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Tip of the Week: How to Control Condensation in a Food Premises
Tip of the Week: How to Control Condensation in a Food Premises

Condensation is defined as water which collects as droplets on a cold surface when humid air is in contact with it. 

Water is a universal solvent meaning that it can dissolve or hold in suspension a variety of substances which could include impurities such as microorganisms, dust, pollutants, water soluble chemicals, etc.

The risk in a food premises

When condensation forms on a surface the impurities on that surface could dissolve into the water and contaminate the water. If the water falls into the product, contamination occurs.

In many cases the impurities on a surface cannot be seen by the naked eye and unless the surface on which the condensation is collecting is deemed a food contact surface and controlled as a food contact surface (i.e. is made of cleanable, food grade materials and is cleaned at least daily) then it needs to be assumed the surface is contaminated.

Condensation if left uncontrolled could also lead to mold growth.

Microbiological testing of a surface can be used to provide validation that dedicated food contact surfaces are being managed however, microbiological testing of condensate on a non-food contact surface and swabbing of non-food contact surfaces cannot be used as evidence to indicate the surface is risk free.

The science of how condensation forms

Condensation is the change of the physical state of water from a gas phase to a liquid phase. Condensation normally forms when warm moisture laden air encounters a cooler medium, which could be a solid medium or even a cooler air mass. When this occurs the moisture in air goes passed its saturation limit and becomes too heavy for the air and results in water droplets forming on a surface or precipitating in air.  

Warmer air can hold more moisture than cooler air. Frost build up in freezers is an example of frozen condensate.

How to control condensation in a food premises

Condensation in a processing plant is a complex challenge with multiple components: temperature, moisture, pressure and filtration. It is often referred to as pyschrometrics, or the science of moist air.

Some of the more common ways to control condensation include:

  1. Ventilation will reduce the amount of moisture in the air. This can be done by extracting the moisture laden air or dispersing the air by using fans or a combination of both. Fans are often used to draw warm air in and exhaust fans to pull cold air out. This can cause negative pressure and dehumidification units linked to pressure sensors may need to be used to keep this in balance.
  2. Keep equipment (e.g. cooker) that generates moisture covered if possible.
  3. Prevent temperature differentials. When warm moisture laden air suddenly cools when it contacts a cooler surface condensation occurs. This can be prevented by insulating materials, such as metal, that are very conductive with lagging (insulation) or using materials that are less heat conductive e.g. use PVC’s with a vapor barrier instead of metal. Insulation keeps a surfaces temperature at a higher level.
  4. In areas of the facility where there is a sudden change in temperature from one room to another (e.g. warm manufacturing area leading into a freezer), condensation forms as frost. This effect can be reduced by having gradual temperature changes between areas. For example, using insulated partitions or installing an ante rooms which step change the temperature between two rooms of significant temperature differences.
  5.  Another way to control condensation is to heat materials. For example, to reduce frost build up on a freezer entrance the materials around the entrance can be heated using heat tape.
  6. The use of warm or hot water to clean in a cold environment is a common source of condensation. The solution may mean pulling in outside air, conditioning the air to 50°F /10°C and re-heating the air to 80°F/27°C and pushing it into the room. Then exhaust the air from the room.
  7. Vapor barriers (materials that resist diffusion of moisture through walls, floors or ceilings) are often used in bakeries by oven exhausts.
  8. In areas where condensation is inevitable catch trays can be used to protect the product below from condensation droplets. However, be careful the catch tray does not form condensation.
  9. In certain unique situations where condensation cannot be arrested or needs to be controlled until a more permanent solution can be achieved then a process of wiping the condensation away can be considered. The frequency would need to be sufficient enough that it is done before droplets fall. Defining this area as a food contact surface to ensure it is cleaned regularly will also be needed.
Control the main factors that cause condensation: moisture, temperature, and pressure
  1. Reduce the moisture in the air either by eliminating source of moisture or dehumidifying the air
  2. Reduce temperature differentials
  3. Have good air flow and maintain positive air pressure.  Have a good balance between exhausted air and sufficient outside air to maintain a desirable air pressure

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Avatar  Ben Ablon 2 years agoReply

Most of the bakeries should use these metrics and monitor these numbers to be included in the daily inspection and routines. Thank you for this article which is truly a critical control points every staff in the food/beverage facilities and processes shall watch, measure and control in highest priority.
Ben Ablon
Elektromekanex USA

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