Listeria monocytogenes and other Listeria species in retail meat and milk products in Addis Ababa, Ethiopia

Abstract

Abstract
Background: Listeriosis is one of the important emerging bacterial zoonotic infections worldwide. Among the
different species of the genus Listeria, Listeria monocytogens is known to cause listeriosis in humans and animals.
Information on the occurrence and distribution of Listeria monocytogenes and other Listeria species is very limited
both in the veterinary and public health sectors in Ethiopia.
Objectives: The present study was undertaken to determine the occurrence and distribution of Listeria monocytogenes
and other Listeria species in retail meat and milk products in Addis Ababa, Ethiopia.
Methods: A total of 316 food samples were collected using a cross-sectional study design from September 2003 to
April 2004. The techniques recommended by the International standards Organization (ISO 11290-1, 1996) and the
French Association for Standardization (AFNOR, 1993) were employed for the isolation and identification of Listeria
species. Serotyping of Listeria monocytogenes was carried out at the French Authority for Food Safety (AFSSA),
Ploufragan, France.
Results: Out of the total of 316 samples examined, 103 (32.6%) were found to be positive for Listeria. Listeria
species were isolated in 69.8% (37/53), 47.5% (29/61), 43.5% (20/46), 18.6%, (8/43), 15.4% (8.52) and 1.6% (1/61) of
the pork, minced beef, ice cream, fish, chicken and cottage cheese samples respectively. Listeria monocytogenes was
detected in 5.1% of the samples analysed. It was isolated mainly from ice cream (19.6%) and pork samples (7.5%)
followed by minced beef (1.6%), fish (2.3%) and chicken samples (1.9%). The serotypes of Listeria monocytogenes
identified belonged to 1/2b, 4b and 4e. In addition to Listeria monocytogenes, other Listeria species identified were
Listeria (L). innocua (65%), L. seeligeri (8.7%), L. welshimeri (6.8, L.murrayi (L. ivanovii and L. grayi (each 0.9%).
Conclusion: This study demonstrated the widespread occurrence and distribution of L. monocytogenes and other
Listeria species in retail meat and milk products in Addis Ababa, Ethiopia. [Ethiop.J.Health Dev. 2004;18(3):208-
212]