INTRODUCTION TO THE MANUAL

1. Introduction

The three main objectives of applying postharvest technology to harvested fruits and vegetables are:

1. to maintain quality (appearance, texture, flavor and nutritive value)
   
2. to protect food safety, and
   
3. to reduce losses between harvest and consumption.

Effective management during the postharvest period, rather than the level of sophistication of any given technology, is the key in reaching the desired objectives. While large scale operations may benefit from investing in costly handling machinery and high-tech postharvest treatments, often these options are not practical for small-scale handlers. Instead, simple, low cost technologies often can be more appropriate for small volume, limited resource commercial operations, farmers involved in direct marketing, as well as for suppliers to exporters in developing countries.

Many recent innovations in postharvest technology in developed countries have been in response to the desire to avoid the use of costly labor and the desire for cosmetically "perfect" produce. These methods may not be sustainable over the long term, due to socioeconomic, cultural and/or environmental concerns. For example, the use of postharvest pesticides may reduce the incidence of surface defects but can be costly both in terms of money and environmental consequences. In addition, the growing demand for organically produced fruits and vegetables offers new opportunities for small-scale producers and marketers.

Local conditions for small-scale handlers may include labor surpluses, lack of credit for investments in postharvest technology, unreliable electric power supply, lack of transport options, storage facilities and/or packaging materials, as well as a host of other constraints. Fortunately, there is a wide range of simple postharvest technologies from which to choose, and many practices have the potential of meeting the special needs of small-scale food handlers and marketers. Many of the practices included in the manual have successfully been used to reduce losses and maintain produce quality of horticultural crops in various parts of the world for many years.

There are many interacting steps involved in any postharvest system. Produce is often handled by many different people, transported and stored repeatedly between harvest and consumption. While particular practices and the sequence of operations will vary for each crop, there is a general series of steps in postharvest handling systems that will be followed for the purposes of the manual.

Chapter 1 presents some harvesting practices and methods of preparation of fresh produce for market. Chapter 2 provides selected examples of how to cure root, tuber and bulb crops before further handling or storage. Chapter 3 illustrates simple technologies that can be used in the packinghouse, be it a simple shed in the field or a separate structure with cooling and storage facilities.

Chapter 4 presents a variety of packing methods and packaging materials that can help to maintain product quality and reduce mechanical damage during handling, transport and storage. Chapter 5 describes pest control methods and offers suggestions for alternatives to chemical treatments for insect and disease control.

Simple methods for cooling produce are described in Chapter 6. Storage structures, methods for ensuring adequate ventilation, and simple technologies for modified atmosphere storage are presented in Chapter 7. Transport practices that can reduce losses are described in Chapter 8, and methods for handling at destination (wholesale or retail markets) are illustrated in Chapter 9. Chapter 10 presents some simple methods for processing fresh produce such as adding value by drying, canning and juice extraction. Finally, Chapter 11 is a new chapter for this edition of the manual, and describes the basics of Good Agricultural Practices (GAP) and simple methods that can be applied to ensure food safety for fresh produce.

Each of the practices presented in the manual are briefly described and illustrated. For further information on any particular practice, users can refer to the source listed or write directly to the authors of the manual. The practices described in this manual are not meant to be a comprehensive list of postharvest handling practices, but a starting point for low-input and/or small-scale handlers of horticultural commodities. We suggest that you try the practices and compare them to your current practice. Remember that any of the practices may be modified by handlers to better suit the local conditions or materials available. And it is our hope that users of the manual will send to the authors any information about practical, low cost technologies currently in use which were not covered in this edition.

We believe that application of some of the simple practices illustrated in the manual will enable small-scale handlers to reduce produce losses, protect food safety and help maintain quality of fruits, vegetables and ornamental crops .

Figure 1: Postharvest Handling Steps for a Typical Commodity

Principal causes of postharvest losses and poor quality

Despite decades of educational efforts, the most common causes of postharvest losses in developing countries continue to be rough handling and inadequate cooling and temperature maintenance. The lack of sorting to eliminate defects before storage and the use of inadequate packaging materials further add to the problem. In general, minimizing rough handling, sorting to remove damaged and diseased produce and effective temperature management will help considerably toward maintaining a quality product and reducing storage losses. Storage life will be enhanced if the temperature during the postharvest period is kept as close to the optimum as feasible for a given commodity

Relative perishability and storage life of fresh produce

Classification of fresh horticultural crops according to their relative perishability and potential storage life in air at near optimum temperature and relative humidity.

