Beginning postharvest training for horticultural crops


This set of online training modules is designed to support smallholder and subsistence farmers who are interested in selling their horticultural crops, by supplying fundamental postharvest concepts that will enable them to transition from small-scale production to selling their crops at markets.

Part of a three-level training series, this beginning level is aimed at farmers with little or no background or understanding of postharvest handling practices essential for selling horticultural crops. This set of lessons provides a foundation of topics including postharvest basics, sanitation, food safety, packaging and transportation.

These lessons were originally created for farmers and audiences in Latin America, but are widely applicable to small-scale farmers elsewhere in the world. 

Users can control the progression of each narrated training topic by starting and stopping lessons as well as switching between topics. Notes are also made available for each topic that can be accessed at the top control bar of the video player. 

Postharvest basics for horticultural crops

This 7-minute postharvest basics lesson presents introductory principles of postharvest handling that are important for providing safe, high quality fruits and vegetables to consumers.

One critical aspect of horticultural crops that impacts postharvest handling is that fruits and vegetables have high rates of deterioration. Techniques such as keeping produce under shade, exercising careful picking, and using clean water can help reduce deterioration and losses. Ripening and senescence, or the dying of plants, are also important to consider in postharvest practices.

Some fruits and vegetables continue to ripen after being picked, such as bananas, mangos, and apples. Other crops begin to die as soon as they are picked. This changes which practices should be taken to ensure that products arrive in time to consumers. Horticultural crops also undergo a series of physical, physiological, and biological changes and disorders that have implications for postharvest processing and losses.  

Luis Cisneros, of Texas A&M University, is the presenter of this lesson.

Sorting and grading crops

This 5-minute lesson on sorting and grading of horticultural crops discusses what consumers look for in their products and how sorting can can be done with this in mind. Knowing what consumers want in terms of taste, aesthetics, and quality standards can better inform what products are suitable to be sold in local markets. Individual markets have their own specific demands for shape, form, color, and food safety. Farmers who understand these standards can focus on harvesting their best products to be sold at the market and use products that don't meet these standards for alternative purposes such as livestock feed or compost. 

Farmers should make sure that during harvesting they are using clean materials for collection such as bins or crates, knives, gloves, bags, or other items used to gather fruits and vegetables. Local materials can be used for collection such as wooden crates, baskets made out of palm leaves, or other receptacles to ensure products are out of contact with the ground. Farmers should also identify suitable locations on the farm for collection that are clean and provide ample shade. 

Ivanna Vejarano, of the Panamerican Agricultural School, Zamorano, is the presenter of this lesson.

Quality measurement procedures

This 5-minute quality measurement lesson surveys quality factors and how they can be assessed. In order for fruits and vegetables to be sold in the market, quality must be measured to ensure products meet consumers preferences.

Measurements of quality include appearance, texture, smell, size, nutritional value, and taste. Some factors that effect quality are plant genetics, harvest practices, climate conditions, and agricultural management such as fertilization and irrigation. The absence of defects also contribute to quality as defects increase the product's susceptibility to damage and disease. Produce with defects are often rejected by consumers. 

Measurements and evaluation of appearance, texture, and taste can be conducted to ensure products are of high quality. Visual scales can be used for defects that show various examples compared to a farmer's products. Texture and taste can be evaluated through sensory analysis by having individuals taste the products and describe specific characteristics to develop profiles. 

Ana Silvia Colmenares, of Universidad del Valle Guatemala, is the presenter of this lesson.  

Curing roots, tubers and other underground storage organs

This 7-minute lesson on curing underground storage organs presents an overview of curing roots, tubers, and bulb crops. The curing process will vary based on the specific type of crop. 

Curing bulb crops such as onions or garlic entails drying the neck of the crop for up to five days, exposing it to warm and dry temperatures.

