University of Florida

42nd Annual Citrus Packinghouse Day

August 21, 2003

Citrus Research and Education Center
700 Experiment Station Road
Lake Alfred, FL 33850-2299

State of Florida Department of Citrus
Lakeland, FL

In cooperation with Florida Citrus Packers

Cooperative Extension Service
Institute of Food and Agricultural Sciences
University of Florida, Gainesville

Registration--8:30 AM
Program--9:30 AM

Packinghouse Day Coordinators

Mark Ritenour, Ph.D., Program Coordinator
Bill Miller, Ph.D., Exhibits Coordinator
Renée Goodrich, Ph.D., Local Arrangements Coordinator

Welcome to the Forty-Second Annual Citrus Packinghouse Day! This year we again have many important issues that will be addressed. Leading members of industry and scientists from the University of Florida, the Florida Department of Citrus, and the University of California will present practical and applied information of interest to your business.

This year’s keynote speaker is Dr. Mary Lu Arpaia from the University of California who will discuss recent changes in the California citrus industry. Other topics presented will include:

  • New citrus varieties for the fresh market
  • Factors influencing fruit shape (e.g. sheepnosing)
  • Factors influencing the arrival quality of early season citrus
  • Fungicide options for the future
  • Food safety issues for Florida citrus packinghouses
  • Fresh citrus overview: what's the market, who's the competition and where's the future?

Because of a generous donation from DECCO/Cerexagri, Inc., an excellent lunch will again be provided to the first 200 people to register at the door. Be sure to stop by DECCO’s exhibitor booth to say thanks! Representatives from more than 30 companies will be on hand to provide valuable information for your business. Check out what they have to offer after lunch. An exhibitor list will be provided including the names, addresses, telephone numbers and products sold.

Be sure to stick around for the door prize drawings. We will again be giving out $250 in door prizes. The only catch is that you have to be present to win. One of the door prizes will be given out in the exhibitor area. Also, please complete and turn in an evaluation form, they provide us valuable feedback on how we can improve Packinghouse Day. One of the door prizes will be awarded only to participants who turn in a completed evaluation form.

Mark A. Ritenour
Program Coordinator
Indian River Research and Education Center


8:30 AM Registration

9:30 AM Welcome

Dr. Harold W. Browning, Center Director , Citrus Research and Education Center, Lake Alfred

Introductory Remarks

Dr. M. Joseph Ahrens, Director of Scientific Research, Florida Department of Citrus, Lake Alfred


Dr. Brian T. Scully, Center Director, Indian River Research and Education Center, Ft. Pierce

10:00 AM Changes in the California Citrus Industry

Mary Lu Arpaia, University of California Kearney Agricultural Center, Parlier, CA
Keynote Speaker

10:30 AM New Variety Options for the Fresh Market

Richard Kinney, Florida Citrus Packers, Lakeland, FL
Harold Browning, UF/IFAS Citrus Research and Education Center, Lake Alfred, FL

Choosing new cultivars: What does the consumer want? Satsumas, Clementines, navel or Valencia, a cross between a grapefruit and banana? Industry is at a crossroads…do we continue to try to "sell" what we have or develop products or cultivars that the consumer wants? And, what "system" will help us meet identified near or long-term goals.

In our attempt to answer these questions, we will present new variety selection criteria and quantify new variety options. Such criterion includes brix-acid-ratio, ease of peeling, production, size of fruit, disease susceptibility or resistance, packability, color (on tree), marketable peel color, ease of section separation, and flesh color. Audience comment and discussion will be encouraged.

10:45 AM What are the Environmental and Tree Conditions that Cause Sheepnosing in Grapefruit?

J.P. Syvertsen, et al

Misshaped fruit, which are often predominantly sheepnosed, can reduce the packout of grapefruit by more than 20% in some years. Sheepnosing undoubtedly occurs while fruit are still on the tree but the underlying causes are not clearly understood. Many growers have different ideas as to what causes sheepnosed fruit but subsequent management practices to reduce sheepnosed fruit have not been consistent. Since not all sheepnosed fruit are elongated, the fruit height to width ratio was not a good quantitative measure of the shape of fruit that were visually rated as sheepnosed. Although there were more fruit borne singly than in clusters, clustered fruit had a higher percentage of sheepnosed fruit. Thus, sheepnosing may be related to high crop load since there are relatively more fruit borne in clusters than singly in high crop years. Shape rating in July was maintained until Nov in the majority of fruit. Overall fruit shape changes from oblong towards round or flat as it develops so very few round or flat fruit in July become sheepnosed by Nov. We have yet to evaluate changes in grapefruit shape from Nov through May. Elevating early season temperature in tree canopies by placing clear plastic tents over trees from before bloom until July, increased the percentage of sheepnosed fruit (14%) above that of the uncovered control trees (4%). Ruby red grapefruit trees fertilized at 250 lbs N/Ac per year had more sheepnosed fruit (14%) than trees that received 100 lbs N/Ac per year (3%). There were only small differences in the percentage of sheepnosed fruit in different grapefruit cultivars, rootstocks and canopy positions. If we can understand the mechanisms by which misshapen fruit occur, we may be able to minimize the problem or at least predict the onset of misshaped fruit as early as possible in a season.

