COMPARISON BETWEEN 2 COMMERCIAL ELISAS AND A CULTURE PROCEDURE FOR THE DETECTION OF LISTERIA SPP

The efficiency of two commercial enzyme-linked immunosorbent assays (E LISAs), the Oxoid Listeria rapid test and the Tecra Listeria visual im munoassay 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 a nd 44 samples by the Tecra, Oxoid and microbiological methods, respect ively, The overall sensitivity of the Tecra and Oxoid tests was 50% an d 93%, respectively. Both ELISAs had a specificity of 100%. The effici ency 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 b etween the results of the Tecra assay and the culture procedure were s ignificant. The Oxoid test was less labour intensive, less time consum ing 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.