Post-Harvest: Preserving Food Product Quality

Certain changes that occur after harvest are essential for a product to reach its desired eating quality. Many tropical and subtropical fruits such as banana, mango, and tomato are picked at their mature stage while still green; to reach eating quality, they are then ripened. This process is essential for avocado, which only becomes tender once picked from the tree.

The main factors affecting post-harvest food quality

Quality loss in a product can be caused by a range of factors, which can be grouped into four main categories:

1. metabolic factors;
2. transpiration (water loss);
3. mechanical injury;
4. microorganisms.

Metabolic factors

These are linked to normal senescence or to abnormal metabolism, the development of which leads to physiological disorders. Losses caused by these disorders are more dramatic than the effects of general senescence, which is not, in itself, a problem when storing produce and vegetables.

Transpiration (water loss)

This can lead to rapid loss of a product's quality. Severe wilting of vegetables can be caused by storing them in a dry environment. This wilting mainly affects a product's texture, and consumers are usually reluctant to buy this type of product.

Mechanical injury

This causes a loss of the product's visual quality, since these injuries leave unsightly marks on the product's surface. They also increase the product's overall metabolism, as it attempts to repair the damaged tissue. They can also lead to water loss through transpiration, especially when they damage the barriers that limit such losses. Mold growth can be rapid and can cause severe losses if all the conditions for its development are present, particularly the optimal temperature, pH, and humidity.