When curing bulb crops in the field, they can be left in the field exposed to the sun or put in stacks. Crops can be lightly covered to prevent sun burning and should be checked each day to monitor the drying of the neck. Bulb crops can also be cured in burlap sacks. This process may take longer as less airflow passes through, but can provide a uniform curing process. Curing of bulbs is important and beneficial as it extends the storage life of crops for several months.

Roots and tubers, such as potatoes, sweet potato, and yuca (or cassava), require moist, warm conditions allowing surface wounds to heal.

Curing of roots and tubers should remain warm and moist. These crops can be left in the field in small stacks, covered with cut grass and a canvas or jute tarpaulin. It is important that plastic coverings are not used for curing. Roots and tubers can take up to 10 days for sufficient curing. Relative humidity, depending on the crop, should stay between 85-100 percent. The curing process for roots and tubers also provides increased storage life, less water loss, and less decay to extend marketability. 

Lisa Kitinoja, of the Postharvest Education Foundation, is the presenter of this lesson.

Water sanitation and food safety for fresh produce

This 13-minute water sanitation and food safety lesson teaches the importance of food safety practices. Many fruits and vegetables are eaten fresh which can cause illness and disease if not carefully handled.

Contamination of fruits and vegetables can occur through the use of unclean water, contact with the ground or dust, or contact with farm animals. Contaminants that can cause illness include pathogens, most commonly from animals, or chemical residues from pesticides. Contamination can be prevented by applying the proper food safety practices. These include:

  • Water management
  • Personal hygiene
  • Cleaning and sanitizing materials
  • Prevention of contamination from animals
  • Proper use of animal fertilizer
  • Preventing contamination with chemicals

Alejandro Castillo, of Texas A&M University, is the presenter of this lesson.

Types of packaging for fruits and vegetables

This 10-minute postharvest packaging lesson reviews the importance of packaging to protect products during transportation and storage, which helps to maintain quality and extend marketability. Postharvest losses can be significantly reduced with the use of appropriate packaging.

The types of packaging materials selected for storage are important to maintain quality and prevent damage. Natural materials may be selected as they are low cost and readily available, but may not travel well over long distances. Natural materials can also be of lower quality and be less uniform in size or texture, which can cause damage to products. 

Some specific materials for packaging that are typically used include wood, paper, plastic or other natural or synthetic materials. Wood has been historically used for the construction of crates, but has recently been replaced by other materials due to their heavy weight and higher costs. Wooden crates are also difficult to clean well, making them harder to use multiple times. Wood packaging can have sharp edges that can damage produce. 

Natural and synthetic fiber bags or sacks are easy to make and low cost, but lack rigidity which can damage products due to a lack of protection and cannot be stacked on top of each other. Paper and plastic bags are often used by consumers to carry products from the market back to their homes. Other materials include cardboard boxes and plastic crates. 

Eleni Pliakoni, of Kansas State University, is the presenter of this lesson. 

Cooling and temperature management after harvest

This 9-minute lesson on cooling and temperature management explains that managing temperature is necessary to ensure quality of horticultural crops, from harvest to consumption. After harvest, fruits and vegetables are highly susceptible to water loss and changing conditions. Temperature management begins at the time of harvest. If temperatures are not properly managed, fruits and vegetables can significantly change their texture, weight, and nutrient content.

Reducing the time between postharvest processing stages can also help to maintain consistent temperatures. 

Some methods to manage temperature include the use of shade to prevent excessive exposure to high temperatures. This can be used on the farm after harvest, when produce is waiting to be transported. Shade can also be used at the market when produce is being sold to consumers.

Evaporative cooling systems can also be used to economically cool produce. Immersion by hydrocooling, or submerging products in cold or ice water, can help to manage temperature. This method can be used where access to cold groundwater or ice is easily accessible.

In all of these examples, once crops are cooled, they need to continue to be cooled. Maintaining the cool temperature will extend the quality and marketability of produce. Management of temperatures during postharvest is essential for ensuring products can make it to the market in conditions that meet consumer's preferences. 

