Postharvest handling involves moving a perishable product from point A to point B with the least amount of harm to quality and shelf life. Perishable is the key word. If produce were hardware, there would be fewer concerns about temperature, humidity, bruising, ethylene, or shelf life. However, fresh produce is living tissue and this must be acknowledged and respected to protect quality.
Most consumers are unaware of the many complicated steps required for moving produce from the grower to the consumer and assuring that the produce arrives in freshly picked condition. In modern commerce, growers are increasingly separated from the consumer by time and distance. Making this system work requires many sophisticated technologies. Keeping produce properly cooled is not all that is required. Temperature management is important, but there are many other postharvest actions that are essential in the delivery of safe, fresh produce to the consumer.
Most growers of fresh produce learn that preparing produce for market (washing, grading, and packaging) is as important to the overall success of the enterprise as anything that happens in the field. Care that is exercised in the packing house is rewarded with good prices and repeat business. No matter how good a crop is at harvest, lack of care after harvest will have negative consequences for the business.
Harvesting
Pre-harvest and harvesting activities and conditions related to crop production can and often do have a profound influence on the quality of produce delivered to the consumer. Crops stressed by droughts, floods, insects or disease damage, herbicide injury, and improper variety selection can have a significantly shortened shelf life. With some crops, an excessive amount of nitrogen fertilizer applied before harvest or moist, warm conditions before or during harvest may increase the chances of postharvest rots. In many cases, the damage to the product that occurs in the field is not evident immediately. For example, root crops growing in flooded fields may not show signs of breakdown for several weeks or more after picking. Thus, produce that appears acceptable when harvested may be totally unacceptable by the time it reaches the consumer. The consumer is the final and most important judge of quality. A grower’s bad reputation for frequently delivering a poor quality product to the buyer is very difficult to overcome.
All produce is composed of living, respiring tissue. The physical actions associated with harvesting and handling are the most stressful the produce will experience. Harvesting involves separation from the parent plant that leaves an open wound along with other wounds from trimming and mechanical damage. The act of gathering the produce into bins, hampers, or trailers often causes bruising and skinning that results in additional open wounds. The bouncing and jarring during transport can also cause damage. Each of these wounds damage tissue that becomes a potential site for postharvest rots. In addition, harvesting often takes place in hot, wet, and dirty conditions, which are precisely the conditions that stress the producer most. In addition, many postharvest rots are soil born and thrive in warm, wet, and dirty environments.
In addition to stress on the produce, a warm, wet, and dirty environment also stresses the harvest worker. Harvesting is physically demanding, and requires stooping, squatting, and lifting heavy loads. Few people choose this work if work that is less demanding is available. Consequently, mechanization of agriculture, especially harvesting, has been a goal since antiquity.
At the beginning of the industrial revolution, one of the early successes in harvest mechanization occurred with grain crops. Machines (combines) that combined the functions of cutting and threshing grain into one operation were developed. Over the years and especially during periods of labor shortages, agricultural mechanization of all types of crops attracted the attention of inventors. In recent times, there are those who envisioned that all agricultural operations for all crops, including harvesting, would eventually be computerized and mechanized. However, despite considerable efforts, the reality is that much fresh produce is still harvested by human hands. A few produce crops that are grown in large amounts, such as potatoes and onions, have had their harvesting effectively mechanized. It is difficult to know if the large acreages forced mechanization or mechanization allowed for the large acreages. Considerable work has been done to mechanize fresh produce harvesting and handling, but much more remains to be done.
For a crop to be effectively mechanized, it must be grown in sufficient volume to make the investment in mechanization economically viable. Grain crops such as corn, wheat, and soybeans are grown on millions of acres, which makes the investment in mechanization research and development and the growers’ investment in machinery worthwhile. The fact that expensive grain combines, for example, can be used with multiple crops has had a positive influence on their wide-scale adoption.
With a few notable exceptions, many produce crops are limited in the acreage grown by individual growers. Given the varied nature of horticultural crops, a mechanical cucumber harvester, for example, cannot be easily used with other crops. A mechanical tomato harvester can be used only with a certain segment of the tomato crop such as processing tomatoes. Tomato varieties intended for processing into juice, sauces, or paste are developed specifically for mechanical harvesting and are handled much like a commodity in the same way as corn or small grains. However, these machines cannot successfully harvest high value table tomatoes that bruise more easily.
