Purpose: To investigate the occurrence of
Listeria
spp., (particularly
L. monocytogenes
), in different foods and to compare diagnostic tools for their identification at species level.
Methods: Samples of high protein foods such as raw meats and meat products and including beef products, chicken, fish and camel milk were analysed for the presence of
Listeria spp. The isolates were characterised by morphological and cultural analyses, and confirmed isolates were identified by protein profiling and verified using API
Listeria system. Protein profiling by SDS-PAGE was also used to identify
Listeria spp.
Results: Out of 40 meat samples, 14 (35 %) samples were contaminated with
Listeria spp., with the highest incidence (50 %) occurring in raw beef products and raw chicken. Protein profiling by SDSPAGE was used to identify
Listeria spp. The results were verified with API
Listeria system. Approximately 25 % of the identified isolates were
Listeria seeligeri
,
Listeria welshimeri
, and
Listeria grayi
(three positive samples), while 16.66 % of the isolates were
Listeria monocytogenes (two positive samples); 16.6 % of the isolates were
Listeria innocua
(two positive samples), while 8.3 % of the isolates were
Listeria ivanovii
(one positive sample).
Conclusion: High protein foods contain different types of
Listeria species; whole-cell protein profiles and API
Listeria system can help in the identification of
Listeria at the species level.
