Mary Kenny is Nutrition Officer (Quality Assurance) in the Food Quality
and Standards Service, FAO Food and Nutrition Division.
Fruits and vegetables make a significant contribution to food security and are an important component in a healthy diet. An increasing body of literature is accumulating that highlights the role of fresh produce in providing anti-oxidants and other compounds that may lower the risk of cancer and other chronic diseases such as heart disease. Nutritionists in many countries have education campaigns to promote consumption of fruits and vegetables for their health benefits.
This increased emphasis on health and consumer choice, together with other factors, such as geographical re-location of the consumer, food-processing technologies and improved transportation and communication networks, has led to changes in world market opportunities for fruits and vegetables. Improvements in post-harvest technologies and cold chains during transportation have facilitated international trade and increased the availability of a wide range of fruits and vegetables (Pollack, 2001).
International trade has provided producing countries with the possibility to access new and larger markets and gain income from foreign earnings. The value in US$ of the export trade from developing countries of fresh and processed fruits and vegetables increased during the 1980s and 1990s. Since 1995, the growth rate has been constant (FAO, 2002). The increases in international trade are significant in terms of economic benefit, but also affect dietary intake and consumption through greater availability and a wider choice of foods. Produce associated with tropical countries (e.g. mangoes, avocados, passion fruit) is now com-monly for sale worldwide.
The types of fruits and vegetables traded include basic tubers and roots (potatoes, yams, plantains and so on) and fresh fruits in unprocessed and ready-to-eat (RTE) forms. The supply-and-demand chain has also been influenced by niche markets, such as the organic movement.
To be competitive, producers must comply with the requirements of the World Trade Organization (WTO) relating to market access and sanitary requirements, and must consider the importing country's requirements. Producers and governments alike have responded by implementing a variety of standards and quality assurance schemes to ensure the quality and safety of fresh fruits and vegetables. The standards include national and international requirements targeted to strengthen good agricultural practices (GAPs) and good hygienic practices (GHPs) along the total chain as part of quality assurance programmes. The importance of safe food has gained increased priority due to recent outbreaks of food-borne illnesses, including some large international outbreaks associated with fresh fruits and vegetables. Consumers demand assurance that the food they and their families are eating is safe, of good quality and nutritious. Domestic and imported foods should meet these basic standards. This article focuses on the quality and safety aspects of producing fresh fruits and vegetables, as an integrated component in the production chain.
In discussing a healthy diet, it is inher-ently assumed that consumers, while receiving adequate nutrients, will not develop food-borne illnesses as a result of the food eaten. To meet this expectation, fruits and vegetables should be produced under conditions that meet the relevant quality and safety criteria. However, data show that the food we eat can be contaminated by microbiological and chemical hazards.
Traditionally, fresh fruits and vegetables have not been considered high-risk foods in terms of causing food-borne illness, especially when compared with foods of animal origin (meat, dairy products and seafood). The general assumptions have been that the pH of fruits and vegetables was too low to support the growth of human disease-causing pathogens, and that the natural barriers of the fruits and vegetables would prevent microbes from entering and subsequently growing inside the food (Beuchat, 1996; Madden, 1992). Nonetheless, the relationship between fresh produce and so-called "travellers' diarrhoea" has frequently been observed; this ailment is sometimes contracted when people travel away from their home country and encounter different foods with different microflora.
The assumptions relating to the relative lower risk of fresh produce have been somewhat modified as a result of recent epidemiological data and the adverse publicity associated with outbreaks of food-borne illnesses at national and international levels due to fresh produce. According to the Center for Disease Control and Prevention in the United States of America, the number of produce-associated outbreaks of illness per year in the United States doubled between 1973 and 1987 and between 1988 and 1992 (Olsen et al., 2000). Data from the Public Health Laboratory Service (PHLS) in the United Kingdom show that between 1992 and 1999, 60 outbreaks of food-borne infectious intestinal diseases associated with the consumption of salad items, fruits and vegetables were reported from England and Wales. The out-breaks affected 2 170 people, and 27 were admitted to hospital. In 17 of the outbreaks, more that 50 people were simultaneously affected.
