Purpose: The purpose of this study was to assess the ability of two real-time PCR assays to detect L. monocytogenes in mozzarella cheese enriched in 24 LEB Complete media.
Methods: Mozzarella cheese (n=20) was artificially inoculated with L. monocytogenes to obtain fractional recovery in 125g portions and held at 4°C for 72 hours to cold stress the target organism. Samples were homogenized with 1,125 mL pre-warmed (35°C) 24 LEB Complete media and incubated at 35°C for 22-26 hours. After incubation, all samples were analyzed by real-time PCR and confirmed using the reference culture method.
Results: The real-time PCR assays for Genus Listeria and L. monocytogenes detected all 10 culture positive samples after 22 hours of enrichment in 24 LEB Complete media.
Significance: The results of this study demonstrated no significant statistical difference between the real-time PCR detection method and the reference culture method to detect Listeria spp. and L. monocytogenes in 125g of mozzarella cheese.