Shorter: Incubating for less than 24h might not be enough to grow Listeria monocytogenes, especially if the contamination level is expected to be low. Performance, according to AOAC PTM has only been validated for a minimum of 23h. NEMIS recommends 24h or up to 72h incubation.
Longer: NEMIS has validated that a total incubation time up to 72h maintains the assay performance.
