 1.90 [1.33-2.47] for water wash. On hide surfaces (n=47), least-squares mean reductions were 2.21 [1.36-3.05] for acetic acid, 3.02 [2.16-3.88] for lactic acid, 3.66 [2.60-4.72] for sodium hydroxide, and 0.08 [-0.94-1.11] for water wash. Meta-regressions showed that initial microbial concentrations and timing of extra water washes were the most important predictors of intervention effectiveness. Unexplained variation remained high in carcass, hide, and lactic acid meta-regressions, suggesting that other significant moderators are yet to be identified. The results will allow plant managers and risk assessors to evaluate plant interventions, variation, and factors more effectively.
authors.affiliation: Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, United States.
authors.forename: Samson
authors.initials: S
authors.lastname: Zhilyaev
authors.affiliation: CIMO Mountain Research Centre, School of Agriculture, Polytechnic Institute of Braganza, Braganza, Portugal.
authors.forename: Vasco
authors.initials: V
authors.lastname: Cadavez
authors.affiliation: CIMO Mountain Research Centre, School of Agriculture, Polytechnic Institute of Braganza, Braganza, Portugal.
authors.forename: Ursula
authors.initials: U
authors.lastname: Gonzales-Barron
authors.affiliation: Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, United States.
authors.forename: Katherine
authors.initials: K
authors.lastname: Phetxumphou
authors.affiliation: Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, United States. Electronic address: dang@vt.edu.
authors.forename: Daniel
authors.initials: D
authors.lastname: Gallagher
mesh_terms: D000003:Abattoirs; D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004203:Disinfection / Q000379:methods; D004926:Escherichia coli / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000517:prevention & control; D019453:Escherichia coli O157 / Q000302:isolation & purification; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology / Q000379:methods*; D059022:Food Safety / Q000379:methods; D005517:Foodborne Diseases / Q000517:prevention & control*; D016018:Least-Squares Analysis; D008460:Meat / Q000382:microbiology*; D008461:Meat Products / Q000382:microbiology; D012499:Sanitation / Q000379:methods
keywords: Beef; Cattle; E. coli; Intervention; Meta-analysis; O157