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

UncategorizedRispens Seeds Highlights Their Latest Vegetable Varieties
December 18, 2014
For more information, contact: Rispens Seeds 1357 Dutch American Way, P.O. Box 310, Beecher, IL 60401 708-946-6560; 888-874-0241; fax: 708-946-6115 Read More
Protected Agriculture2014 Marks The 50th Anniversary Of The Double-Poly Greenhouse [sponsor content]
December 18, 2014
Double-poly greenhouses revolutionized the greenhouse industry back in the 1960s, opening the way for developments that still impact the industry 50 years later. Read More
CitrusSouthwest Florida Citrus Bus Tour Yields Learning Opportunity
December 18, 2014
Find out what Florida Grower editor Frank Giles saw and heard during Peace River Valley Citrus Growers Association's annual outing. Read More
Fruits6 Food Trends For 2015
December 17, 2014
University of Florida experts predict what will be cooking for the upcoming year. Read More
VegetablesReed’s Seeds Showcases Their Latest Vegetable Variety Offerings
December 17, 2014
For more information, contact: Reed’s Seeds 3334 NYS 215 Cortland, NY 13045 607-753-9095; fax: 607-753-9511 rsjackie@twcny.rr.com Read More
CitrusStudy: Florida Citrus Valued At More Than $10 Billion
December 17, 2014
Industry continues to have large impact on the state’s economy. Read More
Apples & PearsNovember Cold May Hurt Washington Orchards
December 17, 2014
But it’s too early to tell if well-below-normal temperatures will increase tree mortality. Read More
NutsAlmond Growers Lose Trees In Storm
December 17, 2014
Last week’s welcome rains in California knocked down trees, especially older ones. Read More
NutsAlmond Conference Draws Record Attendance
December 17, 2014
Nearly 3,000 industry professionals attend 42nd annual event in Sacramento, CA. Read More
Insect & Disease UpdateManage HLB From The Bottom Up
December 17, 2014
Finding the right balance between the roots and shoots is critical to disease mitigation. Read More

The Latest

UncategorizedRispens Seeds Highlights Their Latest Vegetable Varieti…
December 18, 2014
For more information, contact: Rispens Seeds 1357 Dutch American Way, P.O. Box 310, Beecher, IL 60401 708-946-6560; 888-874-0241; fax: 708-946-6115 Read More
Protected Agriculture2014 Marks The 50th Anniversary Of The Double-Poly Gree…
December 18, 2014
Double-poly greenhouses revolutionized the greenhouse industry back in the 1960s, opening the way for developments that still impact the industry 50 years later. Read More
CitrusSouthwest Florida Citrus Bus Tour Yields Learning Oppor…
December 18, 2014
Find out what Florida Grower editor Frank Giles saw and heard during Peace River Valley Citrus Growers Association's annual outing. Read More
Fruits6 Food Trends For 2015
December 17, 2014
University of Florida experts predict what will be cooking for the upcoming year. Read More
VegetablesReed’s Seeds Showcases Their Latest Vegetable Var…
December 17, 2014
For more information, contact: Reed’s Seeds 3334 NYS 215 Cortland, NY 13045 607-753-9095; fax: 607-753-9511 rsjackie@twcny.rr.com Read More
CitrusStudy: Florida Citrus Valued At More Than $10 Billion
December 17, 2014
Industry continues to have large impact on the state’s economy. Read More
Apples & PearsNovember Cold May Hurt Washington Orchards
December 17, 2014
But it’s too early to tell if well-below-normal temperatures will increase tree mortality. Read More
NutsAlmond Growers Lose Trees In Storm
December 17, 2014
Last week’s welcome rains in California knocked down trees, especially older ones. Read More
NutsAlmond Conference Draws Record Attendance
December 17, 2014
Nearly 3,000 industry professionals attend 42nd annual event in Sacramento, CA. Read More
Insect & Disease UpdateManage HLB From The Bottom Up
December 17, 2014
Finding the right balance between the roots and shoots is critical to disease mitigation. Read More
VegetablesVariety Trials 2014: Seedway
December 17, 2014
As part of American Vegetable Grower’s (AVG) 2014 variety trial coverage, we visited Seedway’s seed trial at Spiral Path Organic Farm in Loysville, Read More
OrganicUSDA Proposes Expansion Of Organic Assessment Exemption
December 17, 2014
Action would increase the entities exempt from paying assessments for promotion programs on products certified as “organic” or “100% organic.” Read More
MarketingThe U.S. Potato Board Receives $5 Million In Funding To…
December 17, 2014
The funds will be used to help increase consumption of frozen, dehydrated, chip stock, table stock and seed potatoes around the world. Read More
ProductionNational Vegetable Grafting Symposium To Take Place Jan…
December 17, 2014
The third grafting symposium, Growing New Roots for the Vegetable Industry in the U.S., will be held at the Savannah International Trade and Convention Center in Savannah, GA. Read More
VegetablesOutstanding Seed Co. LLC, Showcases Their Latest Vegeta…
December 16, 2014
For more information, please contact: Outstanding Seed Company, LLC P.O Box 202 Monaca, PA 15061 877-248-4567; fax: 724-775-1644 outstandingseed.com Read More
VegetablesJohnny’s Selected Seeds Showcases Their Latest Ve…
December 16, 2014
For more information, please contact: Johnny’s Selected Seeds 955 Benton Ave. Winslow, ME 04901 877-564-6697; fax: 800-738-6314 johnnyseeds.com Read More
Apples & PearsFour Highlights You May Have Missed At Great Lakes Expo
December 16, 2014
Record-setting crowd sat in on presentations featuring precision orchard management, mechanical berry harvesters, biocontrols, and more. Read More
FruitsGrower Input Needed For Spotted Wing Drosophila Survey
December 16, 2014
Results of stakeholder needs survey helps prioritize research and education activities. Read More