Several reasons have been given to explain these increases in large outbreaks, including the evolution of more pathogenic forms of bacteria that can now survive refrigeration and more acidic conditions. Changes in production practices and increased numbers of people handling the same produce may be other factors (Thayer and Rajkowski, 1999). Recent outbreaks have indeed raised the need for stricter food-safety controls to be applied to fresh produce along the chain.
In terms of chemical contamination, much has been done in the past to improve GAPs for pesticide usage, banning of dangerous pesticides and improvement of quality standards. The programmes put into action need to be continually enforced and monitored to ensure that good practices are implemented as part of on-farm quality assurance programmes, and that food is not excessively contaminated at the pre-harvest stage.
The highly publicized outbreaks of food-borne illness associated with fresh fruits and vegetables have focused international attention on implementing appropriate controls along the food production chain. A review of scientific literature shows that food safety hazards are varied and may be introduced at different points along the chain - implicated fruits and vegetables have included both imported and local produce.
Two cases will illustrate the diverse sources of food safety hazards, and a range of mechanisms by which they are introduced to the fresh fruits and vegetables.
Cases of food poisoning from chemical contamination of food have also been reported. The national press in Viet Nam reported that 63 people died from food poisoning out of the 3 184 cases reported in 2001. Some of these cases have been attributed to high levels of pesticides. These cases along with other scientific literature show that food safety hazards originate in a range of sources. These include: i) the environment: the land where the produce is grown and harvested; ii) agricultural practices used in the production cycle: water sources, fertilizers, pesticides and organic manures; and iii) harvesting and post-harvest equipment and on-farm facilities. During food preparation and retailing, hazards may be introduced through poor handling and hygienic practices or by cross-contamination from other contaminated foods or chemicals.
To ensure the quality and safety of fresh fruits and vegetables, producers and government implement standards based on good hygiene and good agricultural practices, along the production chain
The likelihood of microbial hazards being introduced is increased where there is greater handling of the produce. For this reason, fruits and vegetables prepared as RTE are often considered to be higher-risk products. Cutting, slicing, skinning and shredding removes or damages the protective surfaces of the plant or fruit. Subsequently, pathogens can be spread from the outer surface of the food, from the food handler or from contaminated equipment, the slicer, cutter and so on (European Commission, 2002). The presence of pathogens in sprouted seeds, e.g. mung beans, soybeans and alfalfa seeds, has also been reported to create a potential hazard. The conditions under which they are sprouted (growing time, temperature, moisture and nutrients) are ideal for bacterial proliferation (Feng, 1997; Taormina, Beuchat and Slutsker, 1999). Salmonella and E. coli 0157:H7 are most commonly linked with sprout-associated outbreaks.
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The lack of a processing step by the food processors or consumers, such as heat treatment, reduces the opportunity to remove microbial hazards from fresh and RTE fruits and vegetables. Inter-national and national focus is on the prevention or reduction of risk through strengthened quality-assurance pro-grammes based on GAPs and GHPs. These programmes are to be applied along the production chain (pre-harvest, harvest and post-harvest) from the farm to the final consumer.
The basic principles to be respected in order to grow clean, safe, fresh produce apply to all types of agricultural production including home gardens, urban agriculture, wild plots and organic agriculture ranging in size from small to large farms. In all situations, GAPs and GHPs, appropriate to the production and processing environment, should be applied.
The "farm-to-fork" approach requires the assessment of conditions at primary production, storage, distribution, processing, handling and retailing to the final consumer. All stakeholders in contact with food along the food supply chain - growers, processors, packers, shippers, exporters, distributors, retailers, transporters, other food handlers and, finally, consumers - must practise good food safety procedures. To be optimally effective, the formation of linkages between these stakeholders should be encouraged to ensure a continuum of safe food.
