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Baptista F.M.,Copenhagen University | Baptista F.M.,University of Lisbon | Dahl J.,Danish Agricultural and Food Council | Nielsen L.R.,Copenhagen University
Preventive Veterinary Medicine | Year: 2010

The Danish Salmonella Surveillance-and-Control Programme in finisher pigs includes both herd and carcass surveillance. Herd surveillance consists of serological testing of meat-juice samples and classification of herds into three Salmonella seroprevalence levels. At the abattoirs, carcass swabs from five pigs are collected daily and analysed as a pooled sample to evaluate the Salmonella carcass prevalence.This study aimed to investigate factors associated with Salmonella carcass prevalence in Denmark. A total of 20,196 pooled carcass swabs collected in 23 Danish abattoirs were included in the analysis. A multilevel logistic regression model was used taking into account the two-level data structure (abattoir, carcass pool) and adjusting the parameter estimates to the random variation at the abattoir level. Study results indicated that carcass contamination was mainly influenced by the probability that at least one pig contributing to the pool was seropositive, the log-transformed number of seropositive pigs delivered to the abattoir on the same day and weekday. No other factors were found to be significant (P>0.05). Large reductions in the number of seropositive pigs delivered to slaughter are unlikely to result in large reductions of the Salmonella carcass prevalence, unless the number of seropositive pigs can be kept below approximately 200. On average, individual Salmonella carcass prevalence can be kept below 1% by keeping a Salmonella input to the abattoir below approximately 50 seropositive pigs. Variation between abattoirs suggested that improved hygiene practices in some of the abattoirs would reduce the Salmonella carcass prevalence further. © 2010 Elsevier B.V.


Soumpasis I.,University College Dublin | Alban L.,Danish Agricultural and Food Council | Butler F.,University College Dublin
Food Research International | Year: 2012

Human salmonellosis is an important food-borne disease and S. Typhimurium is the most common serotype attributed to pork products. Under a farm-to-fork strategy, reducing the levels of Salmonella-positive pigs entering the slaughterhouse is an important goal. A framework model was developed, where the effect of dynamic (infection characteristics) and non-dynamic (cleanness and disinfection, biosecurity measures, etc.) factors were considered. Four baseline scenarios were created, corresponding to different levels associated with national Salmonella monitoring programs, and sensitivity analyses were run for the non-dynamic factors. Moreover, the option of vaccination was incorporated into the model, in order to provide with a tool for the formulation of an optimum vaccination strategy depending on the characteristics of the vaccine. © 2010 Elsevier Ltd.


Baptista F.M.,Copenhagen University | Halasa T.,Technical University of Denmark | Alban L.,Danish Agricultural and Food Council | Nielsen L.R.,Copenhagen University
Epidemiology and Infection | Year: 2011

Targets for maximum acceptable levels of Salmonella in pigs and pork are to be decided. A stochastic simulation model accounting for herd and abattoir information was used to evaluate food safety and economic consequences of different surveillance and control strategies, based among others on Danish surveillance data. An epidemiological module simulated the Salmonella carcass prevalence for different scenarios. Cost-effectiveness analysis was used to compare the costs of the different scenarios with their expected effectiveness. Herd interventions were not found sufficient to attain Salmonella carcass prevalence <1%. The cost-effectiveness of abattoir interventions changed with abattoir size. The most cost-effective strategy included the use of steam vacuum and steam ultrasound. Given uncertainty of the effect of steam vacuum and steam ultrasound, model results should be updated as more information becomes available. This framework contributes to informed decision-making for a more cost-effective surveillance and control of Salmonella in pigs and pork. © Copyright Cambridge University Press 2010.


Alban L.,Danish Agricultural and Food Council | Soorensen L.L.,Danish Agricultural and Food Council
Fleischwirtschaft | Year: 2010

In Denmark, pigs from herds with unacceptably high levels of Salmonella spp. (level-3 herds) are obliged to undergo slaughter under special sanitary conditions to ensure safe production. Pilot plant studies had shown that hot-water decontamination (HWD) has a significant reducing effect on E. coli (>2 log units reduction) indicating a similar effect on Salmonella spp. HWD implies that each carcass is showered with hot water (temperature 80 °C/176 °F) for 12 to 15 seconds. HWD equipment was therefore installed in one plant belonging to the largest slaughterhouse company in Denmark. Since 2001, all carcasses from high-risk herds undergo HWD. On each day of HWD, swab samples are taken from the surface of five heat-treated carcasses. These samples are analysed qualitatively as a pooled sample for Salmonella. The HWD system and present surveillance data from mid-February 2004 to December 2008 are described. The total number of pigs dealt with by HWD on a single day varied from 11 to 5,290 (median = 1,936). Salmonella was found in 2.6% of the 341 pooled samples corresponding to an individual carcass prevalence of 0.9%. This prevalence is similar to the surveillance results from pork originating from all other pigs in Denmark. Data show that HWD is an effective risk-reducing way of slaughtering pigs from herds with higher risk of Salmonella not just in a pilot plant but also during normal commercial production.

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