A SALMONELLA MONITORING PROGRAM IN EGG-PRODUCTION FARMS IN GERMANY

A programme monitoring the prevalence of Salmonella infections in egg production farms with different types of flock management was conducte d over a period of 18 months. Three laying hen farms with floor pens a nd five farms with batteries were examined from September 1992 to Marc h 1994. A total of 569 samples (293 feed and 276 faeces) were processe d in parallel by fivefold fractional enrichment in Rappaport/Vasiliadi s medium and in potassium tetrathionate crystal violet broth. By using such elaborate methods, high detection rates of Salmonella were obtai ned. Two thirds of all isolates were found in the third to fifth selec tive enrichment procedure. Salmonella (S.) Tennessee was the most comm on serovar isolated (from 24.5% of the samples) whereas S. Enteritidis was the second most common isolate (23.7%). Salmonella were isolated from 33.1% of the feed samples (97/293), a result which may stimulate further discussion on the prevention of potential contamination of fee d stuff with Salmonella and other pathogens. The number of Salmonella isolations from floor pens was significantly higher than from batterie s. As time progressed an increase in the number of Salmonella isolatio ns occurred in samples taken from the floor pens. The development of a less costly routine monitoring programme to detect Salmonella in samp les taken from barns with layer flocks is recommended.