Gollis University. Preservation post harvest technology in Fruit and Vegetable. A Thesis. Mukhtar Mohamed Hussein

Transcription

1 Gollis University Preservation post harvest technology in Fruit and Vegetable A Thesis By Mukhtar Mohamed Hussein FACULTY OF AGRICULTURE & NATURAL RESOURCE MANAGEMENT GOLLIS UNIVERSITY HARGIESA, SOMALILAND May,

2 Certificate This is to certify that the project titled Preservation post harvest technology in Fruit and Vegetable Is bona-fide work done by. Mukhtar Mohamed Hussein In compilation of the requirements for the bachelor of the agriculture and natural resource management (Mohamed Osman Bule) Advisor This thesis has been submitted with my approval as supervisor: Signature: Date: 2

3 Dedication I dedicated to my parents Shamis Elmi Buni, and Mohamed Hussein Tani 3

4 Acknowledgement First praise is to Allah who allowed me to write research made us possible to completion of this study. Secondly I would like to thanks my parents who brought me up and played an essential role in my education and Ahmed Sulieman Dhuhul for his support in every side. Also my supervisor Professor Mohamed Osman Bule, for his sacrifice to his precious time. I am Also thank to all my classmates especially Daaha Mohamed Abdi, who helped me during the research, Also I cannot forget our close friends who helped us during this research. I would like to suggest all our acknowledgements to everyone who helped us any kind of assistant during this hard work. 4

5 Table of Contents Dedication... 3 Acknowledgement... 4 Table of Contents... 5 Abstract... 7 Chapter One: Introduction STATUS OF POSTHARVEST HANDLING CAUSES OF POSTHARVEST LOSSES External Factors Internal Factors SCOPE AND STRATEGIES Raw Material Packing Stations Primary Processing Packaging Corrugated On Farm Storage Chapter Two: Literature Review Definitions THE BASICS OF POSTHARVEST TECHNOLOGY Processing and preserving methods Drying Processing using chemicals Preserves with sugar Preservation with salt Heat treatments Packing Practices and Packaging Materials COOLING PRACTICES STORAGE PRACTICES Chapter Three: Method and Materials Introduction Research design

6 3.3 Data collection instruments Data Analysis Chapter Four: Data Analysis On-farm causes of loss Causes of loss after harvest Damage in the marketing chain Production practices and Handling at farmers level Season of production and production system Problems faced during production and causes of postharvest losses Quality production, transportation, packaging and loss in percentage (general) Marketing of Horticultural crops at level of traders Selection criteria of fruits and vegetables during marketing Demand and supply Price determining factors Loss of commodities during transportation and storage Chapter Five: Summary and Conclusion Summary Conclusion Recommendation Reference

7 Abstract In a Somaliland reducing postharvest food losses is a major agricultural goal. For highly perishable commodities, such as tomatoes, squash, and peaches, as much as 30 percent of the harvested crop may be lost to postharvest diseases before it reaches the consumer. Investments made to save food after harvest is usually less costly for the grower and the consumer and less harmful to the environment than efforts to increase production. Even a partial reduction in postharvest losses can significantly reduce the overall cost of production and lessen our dependence on marginal land and other scarce resources. Many factors contribute to postharvest losses in fresh fruits and vegetables. These include environmental conditions such as heat or drought, mechanical damage during harvesting and handling, improper postharvest sanitation, and poor cooling and environmental control. Efforts to control these factors are often very successful in reducing the incidence of disease. For example, reducing mechanical damage during grading and packing greatly decreases the likelihood of postharvest disease because many disease-causing organisms (pathogens) must enter through wounds. Chemicals have been widely used to reduce the incidence of postharvest disease. 7

