Detection of Salmonella enteritidis in eggs and chicken with enzyme-linked immunosorbent assay

An ELISA previously developed for the rapid detection of Salmonella enteritidis (SE) in environmental samples was modified and applied to food samples. A sandwich ELISA was designed that employs affinity-purified rabbit polyclonal antibodies for the capture stage and highly specific monoclonal antibodies for the detection stage. Thirty-nine species of bacteria other than SE, including 32 Salmonella species, were included in cross-reactivity testing with ELISA. Results showed no reactivity with any species tested besides SE. Salmonella enteritidis was added to homogenized food samples (chicken skin, meat, and eggs) to test ELISA sensitivity. The lower limit for ELISA detection of SE was 10(4) cells/mL for pure cultures and in 10% meat (wt/vol), 10(5) cells/mL in 10% skin (wt/vol), and 10(7) cells/mL in 10% eggs (wt/vol). Salmonella enteritidis detection with ELISA was confirmed with the Food and Drug Administration (FDA) Bacteriological Analytical Manual (BAM) method. Results were obtained within 24 h for ELISA method compared to 96 h for the BAM procedure. Results show that sensitivity of ELISA can vary with the type of food tested for detection of SE.