Many produce crops must be harvested multiple times because individual items mature at different rates and require discrimination in quality, size, shape, or color. A mechanical harvester that picks everything will gather overripe, under ripe, or diseased produce that must then be separated at a later stage of processing. These are “once-over-and-done” machines that generally destroy the crop during harvest so that it cannot be used for crops that mature over an extended period. There is ongoing research with machines that can find fruits or vegetables in the plant canopy, discriminate, and then determine if it is ready to harvest. This is a promising line of research.
Machines are expensive, complicated, and require skilled, expensive labor to service and operate. Mechanization is the exchange of capital for labor. The goal is to replace hand labor with machine labor with the same level of care for quality. There are examples when this has been successful, although some growers have purchased very expensive machines that damaged the produce to an unacceptable level or required just as many hands to undo what the machine has failed to do. Some growers question the wisdom of purchasing and operating an expensive, high maintenance machine when they need nearly the same number of workers working manually to make the machine’s operation successful. For the past 50 years, we have had the benefit of relatively inexpensive manual labor, which has dampened or even eliminated much of the incentive to produce mechanization for harvesting.
An additional reason for the failure to mechanize produce crops is the conscious or unconscious attempts to “anthropomorphize” the machines. Since harvesting produce often involves grueling stoop labor, it is natural for machine designers to work toward eliminating much of this labor. Potential machine designers often envision a machine that copies the motions and functions of a human. The successful harvest of a fruit or vegetable by a human requires skill, dexterity, judgment, and excellent hand-to-eye coordination. Machines are efficient at lifting heavy loads quickly, but despite computers, sensors, and machine vision, most machines have difficulty duplicating the basic skills of a worker.
Some mechanical produce harvesters have proven successful when there is considerable plant, fruit, or vegetable uniformity (size, shape, color) or when the machines have performed the harvest functions in ways that are unique to the machines. For example, multiple rows of carrots can be pulled rapidly from the ground, trimmed, and loaded into wagons by a machine that only requires a driver. Similar machines are used for snap and lima beans.
Many successful efforts to mechanize produce harvesting have occurred when designers and engineers recognize the advantages and limitations of the human and the machine. These machine-human hybrids are called harvesting aids. Most seek to reduce the drudgery by allowing the workers to work in a more comfortable position. Figure 8-2 is an example of a harvesting aid developed at North Carolina State University for picking strawberries. Harvesting aids like this one generally divide harvesting into discrete functions that allow for economy of movement by the workers. By doing this, harvesting aids can significantly enhance worker productivity, although the success is constrained by the limitations of humans and the cost of the machine.
Another excellent example of the widespread use of harvesting aids is the “mule trains” that are used to harvest crops such as lettuce, cabbage, celery, broccoli, and melons. Given the uniformity of the crop in the field, the harvesting and packing operation involves a moving platform that integrates most but not all the harvesting and packing functions. Figure 8-3 is an example of a mule train used in California for harvesting lettuce. Although the crop is very uniform, some grading and trimming is required by the crew riding on the machine. The end product is boxed and palletized lettuce ready for cooling and shipment.
Figure 8-1. Machine harvesting sauce tomatoes in California with a “once over machine.”
Source: UC Davis Department of Plant Sciences.
Figure 8-2. Harvesting aid used to pick strawberries.
Source: M. Boyette.
Figure 8-3. Mule train harvesting and field packing lettuce in California.
Source: M. Boyette.
Mechanical Damage
Fresh produce is delicate and susceptible to damage, whether harvested by humans or machines. Care must be used at all times when handling fresh produce to reduce mechanical damage. Quality must never be sacrificed for speed. Whether by machine or human hands, speed invariably imparts energy as the produce goes from plant to harvest container or from transitions in the packing house. Abrupt stops or starts can damage produce in two ways. When a produce suffers a direct impact, a bruise will occur that is not always visible initially. Even if the bruise does not break the skin, the force of the impact can rupture and kill layers of cells immediately under and around the impact area. Skinning is a second way that produce can be damaged mechanically. Skinning occurs when an item slips past another item or a surface with enough force to break the skin and expose raw cells. Wounds that break the skin are more likely than bruises to create sites that can become postharvest rots.
In general, if you can hear the produce items hitting each other on the harvester surfaces or as they move through the packing line, the produce is probably being damaged. Symptoms of injuries (rots and dark spots) may not be evident until much later. By that time, the produce has reached the consumer and it is far too late to preserve the quality. Most fresh produce is purchased on impulse. Appearance is important. Bruises and other mechanical damage cannot be reversed and detract from the appearance of the produce. The key to reducing damage is very simple: handle all produce carefully.
