When a freshly slaughtered carcass is initially chilled to its storage temperature, it will lose weight through moisture loss to the atmosphere. Depending on the chilling process, this can be up to 3% of its overall weight. The highest losses will occur in the early stages when the temperature difference between the carcass and its surrounding chill store atmosphere is at its greatest.
By raising the humidity of the air around the carcasses to between 90-95%RH moisture loss from the meat is inhibited and weight losses can be reduced to less than 1%,
This will have an immediate impact on the profitability of an abattoir operation, as it can stop around 4kg of product evaporating from a typical side of beef during the chill down process.
As well as improving profits through reduced weight loss a higher humidity in a chill store will improve the thermal conductivity of the air. This results in the carcass reaching its storage temperature more rapidly, which in turn reduces refrigeration energy costs and inhibits microbial growth on the meat.
Benefits of humidification in abattoirs include:
- Reduction in cooling weight losses from 3% to under 1%
- Immediate increase in profitability
- Improved thermal transfer from the carcass and shorter chill cyles
- Reduced refrigeration energy costs from faster cooling
- Reduced microbial growth from faster cooling
- Extremely hygienic product design for total confidence
- Comprehensive service of advice, design, supply, installation, commissioning, maintenance and spares supply
For an abattoir processing 3,500 carcasses per week and an average cost of beef at $4/kg, this technology could increase profits by over $2M per year by preventing over 500,000kg of beef simply evaporating into its chill store’s atmosphere.
A carcass coming from the slaughter line is wet and warm. When it is introduced to the chill store, the cold dry air strips moisture from its exposed surface. The amount depends on the abattoir’s cooling technology but it can be anywhere between 1.2-2.5% of its total weight, and sometimes even more. By maintaining a high humidity in the chill store with a humidifier during the initial cooling, moisture loss from the carcass is inhibited and can be reduced to less than 1%. Independent testing has shown that by maintaining the optimum humidity during cooling, carcass weight loss is reduced without any condensation forming inside the chill store or on the meat. Humidification of the air does not introduce moisture to the surface of the carcass or increase microbial growth.
In fact, client tests showed that the high humidity actually reduced microbial growth rather than promote it. The higher humidity improved the conductivity of the air and consequently increased heat transfer from the carcass. Some installations have seen a significant reduction of their chill cycle to reach the required carcass core temperature. As the carcass temperature is reduced more rapidly the microbial growth is inhibited.
Another significant benefit of a quicker cooling cycle is the reduction in energy consumption of the cooling system. Clients have seen energy bills reduced by as much as 10% when maintaining an optimum humidity in the chill down area due to improved heat transfer efficiency from the carcasses.
The nozzles that combine compressed air and water to produce a spray that has a droplet size of just 7.5microns. The nozzle line is mounted directly in front of the evaporator coils of the refrigeration system and introduces moisture to the airstream as is enters the chill store. The extremely fine spray ensures the moisture is absorbed by the atmosphere and prevents wetting inside the room. The flow of compressed air also avoids the possibility of drips. Tiny needles inside the nozzles act as a self-cleaning mechanism and prevent blockages making the system extremely robust, requiring very little maintenance.
The humidifier has been developed with hygiene as a principal design factor making it ideal for use in food processing facilities. A reverse osmosis water filter removes all minerals from the supply water before it is treated with ultraviolet sterilization to kill any remaining microorganisms. In addition, the system will regularly run purge and flush cycles to ensure water cannot remain in the humidifier to stagnate.
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