What are perishable agricultural products?

Perishable foods, such as fruits and vegetables, dairy, fish, and meat products, have a limited shelf life after harvest or production.

A “perishable agricultural commodity” is any fresh fruit or vegetable, whether or not frozen or packed in ice, and includes cherries in brine, as defined by the USDA Secretary. 7 U.S.C. The Perishable Agricultural Commodities Act (“PACA”), 7 U.S.C. §§ 499a-499t, was enacted in 1930 to regulate the marketing of perishable agricultural commodities in interstate and foreign commerce.

Perishable agricultural products are the products that not last long it includes the vegetables and fruits. The perishable products, because of their high moisture content, are inherently more liable to deteriorate, especially under tropical conditions. For each perishable food item, there is a specific time for which it will retain a predefined acceptable level of quality, defined as its ‘shelf life,’ under specific conditions of handling and storage.

Fruits and vegetables provide basic food and nutritionally essential vitamins and trace elements and, moreover, have an important role in improving food flavor and acceptability.

Vegetables and fruits are a living and respiring product that also senesce and dye after harvest. Freshly harvested fruits and vegetables are mostly comprised of water with most having 90 - 95% moisture content. Water loss after harvest is one of the most serious post-harvest conditions.

Perishable products such as fruit and vegetables continue to metabolize and respire after harvest. This means that the oxygen (O₂) in the atmosphere is being consumed producing heat, carbon dioxide (CO₂), moisture and possibly ethylene gas. As a result, the produce ripens and the quality degrades. The rate of deterioration varies greatly between individual produce depending on their overall rate of metabolism. On the other hand, many volatile compounds evolved by the produce may accumulate in the storage system.

Absence of farm storage facility and proper pack house/packing station results in the perishable produce being marketed immediately after harvesting without primary processing and adequate packaging.
What are perishable agricultural products?

Perishable crop

The perishable crop are the crops that not last long it includes the vegetables and fruits. The perishable crops, because of their high moisture content, are inherently more liable to deteriorate, especially under tropical conditions. Fruits and vegetables provide basic food and nutritionally essential vitamins and trace elements and, moreover, have an important role in improving food flavor and acceptability.

Vegetables and fruits are a living and respiring product that also senesce and dye after harvest. Freshly harvested fruits and vegetables are mostly comprised of water with most having 90 - 95% moisture content. Water loss after harvest is one of the most serious post-harvest conditions.

Fresh horticultural produce is highly perishable with some estimates suggesting a postharvest loss of 30 to 50% in fruits and vegetables. The loss occurs due to poor pre-production and post-harvest management as well as lack of appropriate processing and marketing facilities. These losses have several adverse impacts on farmer income, consumer prices and nutritional quality of the produce.

Absence of farm storage facility and proper pack house/packing station results in the perishable produce being marketed immediately after harvesting without primary processing and adequate packaging.

Poor control of storage conditions, storage for too long and inappropriate storage conditions for a particular commodity will result in poor quality product. Fruits and vegetables are living biological systems and they deteriorate after harvest. The rate of deterioration varies greatly between individual produce depending on their overall rate of metabolism. On the other hand, many volatile compounds evolved by the produce may accumulate in the storage system.
Perishable crop

Process of canning effects on vegetables

From the textural standpoint, vegetables may be divided into those that are eaten raw and valued primarily for their crispness, those that are eaten cooked and valued for their softness and those that can be consumed in either form such as cauliflower and carrots.

Vegetables like peas, beans, greens are sometimes canned. The retention of original color is of great importance effecting the marketability and consumer response.

In the process of canning, vegetables are heated to destroy spoilage disease causing microorganisms.

Such heat treatments also produce a number of of undesirable chemical and textural changes in the vegetables. The textural changes are due to partial destruction of the cell wall and cell membrane.

Blanching, plus the strong heat treatments applied to nonacid vegetables, appears to be responsible for the large vitamin losses in canning.

Heat treatments also cause chemical alteration of the green pigment chlorophyll, thus resulting in a processed vegetable with less green color.

