For the selective enrichment of Listeria spp. 1 ml of cell suspension was added to 9 ml Buffered-Listeria-Enrichment-Broth (BLEB) (Merck KGaA, Darmstadt, Germany). After 2 h of preincubation at 30°C Listeria-Selective-Enrichment supplement (Merck KGaA, Darmstadt, Germany) was added and the culture was further incubated at 30°C. After 24 h, 48 h, and 7 days 0.1 ml of the enrichment culture were transferred to 10 ml Half-Fraser-Bouillon (Merck KGaA, Darmstadt, Germany) and incubated aerobically at 37°C. Enrichment culture dependent detection of Listeria spp. was conducted after 24 and 48 h using Oxford-Agarplates (Merck KGaA, Darmstadt, Germany) and Palcam-Agarplates (Merck KGaA, Darmstadt, Germany) inoculated with the second enrichment culture. In case of a detection of Listeria spp. Rapid‘L.mono medium (Bio-Rad Laboratories GmbH, Munich, Germany) plates were used to identify L. monocytogenes. After inoculation, the identification plates were incubated at 37°C for 48 h.
In order to enrich S. enterica cells, 1 ml of cell suspension was added to 9 ml of BPW and incubated aerobically 37°C for 24 h. Afterwards cultures were streaked out on Xylose-Lysine-Deoxycholat (XLD) agar plates (Fluka, Buchs, Switzerland) and incubated at 37°C for 24 h in order to identify Salmonella spp.
In order to enrich S. enterica cells, 1 ml of cell suspension was added to 9 ml of BPW and incubated aerobically 37°C for 24 h. Afterwards cultures were streaked out on Xylose-Lysine-Deoxycholat (XLD) agar plates (Fluka, Buchs, Switzerland) and incubated at 37°C for 24 h in order to identify Salmonella spp.