Heat, chilling, and freezing injuries can significantly impact the quality, shelf life, and safety of fruits and vegetables.
Heat Injury
Heat injury occurs when fruits and vegetables are exposed to temperatures higher than their tolerance levels, often during storage or transportation.
- Symptoms: Symptoms can include sunburn or sunscald, cooking effects, and internal breakdown. For example, tomatoes might develop uneven ripening and sunburn, while apples could show internal browning.
- Causes: Prolonged exposure to high temperatures, inadequate ventilation, and direct sunlight.
- Prevention: Proper shading, cooling, and ventilation during storage and transportation, and maintaining an appropriate temperature throughout the supply chain.
Chilling Injury
Chilling injury happens when fruits and vegetables are exposed to temperatures lower than their optimum storage temperature but above freezing.
- Symptoms: Symptoms include surface pitting, browning, water-soaked areas, off-flavors, and increased susceptibility to decay. For instance, bananas can develop dark skin, and cucumbers may show pitting and decay.
- Causes: Cold storage temperatures unsuitable for the specific fruit or vegetable, often occurring during transportation or storage.
- Prevention: Understanding the specific chilling sensitivity of each type of produce and avoiding exposure to chilling temperatures. Implementing controlled atmosphere storage can help mitigate this risk.
Freezing Injury
Freezing injury occurs when fruits and vegetables are exposed to temperatures below their freezing point, leading to the formation of ice crystals inside the cells.
- Symptoms: Symptoms include cellular breakdown, mushiness, discoloration, and loss of flavor and nutritional quality. Strawberries might become mushy and lose flavor, while leafy greens can turn black and slimy.
- Causes: Storage or transportation at temperatures below the freezing point of the specific produce.
- Prevention: Maintaining storage temperatures above the freezing point for each type of produce, and using appropriate insulation and temperature control during transportation.
General Recommendations
- Optimal Storage Conditions: Each fruit and vegetable has a specific temperature and humidity range that is optimal for its storage. Maintaining these conditions is crucial to prevent heat, chilling, and freezing injuries.
- Temperature Monitoring: Regular monitoring of temperature and humidity levels in storage and transportation facilities can help detect and correct deviations before they cause damage.
- Training: Educating those involved in the supply chain, from harvest to retail, about the specific needs of different types of produce can help prevent temperature-related injuries.