During canning chlorophyll gets converted to pheophytin due to the high temperature used. Sometimes to retain the color and to neutralize the acid, alkali is added.
Process of canning effects on vegetables

Pest Control of Fruits and Vegetables

Pest Control of Fruits and Vegetables
Insects, rodents, plant disease, and weeds can devastate food crops, and human history is filled with famines attributable to these scourges. Large scale agricultural production tends to increase the susceptibility of crops to these hazards. Pesticides are currently an integral component of an agricultural system that produces increased yields of fresh fruits and vegetables with good visual quality. Pesticides have become a major cost of production of fruit and vegetable farmers. The use of pesticides is associated with risks of increase pest resistance, environmental contamination, exposure to farm workers, and escalating costs. With mounting regulatory pressure on pesticides it is likely that fewer compounds will be available to the farmer and that these compounds will be available for only a few crops of high economic value.

Damage to fruits and vegetables by pests is not limited to loss of visual quality. Insects and rodents can inoculate plants in the field with microorganisms that can present a health hazard, particularly if the product is not properly washed and is eaten raw. These dangers are compounded if untreated animal wastes such as manure, a potent source of human pathogens, are used for fertilization, particularly with vegetables grown close to the ground. Mold, which can be held in check by fungicide, can infect fruits and vegetables products. Mycotoxins produced by molds, such as patulin in apple products and ochratoxin in citrus fruits, present additional concern. The potential danger of these naturally occurring mycotoxins has been documented but the practical implications of decreased fungicide use are not clear.
Pest Control of Fruits and Vegetables

Shelf life of a product

The perception of quality of a product also depends on its form-fresh, frozen, canned or dried. Processing of fruits and vegetables extends the season of a perishable crop. Heat preservation (canning) provides a shelf-stable product, but usually at the cost of color, flavor, and texture. 

Better sensory quality is obtained in frozen foods but at a cost if increased energy requirement to maintain them, in a frozen state. Dried fruit products such as raisins and prunes offer very different attributes than their fresh counterparts. The consumer judges canned products with a different set of criteria than frozen or fresh items of the same commodity. 

Fresh fruits and vegetables are perishable, i.e., they have limited shelf life. They are living, respiring tissue that is also senescing and dying. Certain fruits such as bananas and tomatoes will ripen after harvest, developing desirable color, texture, and flavor during handling and storage. All other fruits and vegetables such as oranges, grapes, cucumbers, and carrots will show little or no improvement in quality within the postharvest system. 

Packing and handling systems have been developed to move the product from farm to consumer expeditiously to minimize quality degradation. Techniques used to extend shelf life of fresh products include 

Lowering the temperature to slow respiration and senescence 

Maintaining an optimal relative humidity to slow water loss without accelerating decay 

Adding chemical preservatives to halt physiological and microbial losses 

Maintaining an optimal gaseous environment to slow respiration and senescence

Longer shelf life can also be obtained by selecting cultivars that are more able to withstand the rigors of the handling system and by harvesting a crop at optimal maturity for storage and handling. 

Shelf life of a product

Chemical composition of fruit and vegetable

Chemical composition of fruit and vegetable
The primary chemical constitution in mist freshly harvested fruits and vegetables are water, which ranges s from low of 65% (fresh weight) in persimmons to a high of 96% in cucumbers.

Fruit and vegetables tend to be low in protein and lipids and high in carbohydrates.

They are also rich sources of certain micronutrients such as specific vitamins and minerals.

The only major fruits and vegetables with a relatively high lipid content are avocado and the olive, both which contain up to 15% lipid, oilseeds such as cottonseed, palm, peanut, and soybean are not usually considered fruits and vegetables.

These lipids primarily occur as components of cell membranes which function to maintain the integrity of cells and theirs organelles, as well as to serve as the staging area for many critical metabolic reactions.

The fatty acid components of membrane lipids tend to be relatively unsaturated.
Chemical composition of fruit and vegetable