The present study was planned to estimate occurrence of invasive Salmonella spp. in retail chicken supply chain of Mumbai and quantifying Salmonella at crucial stages of processing by the Most Probable Number (MPN) and confirmation by invA gene by PCR assay. A total of 18(n = 108) farm samples were found to be positive for Salmonella with prevalence of 16.66% and statistical significance was observed amongst different sources at farm (p=0.027). Highest prevalence of Salmonella spp. was noticed in litter samples (50.00%) followed by cloacal swabs (25.00%), water utensil swabs (25.00%), faeces (16.66%), water (16.66%), wall dust (8.33%) and worker hand (8.33%). Over all prevalence of Salmonella spp. amongst various samples in retail shop was found to be 19.04 %. Out of 42 different chicken retail shop samples analysed03 (7.14 %) swab samples of chopping board found positive while one sample each from water and swab samples of worker hand, platform, knife, and cloaca were found positive. Amongst 24 swab samples collected from chicken carcasses at various chicken processing stages, highest rate of contamination (50 %) was observed in post defeathering and post evisceration stages of processing with average count of 1.88 and 2.11, log MPN count/10cm2 respectively. Out of 34 Salmonella isolates obtained in this study, 31 isolates showed positive amplification of 284 bp fragment specific for the invA gene with 91.17% detection level. Thus, study revealed that poultry litter at farm and post defeathering and post evisceration stages at retail chicken processing, are critical sources of cross contamination of invasive Salmonella spp.

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