Sustainable Postharvest Handling

Sustainable Postharvest Handling

The world is abuzz with talk of climate change, greenhouse gas emissions, agricultural sustainability, and carbon footprints. At the same time, there is concern about long-term petroleum reserves. Our food system is an important user of fossil fuels and producer of greenhouse gases. Buyers are asking their food suppliers for their carbon footprint along with information about how sustainable their farming practices are. New legislation has been proposed, and in California a new law (AB32) requires a 20% reduction in greenhouse gas emissions across all sectors by 2020 and 80% by 2050.

Recent studies indicate that our food system consumes close to 16% of the total energy use in the U.S., yet only 2% of the total energy is used to grow the food we eat. Since fossil fuels are the predominant energy source, this results in significant greenhouse gas emissions and a large carbon footprint for the food industry. However, the carbon footprint is not the same for all types of food. It varies depending on how they are produced, processed, packaged, and transported.

For example, organic production uses less energy in the form of nitrogen fertilizer than conventional production, but hauling organic chicken manure more than 20 miles can eliminate the advantage. Tomato sauce requires energy to process but it weighs less and requires less energy to ship than the equivalent amount of tomatoes required to make the same amount of spaghetti sauce.

A detailed and systematic analysis of the differences in energy use and greenhouse gas emissions of individual foods is required to allow producers, buyers, and consumers to make informed choices. A life cycle analysis approach is needed to develop a complete understanding of the greenhouse gas emissions of various foods.

Is it more or less sustainable to ship freshly harvested produce items across the globe rather than producing them locally and storing for off-season supply? This depends on the produce item and how it is handled after harvest, and the answer is not always obvious. Products shipped by sea may have a much smaller carbon footprint on a per pound-mile basis than products transported by truck or passenger car in much shorter distances. To enjoy apples produced locally for nearly 12 months of the year, the apples must be kept in refrigerated storage in an atmosphere of low oxygen and elevated carbon dioxide. Marketing these fruit throughout the U.S. involves truck transit to markets that may be thousands of miles away.

Is it more sustainable to buy only produce items produced within 100 miles of home? The distance you must travel by car to purchase these products is critical in the analysis because of the small amount of product transported by automobiles. Compare a refrigerated truck hauling 40,000 pounds of apples with a 6 mile-per-gallon (mpg) efficiency with a car hauling 2 pounds of apples with 20 mpg efficiency. Food miles and carbon footprint must be calculated on a per unit of food basis.

Less Waste, Post Haste

Postharvest technology can make a significant contribution to reducing the carbon footprint of food systems. Energy for cooling can be reduced by using efficient cooling operations and managing them well. In addition, harvesting products during the cooler parts of the day and avoiding exposure to the sun after harvest through the use of shade materials will reduce the heat load that must be removed from the product. Maintaining the cold chain once the product has been thoroughly cooled will prevent the need for re-cooling and reduce energy use. 

Reducing wasted food is something everybody can do to reduce the greenhouse gas emissions in our food system. Depending on the commodity, postharvest losses range from 5% to 25% in developed countries and 20% to 50% in developing countries. A recent survey carried out in the UK claims that an estimated 4.4 million apples are tossed every day along with 5.5 million potatoes, 2.8 million tomatoes, 1.6 million bananas, and 1.2 million oranges due to deterioration problems. Based on these estimates, these five items alone add up to 525,000 tons of food waste a year (according to

The USDA Economic Research Service estimates that in 2005, 57% of fresh fruits and 51% of fresh vegetables, by weight, were not consumed. According to a recent article in the Hindustan Times, up to 30% of food produced in India is wasted because of poor postharvest handling.

Given the electricity, fuel, fertilizer, and water invested in producing a crop, to have 57% of it never consumed is a tremendous waste of resources that greatly increases the carbon footprint of the food industry. The industry has invested in harvest aids, packing equipment, packaging, cooling facilities, storage technologies, and air-ride suspended truck trailers that help maintain the quality of fresh fruits and vegetables, allowing them to make it to market in good condition for purchase and consumption. However, there is still room for considerable improvement, and we should invest at least as much energy and resources into improving postharvest handling as in improving our production practices.

Leave a Reply

Featured Stories

All Vegetables Stories >All Fruits Stories >All Nuts Stories >All Citrus Stories >

The Latest

TomatoesProduction Reaches An All-Time High For Processing Toma…
August 29, 2014
A record high is predicted for the 2014 processing tomato crop. Read More
CitrusFlorida Department Of Citrus Knocks NPR Piece Over Juic…
August 28, 2014
Agency goes to bat for the industry regarding statement slighting OJ's health benefits. Read More
Disease ControlLate Blight Update Reveals Heightened Activity
August 28, 2014
While several states in the Northeast have confirmed the presence of late blight, the disease has not been reported in North Dakota or Minnesota. Read More
CitrusFlorida Energy Firm Charged Up About Citrus Biomass Pot…
August 28, 2014
Machine called a game-changer when it comes to a cost-effective, efficient way for tree removal and re-purposing. Read More
EquipmentNew Tractors Improve Maneuverability And Operator Contr…
August 28, 2014
The Magnum Rowtrac tractors from Case IH meet growers’ cropping needs through a wide variety of row spacing and belt options.   Read More
NutsCalifornia County Passes Ordinance To Protect Walnut Gr…
August 27, 2014
Verification of ownership needed to complete sales of valuable nuts. Read More
NutsAlmond Growers Hit By Russian Import Limits
August 27, 2014
Growers reflect on changes to export market in light of produce ban. Read More
Farm ManagementLeadership And Management Expert To Speak At California…
August 27, 2014
Daniel Goleman will make presentation at California State University-Fresno. Read More
CitrusNational Scientific Summit On Herbicide Resistant Weeds…
August 27, 2014
Topics to be covered include the economics of proactively managing herbicide resistance, education and outreach efforts, and incentives and regulatory initiatives. Read More
FruitsFlorida Organic Group Dedicated To Serving Growers, Com…
August 27, 2014
Education and development programs are plentiful for interested producers. Read More
VegetablesExperimental Herbicide Technology Blasts Weeds In Rows
August 27, 2014
The technology uses an air compressor to spray corncob grit on both sides of a crop, killing young weeds. Read More
Disease ControlFungal Disease Outbreak Hits Pacific Northwest Vegetabl…
August 27, 2014
An outbreak of blackleg, light leaf spot, and white leaf spot can be significant problems in several vegetable crops.   Read More
CitrusClean Water Conundrum: Ditch The Rule Or Ditch The Myth…
August 26, 2014
Regulation inundation causing a rising tide of confusion for farmers. Read More
BerriesMichigan State University Extension Offers Tips To Prev…
August 26, 2014
Humidity, rainy periods conducive to disease development. Read More
FruitsSpotted Wing Drosophila Populations Rising In Michigan
August 26, 2014
Extension researchers advise berry growers on trapping, salt testing to take stock of pest population. Read More
Apples & PearsNorthwest Pear Crop Estimate Revised Upward
August 26, 2014
Washington and Oregon pear growers forecast a larger size crop than that originally estimated. Read More
VegetablesAgrium Acquires A Controlling Interest In Biotech Compa…
August 26, 2014
The company also acquires stake in Agricen Sciences as part of strategic effort to expand their offering of integrated, next-generation plant health technologies. Read More
Insect ControlCover All Angles When Taking On Threecornered Alfalfa H…
August 25, 2014
Learn how to ID, the survival and spread, and management methods for this insect pest. Read More