The examination of the total germ count from hand swabs is not a suitable parameter for assessing the hygiene status, even after cleaning and disinfection, because the natural skin flora is not removed by hygienic hand disinfection. Enterobacteria are more suitable but can still not be completely reduced, depending on individual skin structure. Depending on the operation, it may be advisable to investigate specific parameters such as E. coli or Staphylococcus aureus. It should be considered that hands can also be contaminated by contact with raw animal or plant foods.

Environmental investigations help to assess the internal hygiene status. They allow hazards to be recognized and preventive measures to be initiated for the production of hygienically impeccable food. The obligation for sampling in processing areas and equipment used in food production, especially for Listeria monocytogenes, is regulated by Art. 5 of Regulation (EC) No. 2073/2005.

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.

Listeria monitoring refers to the targeted sampling of processing areas and equipment for L. monocytogenes in a food establishment and its documentation. The goal is to detect and eliminate persistent strains of Listeria in the facility to prevent food contamination.

A regularly conducted sampling to record the company's internal hygiene status. The monitoring can include, for example, the inspection of personnel, facilities and equipment, indoor air, and water used in production.

Commercially available double-sided ready-to-use nutrient media suitable for pressing onto smooth surfaces. They are used, for example, for examining the aerobic mesophilic germ count (total germ count) and Enterobacteriaceae to check successful cleaning and disinfection according to DIN 10516. Contact samples should not be used for the specific determination of pathogenic germs. Swab and sponge samples are better suited for this purpose.

Sterile cotton swabs suitable for semi-quantitative testing for any germs in hard-to-reach areas and on non-smooth surfaces. This method allows the identification of numerous target organisms both qualitatively and semi-quantitatively.

Sponges suitable for sampling surfaces or drains. They are mainly used for qualitative examinations of pathogenic germs. According to Regulation (EC) No 2073/2005, for example, the sampling of carcasses for the examination of salmonella must be carried out using a swab sponge.

Commercially available ready-to-use culture media (contact plates) suitable for pressing onto smooth surfaces. They are generally used for the examination of aerobic mesophilic germ count (total germ count) and yeasts/molds, e.g., to verify successful cleaning and disinfection. Contact plates should not be used for the specific determination of pathogenic organisms. Swab and sponge samples are better suited for this purpose.

Environmental examinations are used to detect microorganisms in a company's production environment. They serve to check and ensure hygiene standards. Environmental examinations include the inspection of, for example, surfaces of machines, equipment, product-contact surfaces, personnel, water, and air.

Using contact and swab samples from work surfaces, devices, and objects that come into contact with food, their contamination with pathogenic germs can be determined. After cleaning and disinfection, the success of the cleaning and disinfection can thus be verified. Moreover, they can be used to check the hygiene status of the personnel.
Additionally, the quality of the water used in the company with direct and indirect contact with food can be checked, and a germ count determination of the room air can be carried out.

In practice, two methods are applied:

1. Air germ measurement with a measuring device
   A device (e.g. impaction device) is needed, which draws in a defined air volume, accelerates it and deposits it, for example, on a nutrient strip. The nutrient strip is then incubated and evaluated.
2. Sedimentation method
   Petri dishes are placed open at relevant points in the production process, then incubated and evaluated.

They are usually carried out during operation in product proximity. As a standard, the air is examined for aerobic mesophilic germ count (total germ count) and possibly additionally for yeasts/molds. In the food sector, there are no statutory guideline and limit values for this. However, regular measurements make it possible to identify changes and create trend analyses.

Airborne germ measurements can be performed to check the microbiological air quality and the functionality of ventilation systems. Air investigations are thus part of the environmental monitoring required to verify operational hygiene.