Comparison between two commercial ELISAs and a culture procedure for the detection of Listeria spp.

 The efficiency of two commercial enzyme-linked immunosorbent assays (ELISAs), the Oxoid Listeria rapid test and the Tecra Listeria visual immunoassay for the detection of Listeria spp. was compared with that of a culture method. Of the 60 samples examined by ELISA and the culture procedure, Listeria was detected and confirmed by culture in 20, 34 and 44 samples by the Tecra, Oxoid and microbiological methods, respectively. The overall sensitivity of the Tecra and Oxoid tests was 50% and 93%, respectively. Both ELISAs had a specificity of 100%. The efficiency of the Oxoid test was 95%, while that of the Tecra assay was 67%. Differences in the results of the Oxoid test and those of the culture method were not statistically significant; however, the differences between the results of the Tecra assay and the culture procedure were significant. The Oxoid test was less labour intensive, less time consuming and easier to perform than the Tecra assay. It was concluded that the Oxoid test is a good alternative method to the culture procedures when screening for the presence of Listeria spp. in foods, especially when a large number of samples have to be analysed. Received: 24 June 1997