8 Chapter One: Introduction Food security, both in terms of availability and access to food, poses a challenge to rapidly growing populations, in environments of dwindling land and water resources. The horticultural sector has established its credibility for improving land use, and generating employment and nutritional security. Horticulture, which includes the production of fruits, vegetables, flowers, spices, medicinal and aromatic plants and plantation crops has emerged as a major economic activity in Asia and Pacific. For the most part, fruits and vegetables are not considered to be primary sources of carbohydrate, protein and fat. However, those with storage roots and tubers are rich in carbohydrate, particularly starch, in amounts comparable to the cereal crops, and can be used as staple foods. Leguminous vegetables supply as much as 14% protein, while dry seeds supply even more. The lipid content of most vegetables is less than 0.1%. Most fruits, vegetables and root crops are rich in minerals, carotene (Pro-vitamin A) and vitamin C, and are reasonably good sources of trace elements such as copper, manganese and zinc, which act as enzyme cofactors. The nutrient content of fruits and vegetables varies in accordance with the fruit or vegetable variety, cultural practices, stage of maturity, postharvest handling and storage conditions. Natural physiological and biochemical activity in fruits and vegetables results in compositional changes following harvest. Apart from their nutritive value, other constituents of fruits and vegetables which deserve attention include antioxidants, bioflavonoids, flavor compounds and dietary fibre. Often, the leafy portion of some important vegetables is discarded while the fleshy portion is consumed with little recognition for the fact that rich sources of nutrients such as calcium, iron, vitamin-c and carotene go to waste. Apart from the common and generally costly fruits, a large number of indigenous fruits, examples of which include Aonla and Baelfruit are rich sources of ascorbic acid (Vitamin-C) and riboflavin (Vitamin-B2). Some tropical fruits and vegetables are known to have therapeutic properties and are popularly used in traditional medicine in several countries of the region. 8

9 1.1 STATUS OF POSTHARVEST HANDLING Poor infrastructure for storage, processing and marketing in many countries of the region contributes to a high proportion of waste, which average between 10 and 40%. Major infrastructural limitations also continue to impose severe constraints to domestic distribution as well as to the export of horticultural produce. Considerable waste occurs owing to the fact that small farmers lack resources and are unable to market their produce and implement suitable postharvest handling practices. Spoilage of fresh produce is also accelerated by the hot and humid climate of the region. Postharvest management and processing of horticultural produce has assumed considerable significance in light of increasing demand for fruits and vegetables in the region. The World Food Conference convened in Rome in 1974, drew attention to the concept of postharvest food loss reduction as a significant means to increase food availability. The Special Action Program for Food Loss Prevention, of the Food and Agriculture Organization of the United Nations (FAO) initially focused on durable food grains, owing to their prominence in developing country diets. An Expert Consultation on Food Loss Prevention in Perishable Crops, mainly covering fruit and vegetables was held in Rome in Although India is a major producer of horticultural crops, many Indians are unable to obtain their daily requirement of fruits and vegetables and the Human Development Index (HDI) is very low. Considerable quantities of fruits and vegetables produced in India go to waste owing to improper postharvest operations and the lack of processing. This results in a considerable gap between gross food production and net availability. It should be noted that the production of fruits and vegetables is of significance only when they reach the consumer in good condition and at a reasonable price. The concept of placing exclusive emphasis on increased production of fruits and vegetables is self-defeating. It is important to see how much of the produce goes through marketing channels and finally reaches the consumer. It is known that food loss reduction is normally less costly than equivalent increases in food production. Reduction of postharvest losses is essential in increasing food availability from existing production. The success of production lies in the proper distribution of produce and its subsequent utilization by the consumer with zero waste in the process i.e., 100% utilization of production in one form or another should be the motto. Opportunities exist in both domestic and international markets for fresh and processed fruits and vegetables. 9

10 1.2 CAUSES OF POSTHARVEST LOSSES Postharvest losses are caused by both external and internal factors External Factors Mechanical Injury Fresh fruits and vegetables are highly susceptible to mechanical injury owing to their tender texture and high moisture content. Poor handling, unsuitable packaging and improper packing during transportation are the cause of bruising, cutting, breaking, impact wounding, and other forms of injury in fresh fruits and vegetables. Parasitic Diseases The invasion of fruits and vegetables by fungi, bacteria, insects and other organisms, is a major cause of postharvest losses in fruits and vegetables. Microorganisms readily attack fresh produce and spread rapidly, owing to the lack of natural defense mechanisms in the tissues of fresh produce, and the abundance of nutrients and moisture which supports their growth. Control of postharvest decay is increasingly becoming a difficult task, since the number of pesticides available is rapidly declining as consumer concern for food safety is increasing Internal Factors Physiological Deterioration Fruit and vegetable tissues are still alive after harvest, and continue their physiological activity. Physiological disorders occur as a result of mineral deficiency, low or high temperature injury, or undesirable environmental conditions, such as high humidity. Physiological deterioration can also occur spontaneously owing 1.3 SCOPE AND STRATEGIES The unnecessary waste of valuable commodities can be checked by processing into value added products. Considerable scope exists for both domestic and export trade in fruits and vegetables in India. This will, however, only be achieved with improved distribution systems and processing of these highly perishable horticultural commodities. 10

