Consumers rely on food processing and storage facilities to ensure the ideal environmental conditions for produce from the moment it’s picked at the field to the time it reaches a grocery store. When it comes to cold storage, humidity and temperature levels are among the most important considerations to prolong the life of fruits and vegetables. When environmental conditions are not ideal, produce deteriorates and becomes potentially harmful to consumers.
How Cold Storage Humidity, Temperatures and Air Flow and Other Conditions Affect Produce Quality
Regardless of all the pesticides and sprays used on produce, microorganisms live in nearly all natural environments. While some are beneficial, other cause fruits and vegetables to rot. Bacteria and molds that cause produce to decompose generally thrive when cold storage humidity levels and temperatures are too high. The colonies that they form can quickly spread to nearby good, making them unsafe to consume. As fungus and bacteria grow, they also produce waste that affects the way the food looks, smells, feels and tastes.
Heat on the Field
Field conditions are vital in preparing produce for storage. Some types of produce require preliminary pre-cooling before moving into cold storage to ensure appropriate moisture content and relative humidity levels. While dipping warm produce in cool water lowers its temperature, it may spread mold spores or bacteria throughout the good.
Inappropriate Refrigeration Temperatures
Each type of fruit and vegetable has a limit in regards to the “critical” temperature, or lowest temperature, it can tolerate before experiencing irreversible chill damage. A carrot that’s stored in an environment that’s too cold, for example, will soften and turn black. When placing produce in cold storage, consider the critical temperatures of each type of good to prevent produce damage and losses.
Similarly, appropriate refrigeration temperatures slow the growth of bacteria. When storage temperatures are between 41° and 135°F, the conditions may promote bacterial growth.
Inappropriate Relative Humidity Levels
Many produce items require high relative humidity levels between 80 and 95 percent, such as leeks, tomatoes, apples and lettuce. The cold storage humidity levels that are too dry lead excessive moisture losses that damage produce.
A produce’s water vapor content in relation to a storage unit’s temperature is also an important consideration. When falling temperatures cause humidity trapped in produce to reach its dew point, condensation may form on the fruit or vegetable. Localized condensation is particularly problematic because it can lead to excessive moisture that promotes microbial growth.
Insufficient Airflow in Packaging
The crates and packages in which produce is stored should not restrict airflow. To this end, a gap of 2 feet or more between walls and crates filled with produce, and a 3-foot or larger gaps between crates and ceilings, refrigeration units and other crates is ideal. When produce packaging or storage crates are too close together, moisture levels may rise because of insufficient airflow. Furthermore, if the packaging material is porous, moisture may permeate it, affecting the air quality surrounding the produce.
While cold storage humidity levels and temperatures go a long way toward ensuring the healthfulness and longevity of produce, a facility must maintain sanitary conditions. Failing to clean storage containers or allowing leaking water to accumulate, for example, promote food spoilage and the spread of harmful microorganisms.
When a cold storage facility has difficulties maintaining ideal environmental conditions despite following industry best practices regarding produce moisture content, sanitation and storage, it may benefit from the use of temporary humidity control. Polygon offers custom solutions with remote monitoring that ensure proper airflow, relative humidity levels, temperatures and safer environmental conditions for produce. Contact Polygon today to learn more and to schedule a consultation.
[Photo from rore via CC License 2.0]