The Styrian Salmonella surveillance programme in pork

The implementation of Directive 92/117/EEC ("Zoonoses Directive"), which re quires measures to be taken for the control of "food-borne diseases", resul ted in the setting up of a Salmonella surveillance programme for pork produ ction in Styria. To analyse the status quo, the prevalence of Salmonella in pig farms was assessed. On the basis of a representative random sample a t otal of 833 slaughter pigs from 510 herds was examined for Salmonella. The examination was focused on the mesenteric and liver lymph nodes and intesti nal contents of the animals and was performed in four consecutive series (w inter 1997 - summer 1998). Twenty-four animals (2.9 %) from twenty-two diff erent farms (4.3 %) were identified as latent carriers of Salmonella. By ex trapolation from the sample to the population of Styrian slaughter pigs the estimated percentage (p) over cap of Salmonella-positive pigs was also cal culated at 2.9 % [S = 95 %; Cl (1.9 % less than or equal to p less than or equal to 4.2 %)]. Salmonella was most frequently isolated from mesenteric a nd liver lymph nodes (twenty isolates; 2.4 %). Only in seven cases (0.8 %) Salmonella was found in the intestinal contents. The total of twenty-seven Salmonella isolates comprised six different serovars, with S. enteritidis, S. typhimurium and S. hadar being the most frequent ones. Four serovars of S. typhimurium DT 104 and five serovars of S. hadar were identified as mult i-resistent. The examination of the cut surfaces of 1,040 split carcasses o n the basis of a wipe sample yielded a Salmonella detection rate of 0.4 %. In the serological examination of 2,310 blood samples of slaughter pigs fro m 330 pig farms using the SALMOTYPE(R) Meat Juice ELISA fourteen animals (0 .6 %) from ten farms (3 %) were found to be positive, and fourty-one animal s (1.8 %) from twenty-seven farms (8.2 %) were suspected to be positive. Po sitive or doubtful results lead to epidemiological investigations in the re spective herds. The Styrian Salmonella surveillance programme for pork prod uction has been in operation since may 1999.