Palcam Agar was developed by Van Netten et al in 1989 as an improved selective differential medium for the isolation of Listeria monocytogenes from food, clinical and environmental specimens.
Improved selectivity is achieved by the combination of antibiotic supplements and microaerobic incubation, whilst the double indicator system of aesculin hydrolysis and mannitol fermentation aids differentiation of Listeria spp from enterococci and staphylococci which can be confused with Listeria spp on other types of culture media.