TECRA® Unique™ Test for Rapid Detection of Salmonella in Food: Collaborative Study

Abstract

The TECRA® Unique™ Salmonella test uses the principle of immunoenrichment to allow rapid detection of Salmonellae in food. A collaborative study was conducted to compare the TECRA Salmonella Unique test with the reference culture method given in the U.S. Food and Drug Administration's Bacteriological Analytical Manual. Three food types (milk powder, pepper, and soy flour) were analyzed in Australia and 2 food types (milk chocolate and dried egg) were analyzed in the United States. Forty-one collaborators participated in the study. For each of the 5 foods at each of the 3 levels, a comparison showed no significant differences (p ≥ 0.05) in the proportion of positive test samples for Unique and that for the reference method using the Chi-square test for independence with continuity correction.

Application of BAX system, Tecra UniqueTMSalmonella test, and a conventional culture method for the detection of Salmonella in ready-to-eat and raw foods

“…A validation study for the Unique TM test on orange juice indicated that there was no significant difference between the Unique TM test and the conventional standard culture method on the detection of Salmonella in 25‐g samples inoculated with one to five cells (Dailianis and Hughes 2002). Hughes et al. (2001) also reported that the Tecra Unique TM test was comparable with the standard culture method in the detection of various serotypes of Salmonella in five different food types (milk powder, pepper, soy flour, milk chocolate, and dried egg) inoculated with one to five cells per 25‐g sample.…”

“…To date, very few reports on the detection of S . Typhi in foods by rapid methods are available, although the detection of other serovars by PCR or immunoassay‐based methods have been described frequently (Hughes et al. 2001; Bailey and Cosby 2003; Uyttendaele et al.…”

“…A collaborative study conducted to evaluate the performance of Tecra Unique TM test for the detection of S . Enteritidis in dried egg also revealed that some test samples reported as negative became positive when subcultured from tube 3 broth of the modules (Hughes et al. 2001).…”

“…Following 16–20 h of sample pre‐enrichment, samples can be applied to the test module, and then the immunoenrichment and detection steps can be carried out automatically with antibody‐coated dipsticks inside the Unique Plus TM instrument. Presumptive results can be generated in <22 h, followed by confirmation of presumptive positives with culture methods (Hughes et al. 2001).…”

Novel Salmonella spp. Diagnostic Markers Based on the gyrB Gene and its Application on Food and Environmentally-Derived Water Samples

“…In chicken mince samples, the gyrB marker was also proven to be more sensitive, able to detect as few as 72 genomes in artificially contaminated samples in comparison to the threshold of 832 genomes detected with the invA marker. [42]. Sensitivity of the kits is also affected by background flora potentially resulting in false negatives [43,44].…”