OCCURRENCE OF SALMONELLA SPECIES IN FRESH EGGS PURCHASED FROM UMUAHIA METROPOLIS

REFERENCES 

 

Table                       Title       Page

 

Poultry products especially eggs and egg products are nutritive food items and a vital constituent of human food. They are rich in Protein, Phosphorus, Selenium, Choline, riboflavin and vitamin B 12 (Shahzad et al., 2012). Poultry is essential to the welfare of human beings. Several constraints such as diseases, poor husbandry, low productivity and shortage of feed affect the optimal performance of this industry. The poultry industry is vulnerable to a wide range of food-borne illness such as salmonellosis which is responsible for thousands of death globally and billions of loss of revenue to the poultry industry (Pegues et al., 2005). Eggs that are improperly handled can be a source of food-borne diseases, such as salmonellosis. Foods of animal origin especially poultry and poultry products including eggs, have been consistently implicated in sporadic cases and outbreaks of salmonellosis (Arif, 2013; Zancan et al., 2000).

Most human illness associated with egg consumption are from Salmonella enteritidis. Salmonella cause illness in human as well as in animals. Most Salmonella serotypes are naturally occurring in food animals (Cook et al., 2004). Salmonella species have been considered one of the most important food borne pathogens around the world. Animals are the principal reservoirs of this pathogen (Winfield and Groisman, 2003), and foods with animal source such as beef, poultry meat, egg and milk have been proven to carry these pathogen (Gillespie et al., 2003). Poultry products have been recognized as a major source of human illness caused by these pathogens and several outbreaks have been reported where eggs were the source of human infection (Crespo et al., 2005). Particularly, undercooked or raw eggs are at a high risk for humans. Among food-borne bacterial zoonotic diseases, salmonellosis causes huge economic loss in terms of massive mortality and morbidity (Hafez, 2011).

Chicken can be infected with many different serovars of Salmonella. Among these paratyphoid Salmonella, infections due to Salmonella typhimunium; Salmonella enteritidis, Salmonella Heidelberg, are of wide-world distribution with wide host range and are of major economic and public health significance (Gast, et al.,2003). Poultry has been widely acknowledged to be a reservoir for Salmonella. Eggs content may be contaminated with Salmonella by two (2) routes: transovarian (vertical transmission) or trans-shell (horizontal transmission). In the former, Salmonella enteritidis is introduced to the egg from infected ovaries or oviduct tissue before the hen lays the egg. The possibility of S. enteritidis reaching the yolk contents through the oviduct and consequently contaminating the albumin cannot, however be ruled out (Braden, 2006). Horizontal transmission is usually derived fecal contamination that penetrates the egg shell. These organisms may be able to contaminate egg contents by migration through the egg shell and membranes. Such a route is facilitated by moist egg shells, storage at ambient temperature and shell damage (Arif, 2013).

Salmonella is a rod-shaped, motile, aerobic and facultative anaerobe, non-spore forming, non-capsulated Gram-negative organism which causes salmonellosis. Salmonellosis causes an abdominal pain, inflammatory diarrhea and vomiting in patients (Gilbert et al., 2001). The organism is heat sensitive and can be readily destroyed at pasteurization temperature. Salmonella isolation by conventional culture methods are based on non-selective pre-enrichment followed by selective enrichment and plating on selective and differential culture media (Van Kessel et al., 2003).

The control of Salmonella could be difficult because there are numerous potential source of salmonella contamination in an integrated poultry operation, including chicks, feed, insects, transportation and farm environment. It may be difficult for farmers to identify chickens that have acquired recent infection with Salmonella enteritidis and that are at risk of producing contaminated eggs (Parker et al., 2002). Outbreaks and sporadic cases of salmonellosis are frequently associated with the intake of infected hen eggs. Therefore, awareness of the prevalence of Salmonella specie is essential to initiate a control programme.

This study was performed to check the occurrence and prevalence of Salmonella species in the egg shell and content of raw eggs within Umuahia metropolis as a possible cause of gastroenteritis (salmonellosis)