Here are some recommendations that can help reduce damage during harvesting:
- Emphasize to the laborers that the produce must be handled gently. Ask all workers to avoid throwing or dropping the produce into picking containers or bins. For some types of very delicate produce, such as berries, it is necessary for workers to keep their finger nails trimmed or to wear cotton gloves to avoid cutting and scraping to the fruit.
- Harvest the produce at the proper stage of maturity. Harvesting too early can result in poor color or taste, while harvesting too late can result in increased decay and a much shorter shelf life.
- If possible, harvest the produce only when it is dry. Avoid harvesting after a rain or heavy dew when the produce is wet and may be covered by soil particles. These particles can scratch the produce and may contain millions of decay organisms that are easily spread.
- Handle produce as little as necessary. In some situations where there is uniformity is size and quality, it is possible to pack the produce in the field without a dedicated quality assurance function other than the judgment of the harvesters. This can reduce handling and the resulting damage, as well reducing the time from harvest to cooling and shipping. Anything that can shorten the chain from field to consumer will reduce cost and preserve quality.
- Do not overfill bulk bins or picking containers, especially if they are to be stacked. Stacking overfilled containers can result in the bruising of virtually every item in the container. For some very delicate items, it may be necessary to line the bottom of picking containers and the side and bottoms of bulk bins with padding to prevent injury. In the past, pieces of carpet have been used to reduce damage, but this is discouraged because carpet is very difficult to keep clean and may harbor pathogens and decay organisms. Washable foam, made especially as produce padding, is now available and is the better choice.
Packing Lines
Packing lines vary widely and with the exception of the simplest are almost always custom designed to fit the specific needs of the product and the packer. Two packing lines that pack the very same product can vary significantly. In general, packing lines share a number of similar characteristics in form and function as shown in Figure 8-4.
- Clean produce of soil, debris, and other foreign matter.
Most produce grows in the ground, on the ground, or near the ground. Despite our best efforts to keep dirt in the field, soil, plant debris, and foreign matter are often mixed together with the produce. Upon reaching the packing facility, the first action should always be removing all foreign materials. The reason is simple. When these materials are allowed to pass along the packing line, time and effort will be spent on handling material with no market. In addition, foreign materials are often the source of rots and food pathogens. Eliminating all foreign materials at the beginning reduces the likelihood of contaminating the entire packing line.
Washing produce with water is common in produce handling. This might involve water sprays as the produce moves along a belt, a brush conveyor, a roller table, or a large water tank (dump tank) that also acts as a surge bin. A surge bin is a packing line capacitor that allows the produce to be unloaded from field containers in large units and fed into the packing line in a continuous smaller stream. Dumping produce into a water tank from a harvest bin can cause significant bruising if done rapidly. Research conducted some years ago found that more mechanical damage occurs at this point than at any other part of the packing line.
In the dump tank, the debris that floats to the surface may be skimmed off, while the dirt either settles to the bottom or floats in suspension. This requires flushing and refilling the dump tank periodically, which can use a significant amount of water. Dump tanks can be flushed manually by opening the large slide valve for a few seconds on the bottom or by installing a level sensor that would activate the slide valve that responds to a rising water level. This automated flushing arrangement may be used if there is a rinse step after the produce is removed from the dump tank. In this case, this rinse water can be collected and used to refill the dump tank, which saves water.
Some packing operations have attempted to reduce the potential pathogen load by dosing the dump tank water with chlorine in the form of calcium hypochlorite, the material used to chlorinate swimming pools. This is generally not a good approach. First, at the recommended rates, dirt and the other contaminants in the water absorb most of the free chlorine, which leaves limited chlorine available to act on the pathogens. Second, using the recommended rate above is illegal and often makes working around the dump tank very unpleasant. The chlorine corrodes metal and may also be an industrial waste violation after disposal. Third, the effectiveness of the chlorine is influenced greatly by the temperature and pH of the water. This must be monitored closely. The use of postharvest chemicals is governed by state and federal laws. For more information, consult the North Carolina Agricultural Chemicals Manual.