11 Raw Material No matter how perfect postharvest operations are, good returns cannot be obtained from poor quality raw materials. The selection of suitable varieties is, therefore, essential. Linking production to postharvest operations is essential to optimizing results. Pre-harvest parameters such as selection of proper planting material, crop management, and disease and pest control must be geared toward producing high quality produce. Once the crop is ready for harvest, attention must be paid to the harvesting technique/procedure. Poor harvesting practices can lead to irreparable damage to horticultural produce. It is therefore necessary to standardize maturity indices and harvesting techniques for each and every fruit and vegetable in order to minimize damage at the time of harvest. Packing Stations There is an absolute lack of the concept of packing house establishments in India. Fruits and vegetables are generally packed in the field without any pretreatment. Some are even transported without any packaging. In developed countries on the other hand, fruits and vegetables are generally selected, cut, placed in bulk containers and transported to packing stations where they are trimmed, sorted, graded, packed in cartons or crates and cooled. They are temporarily placed in cool storage for subsequent loading or are loaded directly onto refrigerated vehicles, and transported to market. A number of important operations are also carried out at packing stations. These include SO2 fumigation, fungicidal dipping, surface coating with wax, degreening of citrus, ripening and conditioning, vapor heat treatment etc. Due to the lack of proper packaging systems in India, large volumes of the inedible portions of vegetables such as cauliflower, peas etc. are transported to wholesale markets from the field. They are discarded to various degrees and large quantities of biomass which could be used as value added products are wasted. Removal of these inedible vegetable portions prior to marketing would reduce both transportation costs and environmental pollution. These inedible vegetable parts ultimately undergo decomposition, cause sanitation problems and produce gases which are detrimental to the environment. Farmer s cooperatives and other agencies should, therefore, be encouraged to establish packing stations at nodal points to augment the marketing of fresh horticultural produce. 11

12 Primary Processing Unlike durable crops such as cereals, pulses and oilseeds, fresh fruits and vegetables are highly perishable, and must be marketed immediately after harvesting without primary processing. Fruit and vegetables generate large quantities of valuable waste that ends up as garbage. However, if they are gainfully utilized at the proper time they can become value added products. Vegetables such as cauliflower, peas, leafy vegetables, etc. can be minimally processed at packing stations immediately after harvesting, through the removal of inedible parts, following which they can be marketed in metro city markets in unit packs. Between 10 and 60% of the fresh fruits and vegetables marketed and purchased by consumers in India are rejected as inedible. In villages or small towns the inedible portions of fruits and vegetables are either fed to animals or are discarded as garbage by consumers in metro cities. Primary processing of food crops other than horticultural crops has its origin from the dawn of civilization. It was a necessary step to the consumption of foods such as rice, wheat, oilseeds, etc. Processing not only renders these commodities edible, but also adds value to them. Value-addition to horticultural crops was never considered essential, owing to the fact that many of these fruits and vegetables, e.g., tomato, melon, cucumber, carrot, etc. could be directly consumed after harvesting. Today, there is considerable interest in processing to add value, as well as to reduce losses in fruits and vegetables. Packaging Packaging is an integral element in the marketing of fresh horticultural produce. It provides an essential link between the producer and the consumer. Owing to its favorable properties, wood has remained the main packaging material for fruits and vegetables. Timber conservation is, however, critical in order to maintain an ecological balance, and there is an urgency to identify substitutes for the use of timber in an effort to protect forest resources in many developing countries. Packaging has been identified as one of the most important areas where substitution of wood is not only possible but also obviously desirable. Considerable work has been done by different agencies in introducing alternative types of packaging. Corrugated fibre board (CFB) containers consume one third of the wood required for producing timber boxes of the same size. CFB boxes can also be fabricated from kraft paper produced from bamboo, long grasses and many other types of agricultural residues like bagasse, paddy, 12

