precooling

Precooling is a postharvest process that rapidly lowers the temperature of harvested products, such as fruits, vegetables, meat, and seafood, to near refrigeration levels before storage or transport. The aim is to slow respiration and enzymatic activity, suppress microbial growth, and preserve texture, color, and nutritional quality as the product moves through the cold chain.

Common precooling methods include air precooling (forced-air or blast chilling), which circulates cold air around the product; hydro-cooling or water immersion, where products are submerged in chilled water; hydro-vacuum precooling, a combination of immersion with vacuum; and vacuum precooling, which uses evaporative cooling in a sealed container to remove heat. The choice of method depends on product type, packaging, desired shelf life, and resource considerations such as water availability. Temperature targets typically range from just above freezing to about 5 C, depending on commodity.

Applications are widespread in postharvest handling and distribution, particularly for leafy greens, berries, herbs, and other fresh produce, as well as some seafood and prepackaged products in processing facilities and distribution centers. Precooling is often implemented to shorten time at higher temperatures after harvest and before packaging, helping to protect quality and extend shelf life.

Benefits and considerations include reduced waste, improved appearance and texture, and longer shelf life, alongside lower metabolic rates and slower microbial growth. Precooling requires appropriate equipment, energy and water resources, and robust sanitation to prevent cross-contamination. Some commodities may experience moisture gain or loss, and economic feasibility depends on product value, volume, and logistics.