11:00 AM Factors Influencing Quality of Early Season Florida Citrus

Mohamed A. Ismail and Huating Dou, Florida Department of Citrus, Citrus Research and Education Center, Lake Alfred, FL

Florida's hot, rainy summers and warm winter nights contribute to the production of sweet early-season citrus fruit with high Brix to acid ratio. Such fruit meet legal maturity standards while the peel is still green and immature. Cultural practices such as frequent irrigation, fertigation, high rates of nitrogen fertilization and high density planting may also result in early fruit maturation. Early season fruit are, however, more susceptible to physiological disorders, decay and mechanical injury; all of which reduce pack-out arrival quality and grower returns.

While climatic and environmental conditions’ impact on fruit maturity cannot be fully controlled, some cultural practices can be managed to reduce external blemishes, decay and disorders. The following preharvest measures are recommended to help improve pack-out and arrival quality:

  • Control melanose and rust mites to enhance external appearance
  • Reduce nitrogen fertilizer to promote color development
  • Apply appropriate fungicides prior to harvest to reduce disease pressure
  • Avoid excessive irrigation prior to harvest

Harvesting and Postharvest Practices

  • Allow development of sufficient color break prior to harvest in order to minimize degreening time and reduce peel injury. Poorly colored fruit are more susceptible to Anthracnose and require prolonged degreening which increases Stem-End Rot (SER)
  • Avoid harvesting after heavy rainfall and test fruit turgidity using a suitable penetrometer. Peel injury results in oil spotting and reduces pack-out
  • Clipping of tangerines and some varieties of Tangelos eliminates plugging
  • Closely supervise harvesting and never pick fruit off the ground

Precooling and Drenching

  • Drench with suitable fungicide to control SER and maintain pH and chlorine in the drench mix to recommended levels
  • Immediately cool fruit after picking to approximately 50oF if packing is delayed beyond 24 hours to avoid excessive decay caused by Anthracnose and SER.


  • Minimize degreening time, temperature and ethylene concentration
  • Degreening time varies with variety and degree of color break
  • Maintain high relative humidity in degreening room to avoid shriveling and weight loss
  • Allow one full fresh air exchange per hour and one full air circulation per minute.

Packinghouse Operations

To minimize injury to fruit between dumping and packing, the following measures are recommended:

  • Condition new brush beds to reduce mechanical injury to early season fruit
  • Assess physical injury potential of the packing line using the instrumented sphere or the Triphenyl tetra-zolium chloride (TTC) method
  • Apply suitable fungicides, separately and in the wax
  • Maintain dryer air temperature below 140oF
  • Apply carnauba or polyethylene wax to promote better gas exchange and prevent off-flavor development
  • Immediately store or ship fruit at low temperature to reduce peel pitting and decay.

For additional information on maintaining quality of early-season fruit, see articles by J. Zhang and H. Dou in the FDOC Postharvest website.

11:15 AM Potential New Fungicides for Fresh Citrus

John Zhang and Patricia Swingle, Florida Department of Citrus, Citrus Research and Education Center, Lake Alfred, FL

An effective postharvest decay control program is critical for maintaining fresh fruit quality, reducing postharvest losses, and ultimately increasing net returns to fresh citrus growers. Currently in Florida, citrus postharvest decay control is achieved through an integrated procedure using synthetic fungicides as the core component. Imazalil, thiabendazole (TBZ) and sodium o-phenylphenate (SOPP) are the only synthetic fungicides available to the citrus industry for the control of a wide array of postharvest fungal diseases. These three fungicides have been periodically reviewed by the EPA and their future availability will be affected by increasingly restrictive regulations and the development of pathogen resistance. Obviously, it is important to look for alternatives to Imazalil and TBZ.

In recent years, three new fungicides with different modes of action have been in process for EPA registrations for postharvest treatments of various fruits including citrus. They are PH066 (pyrimethanil), Scholar (fludioxonil), and Abound (azoxystrobin). The EPA has classified these three new chemicals as reduced risk compounds. PH066 is from Janssen Pharmaceutica Inc. which also manufactures Imazalil, and Scholar and Abound are both from Syngenta Inc., the manufacturer of TBZ. PH066 is scheduled to be reviewed this year by the EPA and labeled next year. Abound and Scholar are scheduled to be reviewed by the EPA in 2004 and labeled in 2005.

