Evaluation of two commercial methods for the detection ofListeriasp. andListeria monocytogenesin a chicken nugget processing plant

Abstract

This study measures the detection performances of two rapid test systems (Listeria Rapid Test ClearviewTMand BaxTMsystem) 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, (ii) 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 ClearviewTMand the cultural method, with ClearviewTMpresenting an efficiency of 99%. BaxTMshowed a lower correlation using the cultural method, with an efficiency of 71.1%. The type of sample did not affect the efficiency of ClearviewTM, which varied from 98.1% for product samples to 100% for environmental and food handler samples, while for BaxTMit had a marked influence. Efficiency of BaxTMvaried from as high as 100% for food handlers to 37.9% for product samples.Key words: Listeria, Listeria monocytogenes, ClearviewTM, BaxTM.