Properly applied, GAPs are important for a sustainable approach to agriculture, prevention of environmental contamination, preservation of waterways and non-contamination of soil.Land and environment. In choosing a site for planting and growing food, the soil itself should be free from excess contamination, and the land should be situated so that it is not subject to contamination from adjoining activities, such as municipal waste disposal, industrial or other farming activities, livestock husbandry, to name but a few.
Water. Water, including from irrigation systems, may potentially contaminate food because it can carry micro-organisms, agricultural residues, heavy metals and other contaminants. The quality of the water should be suitable for the intended use, which must be considered when selecting the source of water. Steps should be taken to prevent contamination of the water source.
Agricultural inputs. Best practices need to be followed in the use of all agricultural inputs, including pesticides and fertilizers. These include the use of authorized chemicals for the crop, in accordance with the manufacturer's instructions so as to prevent excess residues in the food. Growers should keep records of agricultural chemical applications.
Organic manures. The application of organic manures, biosolids and other natural fertilizers should be managed to limit the potential for microbiological, chemical and physical contamination. Their use is common in many countries, and provides a source of nutrients to the crop. Good practices, taking into consideration the planting system and crop type, should be adopted for composting treatment procedures, application procedures, time to harvest and related activities.
Practices relating to farm workers. Workers on farms who are in contact with fresh fruits and vegetables need to observe GHPs in order to ensure that produce does not become excessively contamin-ated. Issues related to personal hygiene, use of equipment and handling practices must be taken into consideration. Equipment and containers in contact with produce should be made of non-toxic materials and kept clean. The provision of adequate facilities for toilet use and hand-washing is necessary to ensure that fruits and vegetables are handled hygienically. Work practices should also be adopted in order to prevent cross-contamination, accumulation of waste matter and pests and so on.
The handling of any food, including fruits and vegetables, requires the application of GHPs appropriate to the stage of production along the food chain, which includes activities carried out on the farm, in packing houses, processing and retail units, and in homes by consumers. The scope of GHPs has been described in the Codex General Principles of Food Hygiene (FAO/WHO, 2001) and includes the following.
Water supply. Water should not be a source of micro-organisms - an adequate, potable supply should be provided. In some instances, for example where fruits and vegetables are prepared as RTE products, good hygiene practices should receive particular attention, so as to minimize microbial food safety hazards.
Facilities and equipment, packinghouses. Adequate facilities, suitable to the type of process, should be made available. Equipment should be maintained in a clean condition and not provide a source of contamination.
Cleaning facilities. Adequate facilities should be provided to maintain the premises and equipment in a hygienic condition. Chemical agents in contact with fruits and vegetables should not contaminate the product. A cleaning schedule setting out frequency, method of cleaning and other details should be maintained.
Employee hygiene. As above, food hand-lers should adopt best practices to prevent contamination of produce, directly or through cross-contamination. Appropriate hygiene facilities should be made available for employees, including toilet and hand-washing facilities. Correct handling practices should be implemented to ensure proper temperature control, prevent cross-contamination, and verify process and packaging requirements.
Storage facilities. Adequate storage facilities should be provided and should not be a source of contamination. These include facilities used during the transportation of the produce, e.g. open trucks or refrigerated containers. When in storage, produce should be stored in suitable packaging to maintain quality and safety.
Pest control and waste. The premises should be maintained clean, and waste should be properly disposed of to prevent pest infestations. When necessary, measures taken to control pests should be safe, and adequate records maintained of treatment and type of infestation. The premises should be properly secured to prevent or minimize pest access.
Producers and governments alike have responded in the interest of consumer protection by developing policies to encourage and support the strengthening of quality assurance within the fruit and vegetable industry. A certain number of national initiatives, including regulatory or voluntary schemes to promote food quality and safety, have already been promoted (see Box 1).
