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Vegetables are highly perishable and consequently have a very short postharvest life. This characteristic, combined with improper handling during harvest, transportation and sale, generates significant losses of these products in Mozambique. This means that the quantity and quality of the products that reach the consumer are reduced. Horticultural products, such as vegetables, are formed by plant cells that remain alive after harvest and release energy. This energy comes from the transformation of substances present in plant tissue. The speed at which these transformations occur is directly linked to the post-harvest life of these products.
Vegetables are highly perishable and consequently have a very short postharvest life. This characteristic, combined with improper handling during harvest, transportation and sale, generates significant losses of these products in Mozambique. This means that the quantity and quality of the products that reach the consumer are reduced.
Horticultural products, such as vegetables, are formed by plant cells that remain alive after harvest and release energy. This energy comes from the transformation of substances present in plant tissue. The speed at which these transformations occur is directly linked to the post-harvest life of these products.
Post-harvest handling practices are as important as cultivation practices. There is no point in using modern agricultural technology to increase food production if it is not properly used by the workers. Many problems related to the sharp loss of quality and deterioration of food are the result of successive and cumulative damages suffered during their different stages of handling, storage, and transport.
In the case of vegetables intended for consumption, there is also the aggravating factor that their quality cannot be improved but only preserved and up to a certain limit.
Therefore, the careful handling of vegetables must start in the field, specifically at the time of harvest, and extended until the time of consumption.
Definition and classification of vegetables
The botanical or morphological definition of vegetables is not sustainable due to the large number of organs or reproductive states of the vegetables, as well as due to the existence of different botanical families, which have a specific climate nature, that is, some are produced only in regions of tropical climate, while others are in a temperate climate.
There is a controversy regarding certain groups of plants. For example, melon can be considered as a fruit because it is used as such; however, horticulturists and producer
classify it as a vegetable. Dried pods are produced and marketed as grains, but when consumed fresh (beans, peas) they are considered vegetables.
In a generic definition, it can be said that vegetables are parts of plants that do not belong to the group of fruits and cereals and that are consumed fresh, raw, or processed. Or, they can also be considered as a set of plants grown in vegetable gardens. Some are erroneously designated as vegetables, which botanically is the designation for a type of dried fruit.
Many schemes or group systems are used for vegetables, however, they are incomplete due to the diversity of products. A systematic classification would be desirable, as it facilitates the study of their behavior more efficiently. In general, vegetables can be grouped into four different categories of organs or parts of the plant:
● Seeds and pods
● Bulbs, roots, rhizomes and tubers
● Flowers, sprouts, stems and leaves
● Fruits
Some products botanically classified as fruits are commonly listed as vegetables and can be harvested immature, mature or ripe. For example, okra, cucumber, eggplant, tomato, pea, bell pepper, zucchini, pumpkin, melon, etc.
Simple solutions applied to the preservation of vegetables
Some practices that can assist in the selection and storage of food are:
Check the characteristics of the foods selected, as well as the seasonality, as it is a very important factor in determining the quality of the products, the flavor and the price;
Vegetables, after disinfection and drying, must be stored under refrigeration at 5°C for a maximum of three days. If intact, fruits and vegetables should be stored at room temperature. There is no need to keep them wrapped in newspapers and plastic bags. If it is necessary to pack a pre-cut fruit, for example, it is recommended that it be stored under refrigeration in glass containers at 5°C;
For better preservation in the refrigerator, it is advised that ready-to-eat foods are placed on the upper shelves, semi-ready and pre-prepared on the middle shelves and raw or non-sanitized products on the lower shelves, separated from each other and from other products.
Transport
Transporting fresh vegetables in a country such as Mozambique is a significant challenge, given that roads are often in precarious situations and it is not possible to have all the necessary inputs to maintain the quality obtained in the field.
The complete inspection of the containers that will hold the vegetables and of the carrier units must be carried out before the product is loaded. Inspections to verify the presence of bad smell, visible dirt or organic matter residues must also be carried out periodically. Vegetables are usually transported in open trucks covered with tarpaulin or, more rarely, in a refrigerated system. In the case of refrigerated transport, it is important to remember that companies also transport other materials. The best scenario would be that the vegetable transport chambers be suitable for food, only used to transport the same type of food and thoroughly cleaned between shipments. However, it is important to emphasize that each person responsible for the shipment of fresh vegetables should seek to know what type of product was previously transported in the chambers intended to transport their product. Vegetables should not be transported in containers used to transport fish, raw meat, eggs, and other products that constitute predominant sources of food-borne pathogens, unless these containers have been properly cleaned and disinfected.
In situations close to ideal, it is recommended that the transport unit be cleaned and sanitized after each transport. However, transport companies have other priorities and may not be willing to comply with the requirements for the transport of fresh agricultural products.
Among other factors, the following points should be observed in vegetable transport units:
- Visible dirt and other food particles must be systematically eliminated;
- An indication of microbiological contamination and unsatisfactory cleaning practices is the presence of foul odors;
- Transport units should not contain any water condensation and should not be wet;
- The transport chambers must allow the sealing of access to the cargo, thus avoiding environmental contamination;
- The refrigeration system must be operating for those vegetables that require refrigeration during transport;
- It is advisable to install devices that allow the monitoring of the temperature during transport, thus avoiding problems in the reception and disposal of the cargo.
Vegetables should not be placed in units that have previously been used for the transport of animals, raw food or chemical substances until appropriate cleaning and disinfection measures have been taken. Units must be washed and decontaminated by applying similar procedures to those described for food processing equipment. The same solutions indicated for disinfection can be used, provided they do not cause corrosion of the unit.
The transport of vegetables under the ideal conditions of temperature and relative humidity extends the shelf life and maintains the intrinsic characteristics of physical and sensory quality, making them more attractive. In addition, keeping a low temperature during transport can also inhibit the growth of pathogens.
As there are vegetables that are susceptible to the physiological disorder known as cold injury, transport at excessively low temperatures can damage the product. In addition to temperature, relative humidity in the transport unit must be considered to avoid dehydration or condensation development.
For long distances, as mentioned above, automatic temperature recording is recommended. In such systems, temperature recorders are placed inside the containers where the products are packaged, in the place of shipment.