Identification and characterization of Salmonella species in whole egg purchased from local markets in Addis Ababa, Ethiopia

Abstract

Currently, salmonellosis is one of the major food borne pathogen both in developing and developed
countries. Humans encountered this problem by consuming raw or undercooked food especially of
poultry and egg products. The objective of the study was to identify and characterize Salmonella
species in trans-ovarian contaminated eggs purchased from local markets in Addis Ababa. The study
was conducted by using a standard laboratory diagnostic procedure. Isolation of Salmonella species
from eggs was done both in solid and liquid media, and among three hundred eighty four (384) clean
and non-cracked eggs examined, twenty eggs (5.21%) were positive for Salmonella enteritidis using
selinite broth and Rappaport vassilidies broth as liquid media and xylose lysine desoxycholate (XLD)
agar, MacConkey, Salmonella Shigella agar as solid media. S. enteritidis positive eggs (n = 20) when
subjected to biochemical test using lysine iron agar (LIA) identified eighteen (4.69%) positive and two
(2) negative samples. In this research, some commercial eggs yielded a number of S. enteritidis. This
can be attributed to different causes but the most important one is transovarian transmission which
implicate the possibility of poor animal health in layer farms. Storage time/temperature play the most
significant role for its multiplication.