Tests on these three new compounds were conducted by the FDOC to determine their potential for postharvest decay control of Florida citrus using different varieties and methods. The tests showed that both Abound and Scholar significantly reduced stem-end rot (Diplodia natalensis) and green mold (Penicillium digitatum) using simulated drench and packingline application methods. Scholar appears to be a good alternative to TBZ since its decay control spectrum and efficacy are similar to those of TBZ. Drench application of Scholar at low rates (100 to 500 ppm) was very effective for stem-end rot control. In addition, Scholar was the only compound showing a significant reduction of anthracnose (Colletotrichum gloeosporioides) in one test using ‘Fallglo’ tangerines. The tests of PH066 were conducted under a confidentiality agreement between the FDOC and Janssen, thus the results can not be shown at this time. However, the new chemicals appear to be less or slightly less effective than Imazalil and TBZ for the control of green mold and stem-end rot, respectively.

The registrations of these three new fungicides will not replace the current fungicides (TBZ, Imazalil and SOPP), but will provide additional chemical tools for postharvest decay control and the management of pathogen resistance. Since TBZ and Imazalil are excellent materials for effective control of both stem-end rot and molds, and with no obvious pathogen resistance problems reported in Florida packinghouses, TBZ and Imazalil should still be the best choices for postharvest treatments. However, the new chemicals would obviously become important to our fresh citrus industry if either TBZ or Imazalil is removed due to new restrictive regulations or becomes less effective due to the development of severe pathogen resistance.

11:30 AM Citrus Packinghouse Food Safety--The Latest Issues

Renée Goodrich, UF/IFAS Citrus Research and Education Center, Lake Alfred, FL

Starting with the President’s Food Safety Initiative in 1997, there has been a heightened interest in produce-related food safety issues. An increase in per capita fruit and vegetable consumption in the past decade, coupled with several high-profile foodborne disease outbreaks related to produce, has led to continued regulatory and scientific focus on fresh and fresh-cut fruit and vegetable food safety and security.


Good Agricultural Practices (GAPs) have been the cornerstone programs in produce food safety for the past 5 years. Since 1998, when these federal guidance documents were issued by the U.S. Food and Drug Administration (FDA), most major producers and packers have adopted GAPs programs. Impetus for change was the realization that produce food safety was a real concern for consumers and regulators alike. Additionally, many producers/ packers instituted GAPs programs to achieve and/or maintain preferred vendor status with important customers.

Important components of GAPs programs include assessing the following aspects of production and packing, as appropriate for a given operation:

  • Water
    • Agricultural water source and distribution
    • Historical use of land
    • Wells properly maintained
    • Processing water is tested regularly
    • Cooling water and ice are clean and sanitary
  • Worker Health and Hygiene
    • Employees properly trained in good hygienic practices
    • Re-assignment of ill employees to non-food handling duties
    • Proper use of gloves
    • Proper management and stocking of field toilets
    • Be familiar with laws and regulations that might apply to field sanitation facilities such as state laws and OSHA
  • Field and Packing Facility Sanitation
    • Storage facilities and bins cleaned before use
    • Do not re-contaminate produce that is washed, cooled or packed
    • Maintain temperature that promotes optimum produce quality and minimize pathogen growth
    • Assign responsibility for equipment cleaning and maintenance
    • Remove as much dirt as possible outside packing area
    • Establish and maintain pest control program in packinghouse
  • Transportation and Traceback
    • Transportation vehicles inspected for cleanliness, odor and debris before loading
    • Maintain proper transport temperatures
    • Be able to trace produce containers from the farm, to the packer, distributor and retailer
    • Document date of harvest, farm identification and who handled produce

Much useful and practical information regarding produce safety and GAPs can be found at the following FDA website:

Food Security and the Bioterrorism Act of 2002

September 11, 2001 was a wake-up call for American citizens and businesses. The nation’s food supply has been identified as a critical network and a possible target for terrorist activities. This portion of the presentation will focus on summarizing the Bioterrorism Act of 2002 as it relates to fresh fruits and vegetables, including citrus. Some producers, and all packers, will face new record keeping requirements in light of this recent legislation. The specific requirements of Facility Registration and Prior Notice will be reviewed, and some food security self-auditing information will be provided.

A valuable resource for background information regarding food security, bioterrorism, and the specific requirements of the Act can be found at:

11:45 AM The Economics of the Fresh Citrus Industry

Tom Spreen, UF/IFAS Food and Resource Economics Department, Gainesville, FL

The U.S. fresh citrus industry has been buffeted by several factors including increased imports, increased competition from other fresh fruits, and adjustment to trade agreements. Recent events in the fresh citrus sector are discussed. The implications of emerging trends are highlighted.