In
agriculture
Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peop ...
, postharvest handling is the stage of
crop
A crop is a plant that can be grown and harvested extensively for profit or subsistence. When the plants of the same kind are cultivated at one place on a large scale, it is called a crop. Most crops are cultivated in agriculture or hydropo ...
production immediately following
harvest
Harvesting is the process of gathering a ripe crop from the fields. Reaping is the cutting of grain or pulse for harvest, typically using a scythe, sickle, or reaper. On smaller farms with minimal mechanization, harvesting is the most lab ...
, including cooling, cleaning, sorting and packing. The instant a crop is removed from the
ground
Ground may refer to:
Geology
* Land, the surface of the Earth not covered by water
* Soil, a mixture of clay, sand and organic matter present on the surface of the Earth
Electricity
* Ground (electricity), the reference point in an electrical c ...
, or separated from its parent
plant
Plants are predominantly Photosynthesis, photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all curr ...
, it begins to deteriorate. Postharvest treatment largely determines final quality, whether a crop is sold for
fresh consumption, or used as an ingredient in a
processed food
Convenience food, also called tertiary processed food, is food that is commercially prepared (often through processing) to optimise ease of consumption. Such food is usually ready to eat without further preparation. It may also be easily p ...
product.
Goals
The most important goals of post-harvest handling are keeping the product cool, to avoid moisture loss and slow down undesirable
chemical
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wit ...
changes, and avoiding physical damage such as
bruising, to delay
spoilage.
Sanitation
Sanitation refers to public health conditions related to clean drinking water and treatment and disposal of human excreta and sewage. Preventing human contact with feces is part of sanitation, as is hand washing with soap. Sanitation syste ...
is also an important factor, to reduce the possibility of
pathogen
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a ger ...
s that could be carried by fresh produce, for example, as residue from
contaminated washing water.
After the field, post-harvest processing is usually continued in a
packing house. This can be a simple shed, providing shade and running water, or a large-scale, sophisticated,
mechanised
Mechanization is the process of changing from working largely or exclusively by hand or with animals to doing that work with machinery. In an early engineering text a machine is defined as follows:
In some fields, mechanization includes the ...
facility, with
conveyor belts,
automated
Automation describes a wide range of technologies that reduce human intervention in processes, namely by predetermining decision criteria, subprocess relationships, and related actions, as well as embodying those predeterminations in machines ...
sorting and packing stations, walk-in
coolers and the like. In mechanised harvesting, processing may also begin as part of the actual harvest process, with initial cleaning and sorting performed by the harvesting machinery.
Initial post-harvest storage conditions are critical to maintaining quality. Each crop has an optimum range of storage temperature and humidity. Also, certain crops cannot be effectively stored together, as unwanted chemical interactions can result. Various methods of high-speed cooling, and sophisticated
refrigerated and atmosphere-controlled environments, are employed to prolong freshness, particularly in large-scale operations.
Postharvest shelf life
Once harvested, vegetables and fruits are subject to the active process of degradation. Numerous
biochemical processes continuously change the original composition of the
crop
A crop is a plant that can be grown and harvested extensively for profit or subsistence. When the plants of the same kind are cultivated at one place on a large scale, it is called a crop. Most crops are cultivated in agriculture or hydropo ...
until it becomes unmarketable. The period during which consumption is considered acceptable is defined as the time of "postharvest shelf life".
Postharvest shelf life is typically determined by objective methods that determine the overall appearance, taste, flavor, and texture of the commodity. These methods usually include a combination of
sensorial,
biochemical, mechanical, and
colorimetric
Colorimetry is "the science and technology used to quantify and describe physically the human color perception".
It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color ...
(
optical
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultrav ...
) measurements. A recent study attempted (and failed) to discover a biochemical
marker
The term Marker may refer to:
Common uses
* Marker (linguistics), a morpheme that indicates some grammatical function
* Marker (telecommunications), a special-purpose computer
* Boundary marker, an object that identifies a land boundary
* Marke ...
and
fingerprint methods as indices for freshness.
Postharvest physiology
Postharvest physiology is the scientific study of the
plant physiology
Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. Closely related fields include plant morphology (structure of plants), plant ecology (interactions with the environment), phytochemistry (bi ...
of living plant tissues after picking. It has direct applications to postharvest handling in establishing the storage and transport conditions that best prolong shelf life.
An example of the importance of the field to post-harvest handling is the discovery that ripening of fruit can be delayed, and thus their storage prolonged, by preventing fruit tissue respiration. This insight allowed scientists to bring to bear their knowledge of the fundamental principles and mechanisms of respiration, leading to post-harvest storage techniques such as cold storage, gaseous storage, and waxy skin coatings.
See also
*
Post-harvest losses (fruit and vegetables)
Post-harvest losses of vegetables and fruit occur at all points in the value chain from production in the field to the food being placed on a plate for consumption. Post-harvest activities include harvesting, handling, storage, processing, pack ...
*
Post-harvest losses (grains)
Grains may be lost in the pre-harvest, harvest, and post-harvest stages. Pre-harvest losses occur before the process of harvesting begins, and may be due to insects, weeds, and rusts. Harvest losses occur between the beginning and completion of ...
References
External links
''Postharvest Biology and Technology''Journal ()
Writtle Postharvest Unit; Research & TrainingPostharvest Technology Research & Information Center
*
Lopez-Camelo, Andres. Manual for the preparation and sale of fruits and vegetables – from farm to market. FAO, Rome 2004
FAO Information Network on Post-harvest Operations INPho
{{Horticulture and Gardening
Horticulture
Crops
Harvest