A new Salmonella surveillance and control programme in Danish pig herds and slaughterhouses

The Danish Salmonella Surveillance and Control Programme for pigs operates at all stages of the production chain and has been applied nationally since 1995. Due to the program the level of Salmonella in Danish pork has declined from 3.5 % in 1993 to 0.7 % in the year 2000. Simultaneously, the number of human cases with salmonellosis due to pork has declined from approximately 1,144 in 1993 to 166 in 2000.

In year 2001, the programme has been improved at a number of stages. A new classification scheme for the serological surveillance of finisher herds has been developed. The individual test cut-off in the mix-ELISA has been reduced to 20 OD %. Only herds producing more than 200 finishers/year are sampled.

Based on the serological result from the last 3 months a new weighted salmonella index is calculated. The Danish Bacon and Meat Council has agreed on a new stricter penalty system. Level 2 and 3 herds get a penalty of 2 % and 4 % of the value per slaughter carcass, respectively. A new method of Salmonella testing on carcasses has been introduced; 5 carcasses per slaughter day are swabbed at 3 defined areas at 100 cm(2) for each sample.

This method is more sensitive than the one used previously, Herds infected with multiresistant Salmonella Typhimurium DT104 have to follow special restrictions. These include a requirement for a herd intervention plan, restriction on livestock trade, and a requirement for special slurry handling. Carcasses from DT 104 herds must be heat-treated or decontaminated with hot water.