Evaluation of two commercial methods for the detection of Listeria sp and Listeria monocytogenes in a chicken nugget processing plant

This study measures the detection performances of two rapid test systems (Listeria Rapid Test Clearview(TM) and Bax(TM) system) for the screening of Listeria sp. and Listeria monocytogenes, respectively. A total of 413 samples from different sources (product from (i) different stages of processing, (h) different environments, and (iii) different food handlers), collected from a chicken nugget processing plant, were analysed by both rapid methods and a cultural method consisting of pre-enrichment, enrichment, and isolation onto selective agars (PALCAM, LPM, and HCLA). Overall, results showed an excellent correlation between data obtained using Clearview(TM) and the cultural method, with Clearview(TM) presenting an efficiency of 99%. Bax(TM) showed a lower correlation using the cultural method, with an efficiency of 71.1%. The type of sample did not affect the efficiency of Clearview(TM), which varied from 98.1% for product samples to 100% for environmental and food handler samples, while for Bax(TM) it had a marked influence. Efficiency of Bax(TM) varied from as high as 100% for food handlers to 37.9% for product samples.