Detection and quantification of Salmonella on chicken egg shell by real time PCR

Quantification of Salmonella on chicken eggs collected from selected poultry farms and marketing channels located in and around Bareilly was carried out using RT-PCR targeting invA gene of Salmonella. RT-PCR conditions were standardised optimizing reaction efficiency and R-2 value and the specificity of the desired amplified product was assessed using melting curve analysis which was found to be 82 degrees C for Salmonella. Out of 200 chicken eggs, 8 (4%) were positive for Salmonella. Out of 100 eggs which were collected from poultry farms, 3 (3%) eggs were positive for the Salmonella while out of 100 eggs from marketing channels, 5 (5%) eggs were found positive for the Salmonella. The level of Salmonella cells per egg was higher (2.186 x 10(4) to 3.039 x 10(6) CFU/egg) in positive eggs collected from marketing channels than eggs collected from poultry farms (2.08 x 10(3) to 3.62 x 10(3) CFU/egg). The results indicated RT-PCR technique as a quick and sensitive method of quantification of salmonella on chicken egg shell surface.