COMPARISON OF A MICROTITRATION PLATE ELISA WITH A STANDARD CULTURAL PROCEDURE FOR THE DETECTION OF SALMONELLA SPP IN CHICKEN

A rapid antibody-capture enzyme-linked immunosorbent assay (ELISA) det ecting a wide range of Salmonella serotypes and employing only one cul ture stage was used to analyze the giblets and body cavity rinsings fr om frozen chickens. The results from the ELISA were compared with thos e obtained using a standard cultural procedure in current use in two l aboratories, Norwich (N) and Ipswich (I), of the Public Health Laborat ory Service (PHLS) in the UK. ELISAs were carried out on the same samp les at each of two PHLS laboratories and at the Institute of Food Rese arch with good agreement (94% and 90%). When compared with the cultura l method there was 80% and 70% agreement with the ELISA with the PHLS( N) and PHLS(I) samples. The ELISA appeared to have a false-positive ra te of 17% (samples from PHLS(N)) but on reculture of the ''negative'' samples this rate fell to 7%. The false-negative rate for the ELISA wa s 26% (samples from PHLS(N)) which appeared to be due to insufficient growth of the Salmonella spp. in the single cultural step employed in the ELISA rather than lack of recognition by the antibodies. The probl em of false negatives with the cultural method is also discussed. Thes e results are comparable to previously published studies relating immu noassays and the conventional procedure for Salmonella detection when analyzing similar samples. Suggestions are made as to how further incr eases in ELISA efficiency might be brought about.