Humidity problems in the meat processing industry

News vom 05.02.2014

In the meat processing industry, the use of cold technology is essential. The cooling of air leads to another physical phenomenon, namely an increase in the Relative Humidity (RH) in the area.


Many micro-organisms thrive in an environment with a high RH. It is therefore no surprise that in addition to room temperature, the relative humidity is also registered during the actual processing. In the future, it is likely that in addition to temperature regulation, facilities will also have to be introduced to permit regulation of the RH.


Slicing and processing area

The cleanroom technology employed in the pharmaceutical industry for decades is now being increasingly deployed in the meat processing industry. The trend is for more smaller slicing rooms to be built, all fitted with high efficiency filters. By keeping these areas as small as possible, the risk of contamination can be considerably reduced and flexibility increased. The deployment of personnel in these areas is limited as far as possible.

Given that the purchase of the cleanroom is accompanied by considerable investments, these areas will enjoy optimum utilisation, and a range of products will be processed during several shifts, which in turn means that cleaning will have to be carried out regularly. Sometimes, such cleanrooms have to be wet-cleaned no less than six times in a single day. As a consequence, the RH in these rooms will always be too high.

During production, walls, ceiling and equipment will become moist and wet, which is clearly not good for hygiene. In addition, the direct evaporators or cold batteries will condensate and become frozen, at which point they will have to be defrosted, which in turn can lead to capacity problems. The 'wet' cold batteries are also known as breeding grounds for a whole range of fungi and bacteria. Furthermore the meat/ sausage which is placed in the slicing room at a lower temperature will immediately condensate and in many cases a layer of 'frost' will forni on the outside of the product. Following cutting, the product, including the unwanted condensation, is then packed.



Practically all newly-built slicing rooms are today fitted with an air dehumidifying system. The temperature and filtration are provided by fitting each room with its own conventional air treatment unit. This installation regulates the temperature in the room. The centrally-installed air dehumidification system ensures that the processing rooms remain below a specified relative humidity, during production.

The air dehumidification system is regulated in such a way that no condensation occurs on the product, walls or ceiling, and that no condensation or frosting occurs on the cold batteries of the air treatment unit. Following the cleaning of the area, the cooler of the air treatment unit is switched off and the second stage heater of the unit switched on. This very dry air from the air humidifier is thus heated, which considerably increases the drying effect. Within an acceptable time, the room can then be dried.

The air dehumidification installation also functions as an air washer, which captures and eliminates between 70 and 90% of all air-borne micro-organisms. The room is maintained at overpressure, and the required outside air for this purpose is also treated by the air dehumidifier, and all air-borne micro-organisms are removed.

In practice, a number of other advantages also occur:

  1. The RH is lower (comparable with a dry winter day) as a consequence of which there are less staff complaints of “cold draughts".

  2. Less disruptions to electronic systems/ displays sensitive to damp.

  3. Air quality improvement (not only for the product but also for the personnel).

  4. Optimum utilisation of cooling capacity (practically no defrosting cycle required).


In the summer, there is considerable moisture infiltration, which concentrates on the cold batteries, which then switch to defrosting cycle (heating). This heat burden then has to be recooled by means of a temperature reduction, which in turn leads to a temperature reduction in the battery and thus more condensation and freezing, etc., etc.


  1. No wet floors, thus positive for safety.

  2. Results in considerable energy savings (on average 40% as compared with conventional systems). Also for meat/ sausage drying, this can generate considerable savings (24 hour per day energy saving).

  3. Improvement in quality/ shelf life of product.

  4. Improvement in service life of filters (no wet filters, less growth of micro-organisms in filters).

  5. Also suitable for use in freezing and refrigeration rooms.