With root crops that come from the field with a great deal of soil, disposal of the mud and muddy water are waste management issues that require dedicated settling ponds and other waste mitigation measures (see Figure 8-5). The proper disposal of packing house waste, both liquid and solid, when handled in a responsible manner such as composting or a land application, may or may not be exempt from most industrial waste regulations. For more information on the disposal of agricultural waste, contact the North Carolina Department of Environmental Quality, Division of Waste Management.
- Remove diseased, damaged, and below acceptable quality produce.
Despite the best efforts of human or machine harvesters, all produce that arrives at the packing house will not be marketable. Items with decay not evident in the field, cuts, bruises, skinning, or odd shapes and sizes should be eliminated as early in the packing process as possible. Although computers, machine vision, and even artificial intelligence are making progress in this area, this sorting process requires skill and judgment and is still done primarily with human eyes and hands.
From the washer, the wet produce is distributed evenly on a roller table, which is a specialized conveyor with rollers that rotate the produce under fans and good lighting past human workers who remove the substandard material. This portion of the packing line is called the “eliminator” or “pick out table” (see Figure 8-6). The discarded produce may be composted, fed to animals, or processed into value-added products. For example, the entire baby carrot industry was based originally on processing broken, undersize carrots that were not suitable for the usual size bagged carrots.
After workers remove the produce that cannot be sold, the remaining produce moves to the sizer. Depending on the type of produce, there can be an intermediate step between the eliminator and sizer when postharvest chemicals such as fungicides are applied by spraying or dipping. At this point, items such as apples or cucumbers may have a food grade wax applied to preserve freshness and enhance visual appeal.
- Segregate the produce according to shape, size, and color.
Produce is a natural product that can vary in many ways. A major function of grading is to ensure uniformity in the pack. Buyers are often most concerned about all items in a carton being the same. The impulse to purchase a particular produce item is based on appearance. Sorting by size, shape, or color adds order, visual appeal, and value to otherwise mixed lots of produce. For example, uniformity is very desirable for produce that will be used in restaurants where the portion size may be based on the individual item such as baked potatoes, which must all be the same size. Bulk displays of produce in grocery stores encourage sales and allow the shopper to select individual items. When all items are alike, there will be very few items that are left unsold and must be discarded at a loss. Even produce sold to processors (fresh cut, canning, or freezing) should be uniform to aid in efficiency and reduction of waste in processing.
When sorting fresh produce, a characteristic such as size, shape, weight, or color is measured and used to segregate items into similar lots or classes. The engineering of mechanical sorters ranges from very simple to extremely complex. For example, a fresh tomato sorter may employ a series of belts with different size holes through which the tomatoes can or cannot pass. This sorts the tomatoes by size. In the fruit tree industry, sorting is often done by weight. Each individual produce item is moved into a cup on a conveyor belt under which there is a weigh scale. As the produce passes down the conveyor, items of a similar size are off loaded (see Figure 8-7).
Another type of sorter has a conveyor with plastic tubes. As the bars pass down the conveyor, they become progressively further apart, which allows the smallest produce to fall through first before the larger and larger items. Extra-large items may be carried completely to the end of the conveyor and collected there. These sorters select for diameter but not length, and work well for items such as potatoes, carrots, and cucumbers where the length is proportional to the diameter (see Figure 8-8). With items that vary in length as well as size like sweetpotatoes, these sorters may not provide the level of sorting demanded by the market. These sorting machines are simple, rugged, have a relatively high throughput, and have proven themselves for many years.
In the last several decades, produce sorting has benefited greatly from advances in computer and sensor technology. For example, tomatoes harvested by a “once over” machine will collect fruit in various stages of ripeness. Where these were once color sorted by humans (see Figure 8-9), the sorting process is now largely done by computerized color sensors that are much faster and more accurate.
There are also sensors that detect defects in produce. Engineers have been working on new sensing technology for detecting internal defects in fruit and vegetables by using lasers and light scatter. The demand for more precisely graded packs and better quality produce has increased and has encouraged the application of machine vision on the packing line. These machines are fast and accurate. Some larger machines can scan at rates close to 100,000 individual items per hour.
From a pair of two dimensional scans, the software produces a computer scan that can be measured precisely for size, shape, curvature, color, surface area, and weight, as well as internal and external defects. This technology has two benefits. It produces a very precise pack of great uniformity, and some critical data. With sophisticated statistical methods, this information can be compared to the cultural data of the same lot (yield, variety, plant and harvest date, rainfall, fertilizer, and soil type) to provide important new insights into agricultural techniques.
