Why can fresh vegetables lose quality after they are harvested?

Fresh vegetables are living organisms that continue their life processes after harvest, which leads to a natural decline in quality over time. Several factors contribute to this deterioration:1

• Biological Changes: Post-harvest, vegetables undergo internal changes including water loss, starch-to-sugar conversions, flavor and color shifts, toughening, and eventual softening or decay.1
• Environmental Factors: Quality is heavily influenced by air temperature, circulation, humidity, and atmospheric composition (oxygen and carbon dioxide levels). For example, improper storage temperatures can lead to chilling injury or accelerated senescence.12
• Mechanical and Biological Damage: Physical injury during harvesting can damage cells and trigger the release of ethylene, a hormone that promotes aging. Additionally, vegetables are susceptible to microbial spoilage from fungi, such as yeasts and molds, and bacteria, which thrive under certain moisture and temperature conditions.234
• Maturity: The stage of development at harvest significantly impacts shelf life; some vegetables reach peak quality before full maturity, after which they naturally begin to deteriorate.5

To maintain freshness, it is essential to slow these life processes through proper cold storage and humidity control.12