Steve Sargent, of the University of Florida, is the presenter of this lesson.

Storage practices for fruits and vegetables

This 13-minute lesson on best storage practices promotes produce storage as an essential component of postharvest handling in horticulture. Fruit and vegetable storage is helpful to extend product marketability, avoid price drops, keep produce for processing, and reduce losses during long-term storage. While storage provides many benefits for farmers, several issues can arise that lead to reduced quality or increased losses. 

Certain types of fruits and vegetables may not be suitable for storage. Poor storage conditions and packaging can also reduce produce quality. Packages that are too full, stored in the wrong materials, or in a temperature that is not suitable to storage pose issues. Storage structures themselves that are not well designed or clearly organized will lead to poor results. 

Some viable options for storage that are simple designs include an underground root cellar, charcoal cool room, zero energy cool chamber (ZECC), and ventilated structures for bulbs or other crops that like dry conditions. Root cellars are underground storage chambers that are best suited for root, tuber, or winter crops. These structures are well insulated and should not receive significant sunlight or water moisture.

Charcoal cool rooms are good for crops that like high relative humidity. These are constructed of mesh walls filled with charcoal that remain moist allowing air to pass through keeping contents inside cool. A ZECC is evaporative cool storage made of bricks and sand. These can work well in certain climate conditions for short-term storage of leafy greens or vegetables like tomatoes or peppers. 

When storing any crop, it is important to conduct quality storage inspections. This includes making sure the structure is clean and without mechanical issues. Checking on produce quality can include recording the temperature of the storage chambers as well as dates when products were added and checked. 

Lisa Kitinoja, of the Postharvest Education Foundation, is the presenter of this lesson. 

Transportation of fresh horticultural crops

This 1-minute transportation of fruits and vegetables lesson provides a basic overview of the importance of transportation during postharvest. Transportation begins at the point of harvest when fruits and vegetables are picked and begin their journey to their next destination for further postharvest processing. It is important the delays in transporting horticultural crop after harvesting are reduced as much as possible. Delays between harvesting and transporting products provides opportunities for fruits and vegetables to be exposed to high temperatures which can impact their ripening and deterioration.

While it is important to prevent delays, it is also important to be careful when handling produce. Focusing solely on transporting products after harvest and between postharvest processes can impact quality if they are not handled properly. Minimizing the handling steps after harvesting also helps to maintain quality. Fruits and vegetables should be moved to a cool, shaded location for sorting and packaging and quickly prepared for transportation. During transportation, horticultural crops should be loaded and stored carefully to ensure they don't get jostled around or incur any damage. 

Jeffrey Brecht, of the University of Florida, is the presenter of this lesson.

Water loss during postharvest

This 7-minute postharvest water loss lesson introduces fundamental principles of water loss of horticultural crops and the impact on their quality. Once fresh fruits and vegetables are detached from their host plant, they are no longer able to take up water and begin to lose water through evaporation. Water makes up the majority of a fruit or vegetable's weight, so water loss will cause a reduction in the weight. This impacts the size, shape, and texture of produce. Subtle changes may include loss of sheen whereas significant changes will include shriveling. 

Water loss of fresh fruits and vegetables can also lead to significant changes in nutritional value and flavor content. Leafy vegetables such as lettuce will lose water much more rapidly than bulky fruits such as tomatoes or melons, as they have a significantly higher surface area where water evaporation can occur. Regardless of the size of the horticultural crop, the surface is the main barrier preventing significant water loss. Any time damage occurs to the surface of fruits and vegetables, water loss can be accelerated. 

The environment in which crops are stored can have significant impacts on the water loss of a product. The more humid a surrounding environment is, the lower the water loss will be. Dry or desert-like environments will exhibit more water loss. Higher temperatures will also accelerate water loss. This is why keeping fruits and vegetables in shaded and cool environments is essential to postharvest handling. 

Mark Ritenour, of the University of Florida, is the presenter of this lesson.


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