Isolation of listeria species from sheep and goat milk in Elazığ vicinity

53 7. SUMMARY In this study, raw milk samples were collected from healthy and aborted individuals on 14 sheep and 12 goat flocks in Elazığ province and its central villages between April and September 1995, to investigate the presence of Listeria species. The total number of samples collected was 300. Of these, 100 were collected from healthy sheep and 50 from aborted sheep. The remaining 150 samples were from healthy goats. The method described by International Dairy Federation (IDF) was used for the isolation of Listeria spp. According to this procedure, milk samples in modified Listeria selective enrichment broths were incubated at 30 °C for 24 and 48 h and streaked on LSA at 24 and 48 h. The overall proportion of Listeria spp. isolated from raw milk samples was 1.66% (5/300). Four of these (4%) were obtained from healthy sheep and only one (0.66%) was from a healthy goat. Three of the sheep isolates were identified as L. welshimeri and one was L. dentrificans. The Listeria spp. isolated from the goat was determined to be L. welshimeri. No isolation was made from the milk samples of aborted sheep. All isolates were obtained from enriched 48 h samples. No isolation was made at 24 h. No pathogen Listeria spp. were isolated from raw milk samples in this study. In conclusion, the absence of L. monocytogenes in raw milk samples suggests that the isolation of this species in milk products (e.g. cheese) in other studies might have been a consequence of environmental contamination rather than infected milk. The findings of this study also suggest that listeric abortion is not a serious problem in animal population of this region.