Pushing Perishability

Pushing Perishability

Sweet corn continues to be a valuable fresh-market crop for Florida growers. During the 2008-2009 season, Florida extended its reign as the No. 1-producing state, with a value exceeding $227 million harvested from 43,100 acres. Sweet corn is the second-ranked vegetable in the state, behind tomato, with an average season price of $16.28 per 42-pound crate. Supersweet varieties continue to dominate the fresh market and, although they remain sweet longer than traditional varieties after harvest, proper postharvest management is still critical to assure market quality and acceptability. There are principles and practices for keeping sweet corn quality fresh.

Quality And Perishability

High-quality corn is tender and sweet, and that begins with proper harvest maturity. Kernel juice should be milky for sugary (su1) and sugary enhanced (se) varieties, whereas shrunken 2 (sh2) varieties have watery juice. Ears should be picked when the tip kernels are filled but not oversized. Husks should be green and fresh in appearance with dried silks. Trimming flag leaves and shanks reduces moisture loss during handling and shipping; completely husked ears lose much less moisture than those with husks.
 
Sweet corn is one of the most perishable vegetables. Its high respiration and tendency to lose water mean that, if not cooled promptly and thoroughly after harvest, stored reserves in the kernel will be quickly consumed. This leads to loss of sweetness, shriveling (denting), tougher kernel texture, and dried husks. Corn that is cooled to near 32°F (0°C) within an hour or so of harvest can be expected to remain in good condition at that temperature for more than 14 days. However, failure to cool the ears properly shortens the postharvest life. For example, cooling to only 50°F (10°C) would shorten postharvest life by a factor of 4, or to less than four days.

Cooling Methods

Three methods effectively remove field heat. Hydrocooling is widely used because it can be applied to bulk corn in bins, to individual packages (returnable plastic containers-RPC’s; waxed cartons; wooden wirebound crates) and to pallets. Slush-ice cooling is a form of package icing, in which a slurry of finely crushed ice in water is injected into or on top of the packed corn container. Both hydrocooling and slush-ice cooling hydrate the corn. Vacuum cooling also is used to cool corn at high-volume operations; however, the corn must be wetted prior to cooling in order to minimize water loss.
 
Several factors decrease cooling efficiency, thus extending cooling time. The more the corn is packaged, the longer the cooling time because the package restricts contact between the cooling medium and the product. For example, crated corn requires 25% more cooling time than bulk-packed corn. Undersized cooling equipment is another common cause of delayed cooling, since the system does not have sufficient cooling capacity to maintain the setpoint water temperature.

Trimmed And Fresh-Cut

With increasing consumer demand for convenient, ready-to-eat vegetables, various types of husked and trimmed sweet corn, and even fresh-cut kernels, have been developed and marketed. These products are more perishable than traditional bulk sweet corn and, in order to remain fresh and appealing, they require special packaging to supplement temperature control and manage water loss and elevated respiration. If cut kernels are not handled exclusively at near 32°F or at slightly higher temperatures in modified atmosphere packaging, they can turn brown when cooked. Kernels removed intact from cobs don’t discolor when cooked, and they also maintain higher sugar content and better flavor than cut kernels.
 
Now is a good time to check over existing cooling systems prior to the start of the spring harvest season. Always work with a reputable refrigeration contractor with experience in fresh produce.

Leave a Reply

4 comments on “Pushing Perishability

  1. Foil bubble insulated products from IPC. Our bubble and foil wrap products are designed for temperature and cool packaging applications. thermal pallet cover

  2. Foil bubble insulated products from IPC. Our bubble and foil wrap products are designed for temperature and cool packaging applications. thermal pallet cover

