Cost-effectiveness of Escherichia coli O157:H7 control in the beef chain

Beef is considered to be an important source of food-borne disorders caused by the bacteria Escherichia coli O157:H7 (VTEC O157). Through the beef-supply chain, this bacterium can pose a risk to public health. The objective of this research is toprovide quantitative insight in the cost-effectiveness of interventions to control VTEC O157 at two levels of the Dutch beef-supply chain: dairy farms and industrial beef slaughterhouses.At the slaughterhouse level, seven decontamination measures were evaluated, namely hot-water wash, lactic-acid rinse, trimming, steam-vacuum, steam-pasteurization, hide-wash with ethanol and gamma irradiation. The effectiveness of the decontamination measures was estimated based on a stochastic epidemiological simulation model. The net costs of the decontamination measures were calculated with a deterministic economic model. To assess the effectiveness of on-farm interventions, a transmission model that mimics the dynamics of VTECO157 bacteria in a typical Dutch dairy herd, was used. The evaluated on-farm interventions were vaccination, diet modification, probiotics (colicin) and additional hygiene. The net costs of the on-farm interventions were based on a deterministic economic model. The effectiveness of the on-farm interventions and slaughterhouse decontamination measures was expressed as the prevalence of contaminated carcass quarters. The baseline prevalence (i.e., without intervention) was estimated to be 4.3%. The net costs of implementing single decontamination methods at the slaughterhouse were calculated to be 0.22 to 0.65 per carcass quarter which is 16% to 40% of the net profit per carcass. The costs of combining decontamination methods at the slaughterhouse vary from 0.44 to 1.88 per carcass quarter and the costs of irradiation were estimated at 4.65 per carcass quarter. The annual costs of implementing on-farm interventions for the supplying dairy farms were calculated to be 1.75, 2.25, 18 and 40 per carcass quarter for probiotics, vaccination, additional hygiene and diet modification respectively. It is concluded that: i) applying decontamination measures at the slaughterhouse level is more cost-effective than applying interventions at the farm level or at the chain level (i.e., both slaughterhouse and farm levels), ii) carcass trim and steam-pasteurization are the most cost-effective slaughterhouse interventions, and iii) vaccination and colicin supplementation have the best cost-effectiveness ratios of the on-farm interventions.