For isolation of Salmonella spp., 25 g of each sample was
homogenized in 225 ml of lactose broth and incubated at
37 C overnight. One milliliter of this pre-enrichment culture
was inoculated into tubes containing 10 ml tetrathionate
(TT) broth (Oxoid, CM0029) for enrichment, and
incubated 24 h at 37 C. Bacteria growing in TT broth were
streaked on xylose lysine desoxycholate (XLD) agar
(Oxoid, CM0469) and MacConkey agar (Oxoid, CM0007)
and incubated at 37 C overnight. The plates were examined
for the presence of typical colonies of Salmonella, i.e. pink
colonies with or without black centres on XLD agar and
colourless colonies on MacConkey agar. Presumptive Salmonella
colonies were then subjected to initial screening
tests using triple sugar iron agar, lysine iron agar , urea broth and lysine
decarboxylase broth . All biochemical tests
were performed at 37 C for 18–24 h . Presumptive positive colonies were subjected
to Poly O and Poly H (Denka
Seiken) slide agglutination tests. Salmonella serotyping
was performed according to the Kauffmann–White scheme at Enteric Pathogens Reference Laboratory
of Refik Saydam National Hygiene Center, Ankara,
Turkey.