Featured Stories
California's "Citrus Belt" is on the east side of San Joaquin Valley, not far from the Sierra Nevada foothills. (Photo credit: David Eddy)
Citrus
May 3, 2016
New Program Targets Abandoned California Citrus Trees
Bayer and California Citrus Mutual have teamed up to help protect the state’s commercial citrus industry from deadly citrus greening. Read More
Extreme close-up of redbay ambrosia beetle
Fruits
May 3, 2016
How To Build A Better Beetle Trap
UF/IFAS study on luring, snaring the notorious redbay ambrosia beetle earns prestigious award. Read More
Shockwave, a long shelf-life cantaloupe with higher sugar content than most varieties is available from Holmes Seed Co. and Harris Seeds. Credit: Holmes Seed Co.
Cucurbits
May 3, 2016
New Cantaloupe, Pumpkin, And Squash Seeds Available
New varieties developed at the University of New Hampshire are the result of the longest continuous squash and pumpkin breeding program in North America. Read More
A herbicide screening trial in a non-bearing almond orchard treated in early January 2011.  The middle plot is a glyphosate-only program whereas the foreground and background plots had residual herbicides.  The photo was taken four months after the January treatments. (Photo credit UCANR)
Crop Protection
May 3, 2016
Almond Board To Hold Three Weed Management Workshops
The second in a series of free educational workshops aimed at the state’s almond growers will cover weed identification and Read More
fork digging into a plate full of salad
Food Safety
May 2, 2016
Department Of Justice To Investigate Dole Over Listeria Outbreak In Packaged Salads
Salad mix packaged at the company’s Ohio facility has been connected to four deaths. Read More
Florida Everglades swamp shot at sunset
Citrus
May 2, 2016
As Hurricane Season Nears, South Florida Going Dry
All basins around the region experience rainfall deficits during April as totals fall far below average. Read More
Harvesting Tips At Kuhn Orchards
Equipment
May 2, 2016
USDA Offers New Loans For Portable Farm Storage, Handling Equipment
Portable equipment can help producers, including small and local farmers, get products to market quickly. Read More
Contour Farming
Vegetables
May 2, 2016
The Importance Of Producing Crops On Well-Managed Cropland
Many farmland protection options and tools have been suggested and used in efforts to slow the rate of farmland losses around the country. Read More
Photo credit: USDA
Leafy Vegetables
May 2, 2016
Electronic Eye Detects Decay Inside Bagged Lettuce
Researchers develop a way to help select breeding lines that will yield cut lettuce with a longer shelflife. Read More
(Photo credit: USDA via Almond Board of California)
Nuts
May 2, 2016
California Almond Acreage Up 6%
The increase follows a trend in which acreage has doubled in the last 20 years. Read More
The Latest
Citrus
May 3, 2016
New Program Targets Abandoned California…
Bayer and California Citrus Mutual have teamed up to help protect the state’s commercial citrus industry from deadly citrus greening. Read More
Fruits
May 3, 2016
How To Build A Better Beetle Trap
UF/IFAS study on luring, snaring the notorious redbay ambrosia beetle earns prestigious award. Read More
Cucurbits
May 3, 2016
New Cantaloupe, Pumpkin, And Squash Seed…
New varieties developed at the University of New Hampshire are the result of the longest continuous squash and pumpkin breeding program in North America. Read More
Crop Protection
May 3, 2016
Almond Board To Hold Three Weed Manageme…
The second in a series of free educational workshops aimed at the state’s almond growers will cover weed identification and Read More
Food Safety
May 2, 2016
Department Of Justice To Investigate Dol…
Salad mix packaged at the company’s Ohio facility has been connected to four deaths. Read More
Citrus
May 2, 2016
As Hurricane Season Nears, South Florida…
All basins around the region experience rainfall deficits during April as totals fall far below average. Read More
Equipment
May 2, 2016
USDA Offers New Loans For Portable Farm …
Portable equipment can help producers, including small and local farmers, get products to market quickly. Read More
Vegetables
May 2, 2016
The Importance Of Producing Crops On Wel…
Many farmland protection options and tools have been suggested and used in efforts to slow the rate of farmland losses around the country. Read More
Leafy Vegetables
May 2, 2016
Electronic Eye Detects Decay Inside Bagg…
Researchers develop a way to help select breeding lines that will yield cut lettuce with a longer shelflife. Read More
Nuts
May 2, 2016
California Almond Acreage Up 6%
The increase follows a trend in which acreage has doubled in the last 20 years. Read More
Farm Management
May 2, 2016
USDA Unveils New Urban Agriculture Toolk…
For urban farmers and agribusiness entrepreneurs, the toolkit is an electronic document that helps users navigate more than 70 resources, including technical assistance and financing opportunities. Read More
Cucurbits
May 2, 2016
13 Of The Latest Cucumber Varieties
Check out this slideshow for more details on 13 cucumber varieties you need to know about from the nation’s leading seed breeders and Read More
Apples & Pears
May 1, 2016
USApple Debuts New Website
Industry group says new site is responsive to different formats, designed to be more consumer and industry friendly. Read More
Crop Protection
April 30, 2016
How To Elect The Right Fungicide For The…
Fungicide application is one tool of a successful IPM program for crop diseases. Used judiciously and appropriately, these chemicals are powerful allies in the fight against the fungi and bacteria that attack crops. Read More
GenNext Growers
April 30, 2016
Young Growers The Focus Of Industry Prog…
The next generation in the tree fruit industry getting support of leading industry organizations. Read More
Nuts
April 29, 2016
Look Out For Jacket Rot On Almond Leaves
Rains at bloom are causing higher than normal incidents of bacterial infections. Read More
Farm Marketing
April 29, 2016
Churchview Farm Aims To Close The Gap Be…
This year, from June through September, Churchview Farm, located just outside of Pittsburgh, will host four farm dinners a month, Read More
Farm Marketing
April 29, 2016
How Wholesale-Only Growers And Farm Mark…
We already know of some of the differences between farm marketers and wholesale-only farms. Farm marketers outnumber wholesale-only farms. Wholesale-only Read More
[gravityform id="62" title="false" description="false"]