BOX 1 National initiatives UNITED STATES IRELAND INDIA |
In addition to national response, the international community has developed international standards on quality and, more recently, on the safety aspects of fresh fruits and vegetables through the Codex Alimentarius Commission (CAC). The standards are developed to protect consumers and facilitate international trade. Produce from one country is often refused access to foreign markets owing to poor quality and safety, or because of the presence of pests. In response to the latter, the International Plant Protection Convention (IPPC) has developed standards relevant to plant protection.
International standards are significant because they set minimum controls and common rules for trading of fruits and vegetables, and in this respect they assist national policy-makers. The World Trade Organization (WTO) Agreement on Sanitary and Phytosanitary Measures (SPS) has encouraged member countries to base their SPS measures on internationally-developed standards, in order to ensure their scientific justification and advance the harmonization of sanitary and phytosanitary requirements. The standards of CAC and IPPC are the reference "benchmark" standards on food safety and plant protection, respectively (see Box 2).
Challenges to countries in meeting these standards, especially developing countries, need to be addressed at national and international levels. Where a contravention occurs at the national or international level, such as an outbreak of food-borne illness or the spread of a pest from one country to another, particular industries, as well as national reputations, can be detrimentally affected.
BOX 2 International standards related to fresh produce STANDARDS OF THE CODEX ALIMENTARIUS COMMISSION (CAC) (http://www.codexalimentarius.net/) QUALITY ASPECTS SAFETY ASPECTS INTERNATIONAL PLANT PROTECTION CONVENTION STANDARDS ON THE INTERNATIONAL PHYTOSANITARY PORTAL |
The production of fruits and vegetables, as well as the development of a strong national industry, are complex national policy issues that should be addressed in an integrated manner. The scope of the national policy should include food sold on the domestic market (locally grown and imported) and food that is exported so as to ensure that the produce is safe and wholesome when it reaches the final consumer. Fruits and vegetables sold on domestic and international markets should comply with national regulations and controls and importing-country requirements when produce is exported. National policy should promote the consumption of home-produced fresh fruits and vegetables on the domestic market through dynamic markets and supply chains, quality and safety controls of product and use of available technology, as required.
The national policy may target proper market supply, effective post-harvest technologies, appropriate transportation methods, an organized agricultural workforce and suitable food quality and safety controls at each step along the chain, among other components. When the fruit and vegetable chain from farmer to retailer is a strongly organized industry, controls for food quality and safety may be more easily promoted.
The initiation of quality and safety programmes in a producing country typically follows well-defined steps. The first step is to work with stakeholders within the country to develop standards that would ultimately lead to the introduction of appropriate legislation or voluntary standards. Programmes for food quality and safety will be promoted where the fruit and vegetable industry is healthy, robust and adequately supported by the national government (with actions including inspection and analytical capabilities). Additional steps to support international trade include government assistance in strengthening food quality and safety programmes within the industry, provision of training and technical information on existing controls and import requirements, and a strong regulatory system that can support and provide adequate inspection, analysis and certification.
Recent success stories of food quality and safety measures integrated into the production chain have been based on the strengthening of linkages between stakeholders in the food chain through contract farming and the establishment of commodity chains; for example, farmers become more closely linked to the supply market, with agreements between hotels/supermarkets and the producer. Measures like these increase accountability from one stakeholder to the next, and this is perhaps the reason for their success.
To ensure that food quality and safety are successfully integrated all along the chain, the training and/or assistance provided to the stakeholders should be appropriate to their needs and system of production. The initial responsibility of the farmer has been highlighted with a clear role in prevention as the primary producer through GAPs and GHPs. In many developing countries, the small farmer needs government help and support to assure safety and quality of fresh produce.
To be effective, farmers' responsibilities in producing safe, high quality food free from pests should not be considered in isolation from the other factors that influence the marketability of the products, including crop selection, transportation, and access to markets. Education initiatives for food safety need to be integrated in harmony with other similar information on improving agricultural outputs and market access.