Source: Kader, A.A, 1993. Postharvest Handling. In: Preece, J.E. and Read, P.E., The Biology of Horticulture- An Introductory Textbook. New York : John Wiley & Sons. pp. 353-377.

Resources for Quality Assurance and Export Marketing

For handlers who desire more detailed information on requirements for export, the Natural Resources Institute (1994) has published a comprehensive Manual for Horticultural Export Quality Assurance. NRI's manual provides practical guidelines for the total quality management of the postharvest process, including inspections, hygiene, pesticide residue analysis, standardization of instruments for temperature checking, and records maintenance. This manual is highly recommended to anyone involved in the business of exporting horticultural commodities to countries of the European Union. (Available for sale from NRI, Central Avenue , Chatham Maritime , Kent ME4 4TB , UK ).

Standards for U. S. Grades are available for a wide range of fruits and vegetables for fresh market or processing. For a single free copy of U.S. Grades for a particular commodity, write to Fresh Products Branch, USDA-AMS, FV, Room 2056-S, Washington, D.C., 20250. U.S. Inspection Instructions are also available at a small fee from this address. Grade Standards can also be downloaded from the USDA-AMS website: http://www.ams.usda.gov/standards/stanfrfv.htm (Fruit & Vegetable Programs).

The Organization of Economic Cooperation and Development (OECD) publishes booklets on "International Standards of Fruits and Vegetables". In North America , write to: OECD Publications and Information Center , 2001 L Street, N.W., Suite 700 , Washington , D.C. , 20036-4910 . From countries outside North America , contact OECD Publications Service, 2 Rue André-Pascal, 75775 PARIS Cedex 16, France.

Food safety has lately become a top priority for many retailers, who are working toward the establishment of global Good Agricultural Practices (GAP). Started as an initiative by retailers in 1997, the Euro-Retailer Produce Working Group (EUREP), the current version of the EUREP-GAP document and procedures has been agreed among partners from the entire food chain for fruits and vegetables after a wide consultation phase over three-years. A draft document for certification, "EUREP-GAP Fruits and Vegetables", has been developed by a European group of representatives from all stages in the fruit and vegetable sector with the support from producer organizations outside the EU. Producer organizations from all continents have applied for EUREP-GAP membership and are beginning to utilize integrated and cost effective solutions delivering assurance of food safety.(http://www.eurep.org)

The mission of the Animal and Plant Health Inspection Service (APHIS) is “to protect America 's animal and plant resources by:

• Safeguarding resources from exotic invasive pests and diseases,
• Monitoring and managing agricultural pests and diseases existing in the United States ,
• Resolving and managing trade issues related to animal or plant health, and
• Ensuring the humane care and treatment of animals.”

The APHIS website (http://www.aphis.usda.gov/) offers a wide variety of information related to import/export regulations of concern to those interested in exporting produce to the United States .

• http://www.aphis.usda.gov/ppq/manuals/online_manuals.html displays a list of APHIS/Plant Protection and Quarantine Manuals that are available electronically.
  
• http://www.aphis.usda.gov/ppq/manuals/pdf_files/20Fruits_and_Vegetables.pdf is a complete handbook on “Regulating the Importation of Fresh Fruits and Vegetables” that is available online.

Protrade advises and promotes businesses in Latin America , Africa , Asia and Eastern Europe by providing marketing expertise for products that are competitive in European markets. Handbooks on general trade and marketing are available for fresh fruit and dried fruit. Export manuals (in English and Spanish) are available for asparagus, mangoes, avocados, papaya and pineapple. These publications are available from Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ), Gmb H/ Protrade, P.O. Box 5180 , D-65726 Eschborn, Germany .

Publications on the harvesting, postharvest handling and marketing of banana, mango, rambutan, papaya and durian are available from the ASEAN Food Handling Bureau, as a part of its series on "Fruit Development, Postharvest Physiology, Handling and Marketing in ASEAN". Each book is available for sale from ASEAN Food Handling Bureau, Level 3, G14/G15, Pusat Bandar Damansara, 50490 Kuala Lumpur , Malaysia .

Membership in ProduceWorld is free of charge, and members can list their produce for sale online or search ProduceWorld’s classified listings for brokers or wholesalers interested in buying and/or selling fresh or processed produce. (www.produceworld.com)

The Produce Marketing Association, founded in 1949, is a not-for-profit global trade association serving over 2,400 members who market fresh fruits, vegetables, and related products worldwide. Its members are involved in the production, distribution, retail, and foodservice sectors of the industry. ( www.pma.com)