CONTAMINATION OF CHICKEN EGGSHELLS AND EGG CONTENTS WITH SALMONELLA SPECIES FROM SELECTED FARMS IN KOSGAMA, COLOMBO DISTRICT

Abstract

Salmonellosis is a common, widely distributed foodborne disease. Consumption of raw or undercooked chicken eggs infected with Salmonella has been reported in association with salmonellosis cases; however, minimum attention has been paid to regulate the quality of eggs released for consumption. This study aimed to investigate the presence of Salmonella in eggs collected from selected farms from Kosgama area and to compare the egg quality of backyard and commercial farms. Randomly purchased eggs from selected chicken farms were analyzed for the presence of Salmonella. Egg content was mixed thoroughly, and 25.0mL was inoculated into 225.0mL of 1% Buffered Peptone Water (BPW) and incubated at 35⁰C (24h). From the pre-enriched specimen, 0.1ml was added to 10.0ml of Rappaport Vassiliadis broth and incubated at 42⁰C (24h). The same procedure was followed for shells. Isolated cultures were streaked on Brilliant Green Agar (BGA) and Xylose Lysine Deoxycholate Agar (XLD) and incubated at 35⁰C for 24h. Colonies were investigated with Gram staining, biochemical tests and serotyping was carried out to identify the species. Of 78 eggs, 35 were from backyard and 43 from commercial farms. Six specimens (4 from shell and 2 from content) yielded Salmonella (7.69 %). Four of the positive specimens were from backyard farms (4/35, 8.91%) and remaining two (2/43, 3.62%) were from commercial farms. Isolates were identified as S. Typhimurium and S. Enteriditis.  The prevalence of Salmonella was 7.69 % (n=6). The proportion of Salmonella showed no significant difference (p=0.782) between backyard and commercial farms.