The fruit and vegetable industry in producing countries, with the economic benefits that accrue from trade on national and international markets, is enhanced when the safety and quality of produce have been assured. This assurance can only be given where appropriate controls have been built into all points of the production chain. Because today there is increasing demand for fresh fruits and vegetables as part of a healthy, balanced diet, and because consumers demand increased food safety, the responsibility of the food industry as a supplier of safe food is clear.
It is possible to take preventive action through food safety management systems, such as GAPs, GHPs and Hazard Analysis Critical Control Point (HACCP) systems. FAO training courses have provided expertise on appropriate best practices to be applied to enhancing the quality and safety of fresh produce (see Box 3). Finally, to be fully effective, partnerships and collaboration between producers, government and consumers should be encouraged and strengthened.
BOX 3 FAO technical assistance FAO TRAINING COURSES
El Salvador, Guatemala, Honduras, Nicaragua and Panama, 30 September-25 October 2002 (four days each). A joint workshop coordinated by the Food Quality and Standards Service and Post Harvest Management Group. Practical aspects of post-harvest handling to maintain quality and safety of fresh fruit and vegetables in CARICOM region, Jamaica, 13-15 March 2002. FAO TECHNICAL ASSISTANCE - CROSS-SECTORAL
Within FAO, the multidisciplinary approach across these technical areas is being strengthened through the work of the priority areas for interdisciplinary action (PAIA) on Integrated Production Systems, including good agriculture practices (GAPs). http://www.fao.org/prods/index.asp?lang=en |
Improving the quality and safety of fresh fruits and vegetables: A training manual for trainers.
This manual has recently been published in English and Spanish by the Joint Institute for Food Safety and Applied Nutrition (see http://www.jifsan.umd.edu/gaps.html). The scope of the manual is the application of GHPs and GAPs for fruit and vegetable production along the chain. The FAO Food and Nutrition Division coordinated the input of a multidisciplinary team of FAO reviewers. The manual provides an overview of the issues to consider in developing programmes and training materials on GHPs and GAPs in the interests of food safety.
References
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European Commission, Health & Consumer Protection Directorate-General. 2002. Risk profile on the microbiological contamination of fruits and vegetables eaten raw, SCF/CS/FMH/SURF/Final, 29 April. Brussels (also available at http://europa.eu.int/comm/food/fs/sc/scf/out125_en.pdf).
FAO. 2002. World agriculture: towards 2015/2030. Summary report, pp. 11-20. Rome.
FAO/WHO. 2001. Hazard analysis and critical control point (HACCP) system and guidelines for its application, Annex to CAC/RCP 1-1969, Rev. 3 (1997). Food hygiene. Basic texts (second edition), Codex Alimentarius-Joint FAO/WHO Food Standards Programme, pp. 33-45. Rome (also available at http://www.fao.org/docrep/005/y1579e/y1579e00.htm).
Feng, P. 1997. A summary of background information and foodborne illness associated with the consumption of sprouts. Washington, DC, Centre for Food Safety and Applied Nutrition, Food and Drug Administration
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Madden, P. 1992. Microbial pathogens in fresh produce - The regulatory perspective. J. Food Protection, 55: 821-823.
Olsen, S.J., MacKinon, L.C., Goulding, J.S., Bean, N.H. & Slutsker, L. 2000. Surveillance for foodborne-disease outbreaks - United States, 1993-1997. MMWR, 17 March, 49 (SS01): 1-51 (also available at http://www.cdc.gov/mmwr/PDF/SS/SS4901.pdf).
Pollack, S.L. 2001. Consumer demand for fruit and vegetables: the U.S. example. Changing structure of global food consumption and trade. WRS-01-1. Washington, DC, United States Department of Agriculture.
Taormina, P.J., Beuchat, L.R. & Slutsker, R. 1999. Infections associated with eating seed sprouts: An international concern. Emerg. Infect. Dis., 5: 629-634.
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