General Produce Handling
Washing, grading, and packing are all necessary for delivering the best quality produce to the consumer. Even with direct sales to consumers, some form of grading and handling is often necessary. For producers who plan to sell to wholesale buyers, restaurants, and grocery stores, proper washing, grading, and packing is essential. However, the reality is that much that is done to fresh produce is the direct opposite of proper handling. The produce is often dumped into dirty water that contains billions of active disease organisms. Produce is scraped, skinned, and bruised as it passes through various parts of the line. When still wet, produce falls, often a yard or more, into a warm dark box and remains there for some time while awaiting shipment. A better situation could hardly be devised for the spread of disease. Even with very gentle handling and various chemical treatments, post-ship decay occasionally ruins entire shipments of produce before they reach the consumer. Having a shipment of produce rejected by a buyer because of decay is one of the most costly situations a packer or shipper can encounter because the entire cost of production is lost.
The mechanical damage to produce during handling may take the form of cuts, abrasions, and bruises. Recent research has suggested that strategies to reduce mechanical damage during handling must consider the nature of the product to be completely successful. For example, apples, peaches, tomatoes, and onions are easily bruised, but are less susceptible to abrasion or skinning. On the other hand, potatoes, sweetpotatoes, and squash may be more susceptible to skinning than bruising. These findings suggest that no single strategy can be used on all produce and all lines. Injury sites may be immediately apparent or may not emerge for several weeks. Damage is not limited to breaking the skin. When the skin is broken, however, the break is an ideal site for rot organisms.
Although some older packing lines are very harmful to produce, much can be done to reduce mechanical damage during handling. Many newer lines have been designed to minimize damage. Unfortunately, small-scale producers often find it difficult to justify the purchase of new equipment and may have a limited selection of good used equipment available to them. Some producers may be forced to assemble and install their own improved line from parts obtained from several sources. If this is the case, here are some practical recommendations:
Recommendations for reducing handling damage on a packing line
- When appropriate, gently unload the produce into a tank of water from the harvesting containers. Some produce items cannot tolerate wetting. For those that do, unloading into water will reduce scrapes and bruises substantially and will aid in cleaning.
- Keep packing lines as level as practical. Packing lines that continually raise and lower the produce generate potential energy that results in mechanical damage. For example, when produce is elevated by a belted conveyor or other means, potential energy is imparted that is proportional to the height raised. When the produce is allowed to fall or roll back to the lower level, the potential energy is changed into kinetic energy (motion), which must be absorbed by the fruit or some surface. This will result in damage. In addition, conveyors should be operated close to full capacity but slowly as possible because this reduces damaging collisions. Operating a packing line far below full capacity provides the produce with less restraint on velocity, which consequently causes more damage.
- Minimize drop heights. When it is necessary to lower produce from one level to another, as with box fillers, it should be done as gently as possible by the generous use of energy absorbing padded surfaces. Long inclined surfaces are better for reducing produce velocity than near vertical falls. Produce conveyor belts have minimal energy absorbing ability. When produce is allowed to drop onto a belt supported by sheet metal or rollers, the level of bruising is nearly the same as if the belt were not there. If possible, the supports should be removed to allow the belt to be suspended, which provides an energy absorbing impact surface. Decelerator strips of plastic also may be installed over inclines to control the rolling velocity of the produce.
- A good quality cushioning material should be used on all impact surfaces. The ideal material should be thick and moderately soft with a tough surface that resists wear and prevents the absorption of water and dirt. Padding material should be easily cleaned during a periodic wash down. Odd carpet remnants should never be used for padding because they are not very durable, are difficult to clean, and may allow pieces to break off into the pack.
- Packing and grading line components should be well synchronized to prevent damaging abrupt changes in velocity or the direction of the produce. Cross conveyors should be carefully engineered to allow a gradual change in direction and velocity by the use of curved and padded transitions. Packing lines should be operated no more quickly than necessary to reduce produce damage and wear-and-tear on the components.
Recommendations for a worker-friendly packing line
Packing lines should not only be produce friendlyꟷthey should also be worker friendly. Most packing lines rely on hand labor to sort the produce. To hire and retain good employees, it makes good sense to make the packing line safe and worker friendly.
- Keep sorting tables at a comfortable height. A height of 36 to 40 in. is a comfortable height for standing workers.
- Sorting tables should also be narrow enough to eliminate excessive reaching. Culls that cannot be reached easily will be allowed to pass by.
