The examination for L. monocytogenes must be carried out both on equipment with food contact and in production areas without direct contact. Particularly hard-to-reach areas, porous, uneven materials, water accumulations (e.g. drains), and equipment and devices that are difficult to clean, where food residues can accumulate, should be taken into account. Swab and sponge samples are suitable for sampling. To increase the likelihood of detection, sampling should be done during processing, i.e., before cleaning and disinfection.
Raw material examinations, intermediate and final product controls can also be part of Listeria monitoring.