What technique is commonly used for preserving food quality during transport?

Refrigeration is the most effective technique for preserving food quality during transport as it helps maintain a stable, cool temperature that slows down the growth of bacteria, molds, and other pathogens that cause spoilage. By keeping food items at low temperatures, refrigeration extends their shelf life, ensures food safety, and retains flavor and nutritional value. This method is particularly important for perishable items such as fruits, vegetables, dairy products, and meats, which can spoil quickly if not properly cooled during transportation.

Other techniques like fermentation, dehydration, and pickling do help in preserving food, but they are typically applied before transportation rather than during. Fermentation involves the conversion of sugars into acids or alcohol, which can enhance flavor and preservation but often changes the food's original state. Dehydration removes moisture from food, which can help in preservation but is not practical during transport. Pickling involves preserving food in vinegar or brine, which also modifies the food's texture and taste. While these methods can be beneficial, refrigeration stands out as the primary technique used specifically for maintaining food quality during transport.