- Continuous stooping, bending, or odd working positions contribute to worker fatigue, as well as safety and morale problems. Worker comfort has a large influence on productivity.
- Workers cannot remove what they cannot see. The type of lighting over a sorting table and its intensity are very important to efficient defect removal. Select daylight spectrum lights that give the produce a bright natural color and are not tiring to the eyes. Any glass lights must be shielded against breakage since broken glass in the pack is a serious consumer safety hazard.
- Try to maintain the flow of produce along the line as constant as possible. Workers prefer to be comfortably busy, which means neither waiting for the produce nor being overwhelmed.
- Use splash guards to keep the workers standing near the washers dry. Keep the floors as dry as possible.
- Finally, when considering the design and layout of a packing line, remember the first law of industrial engineering: “Always make it easy for the worker to do the right thing.”
Sanitation
It is practically impossible to avoid injuring produce during handling. Decay producing organisms, especially those that cause soft rot (Rhizopus sp.) enter produce through injuries. Bruised or crushed tissue is a favorable place for decay to develop. To reduce the potential spread of disease, growers may treat some fresh produce with chlorination or other approved fungicides.
Chlorination is one of several chemical options that are available for managing postharvest diseases. When used with other proper postharvest handling practices, chlorination is effective and relatively inexpensive. Chlorination, when used correctly, poses little threat to health or the environment.
Chlorination is applied either by dipping the produce into a tank of solution or lightly spraying as the produce passes along a conveyor. Either method is effective with complete coverage, although no treatment will be 100% effective. Even with proper treatment, there may be significant decay. For specific recommendations on the use of postharvest fungicides or any agricultural chemical, refer to label instructions and the latest edition of the North Carolina Agricultural Chemicals Manual.
Good sanitation makes good sense. No matter how careful the operation, decay producing organisms that are brought into the packing house with the produce will quickly contaminate all working surfaces. The organisms remain viable for many months on surfaces such as picking containers, tank walls, sorting belts, rollers, and brushes. All floors and equipment that handle produce should be washed daily to remove dirt and any decayed produce. Disinfect the equipment on a regular basis with a strong chlorine solution which is nine parts water to one part household chlorine bleach. Keep the packing area and the immediate area clear of any decaying produce that might be a ready source of contamination, and clean the floor drains to prevent blockage.
Food safety is a serious matter. Fresh produce is often eaten raw and sometimes unwashed. Contamination can have serious consequences. Handlers are responsible for ensuring that all surfaces that touch the produce are thoroughly clean. Cleanliness is important for preventing bacterial and chemical contamination, as well as odor transfer. Any opportunity for contact with chemical residues from fertilizers, pesticides, and other chemicals must be eliminated. There is no more certain way to ruin your business than to be the source of an outbreak of food contamination.
Figure 8-4. Simple packing line layout.
Source: M. Boyette.
Figure 8-5. This large settling pond adjacent to a sweetpotato packing facility is 30 ft wide by 150 ft long by 8 ft deep and requires emptying three to four times per year.
Source: M. Boyette.
Figure 8-6. An eliminator in a sweetpotato packing facility where any defective produce is removed. The produce remaining on the eliminator is judged as salable.
Source: M. Boyette.
Figure 8-7. A produce weight sorter being used for apples. The weight cups are shown on the top of the conveyor. At an appropriate point, apples of similar weight are off-loaded.
Source: M. Boyette.
Figure 8-8. Variable bar width sizer.
Source: M. Boyette.
Figure 8-9. Color sorting tomatoes by hand.
Source: M. Boyette.
Publication date: May 1, 2025
Other Publications in Introduction to the Postharvest Engineering for Fresh Fruits and Vegetables: A Practical Guide for Growers, Packers, Shippers, and Sellers
- Chapter 1. Introduction
- Chapter 2. Produce Cooling Basics
- Chapter 3a. Forced-Air Cooling
- Chapter 3b. Hydrocooling
- Chapter 3c. Cooling with Ice
- Chapter 3d. Vacuum Cooling
- Chapter 3e. Room Cooling
- Chapter 4. Review of Refrigeration
- Chapter 5. Refrigeration Load
- Chapter 6. Fans and Ventilation
- Chapter 7. The Postharvest Building
- Chapter 8. Harvesting and Handling Fresh Produce
- Chapter 9. Produce Packaging
- Chapter 10. Food Safety and Quality Standards in Postharvest
- Chapter 11. Food Safety
- Postscript — Data Collection and Analysis
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