Post-harvest losses (vegetables)
Post-harvest losses of vegetables and fruits occur at all points in the value chain from production in the field to the food being placed on a plate for consumption.
Occasionally, losses may be 100%, for example when there is a price collapse and it would cost the farmer more to harvest and market the produce than to plough it back into the ground.
[3] There are numerous factors affecting post-harvest losses, from the soil in which the crop is grown to the handling of produce when it reaches the shop.
Lack of plant food can affect the quality of fresh produce, causing stunted growth or discoloration of leaves, abnormal ripening and a range of other factors.
Increase in normal physiological changes can be caused by high temperature, low atmospheric humidity and physical injury.
[7] Such injury often results from careless handling, causing internal bruising, splitting and skin breaks, thus rapidly increasing water loss.
Fungal and bacterial diseases are spread by microscopic spores, which are distributed in the air and soil and via decaying plant material.
Their eating quality suffers if they are harvested before fully ripe as their sugar and acid content does not increase further.
Early harvesting is often carried out for export shipments to minimise loss during transport, but a consequence of this is that the flavour suffers.
In commercial fruit marketing the rate of ripening is controlled artificially, thus enabling transport and distribution to be carefully planned.
Resultant damage can include splitting of fruits, internal bruising, superficial grazing, and crushing of soft produce.
Although a few commodities are tolerant of slight freezing, bad temperature control in storage can lead to significant losses.
Breakdowns of vehicles can be a significant cause of losses in some countries, as perishable produce can be left exposed to the sun for a day or more while repairs are carried out.
Arrival of fresh supplies in a market may lead to some existing, older stock being discarded, or sold at very low prices.
There is also a wide range of post-harvest technologies that can be adopted to improve losses throughout the process of pre-harvest, harvest, cooling, temporary storage, transport, handling, and market distribution.
[10][11] In recent years, researchers have developed digital means to monitor, optimize, and make changes in the management, logistic, and post-harvest supply chain processes to improve quality and reduce food losses.
By coupling input-sensed data with already existing mechanistic models, the actionable output of an entire shipment of fresh produce, including shelf life, thermal injury, microbial spoilage, weight loss, and overall product quality can be identified.
Although still in its early stages of application in post-harvest technology, digital twin also helps identify when and where these changes occur in the entire food supply chain.
[3][14] There are no reliable methods for evaluating post-harvest losses of fresh produce although techniques for this have been improving in recent years.