13 cotton stalk, jute stick, wheat straw and recycled paper and cardboard. Packaging produced from timber is often used as a source of firewood, owing to the severe shortage of fuel wood in India. CFB cartons on the other hand are recycled as pulp or paper. Thus switching over from wood to CFB boxes for the packaging of horticultural produce is a very practicable and environmentally friendly option. Increased use of corrugated cartons for local distribution of produce could be accomplished with improvement in the quality of boxes produced in India. The ventilated CFB box which contains ventilated partitions, and which was developed at the IARI was found to be ideal for the packaging and transportation of fruits, owing to the comparably minimal level of bruising observed in these boxes. Cushioning materials used in the packaging of fruits and vegetables in wooden boxes include dry grass, paddy straw, leaves, sawdust, paper shreds etc., all of which end up as garbage and add to environmental pollution in cities. Moulded trays or cardboard partitions used in CFB boxes are, however, easily recycled. On Farm Storage On farm storage is required in remote and inaccessible areas of India, to reduce losses in highly perishable fresh horticultural produce. The high cost and high energy requirements of refrigeration, and the difficulty of installing and running refrigerated facilities in remote areas of India, precludes the use of refrigerated storage in many parts of India. Low-cost, low-energy, environmentally friendly cool chambers made from locally available materials, and which utilize the principles of evaporative cooling, were therefore developed in response to this problem. These cool chambers are able to maintain temperatures at 10 15oC below ambient, as well as at a relative humidity of 90%, depending on the season. Fruits and vegetables are stored in plastic crates within the chamber. The shelf life of the fruit and vegetables maintained in the cool chamber was reported to be increased from 3 days at room temperature, to 90 days. 13

14 Chapter Two: Literature Review 2.1 Definitions Accreditation the evaluation and formal recognition of a program, service, etc., by a competent and recognized authority. Action plan actions or recommendations to be accomplished to develop, improve or correct a program addressed to ensure the quality and safety of a product. Agricultural inputs all materials used in primary production of fresh fruits and vegetables (for example, seeds, fertilizers, water, agro- chemicals). Certification a procedure in which a third party gives a written guarantee that a product, process or service conforms to a standard. Certification can be seen as a way by which the actors in the chain (producers traders consumers) relate to each other to ensure the safety and quality of a product. Clean water water that does not impair food safety in the way in which it is used. Cleaning the removal of soil, food residue, dirt, grease or other objectionable matter. Code of practice voluntary document, containing general recommendations that allow its adoption by the sector to which it is addressed. It gives general recommendations on practices and operations to implement the established objectives. Cold chain maintaining suitable refrigeration temperatures throughout the handling chain of a product, to ensure its quality and safety. Composting a controlled process in which aerobic and anaerobic micro-organisms digest organic materials. Contaminant means any substance not intentionally added to food, which is present in such food as a result of the production (including operations carried out in crop husbandry, animal husbandry and veterinary medicine),manufacture, processing, preparation, treatment, packing, packaging, transport or holding of such food or as a result of environmental contamination. The term does not include insect fragments, rodent hairs and other extraneous matter. 14

15 Contamination the introduction or occurrence of a contaminant in food or food environment. Disinfection the reduction, by means of chemical agents and/or physical methods, of the number of micro-organisms in the environment, to a level that does not compromise food safety or suitability. Food-borne disease (FBD) any symptom or syndrome resulting from a disease transmitted to human beings by contaminated foods. Food hygiene comprises conditions and measures necessary for the production, processing, storage and distribution of food designed to ensure a safe, sound, wholesome product fit for human consumption. HACCP a system which identifies, evaluates and controls hazards that are significant for food safety. Food safety assurance that food will not cause harm to the consumer when it is prepared and/or eaten according to its intended use. Food suitability assurance that food is acceptable for human consumption according to its intended use. Good agricultural practices practices of primary production improving on conventional production and handling methods, to ensure product safety, reducing the negative impact of production systems on the environment, fauna, flora and workers health. Good manufacturing practices post-harvest practices to prevent and control product safety hazards with reduced effects on the environment and on workers health. Hazard a biological, chemical or physical agent in, or condition of, food with the potential to cause an adverse health effect. Hazard analysis the process of collecting and evaluating information on hazards and conditions leading to their presence to decide which are significant for food safety and therefore should be addressed in the HACCP plan. Micro-organisms include yeasts, fungi, bacteria and viruses. 15

16 Pathogen any micro-organism causing human diseases. Potable water drinking water complying with the World Health Organization s (WHO) quality regulations for potable water. Primary production those steps in the food chain up to and including, for example, harvesting, slaughter, milking and fishing. Quality enhancement in this Manual, quality enhancement embraces activities relating to product handling to enhance its quality attributes using, for example, post-harvest technologies. Quality enhancement is a differentiating strategy to open market opportunities. Post-harvest only maintains and enhances primary quality, it does not make it. Risk a function of the probability of an adverse health effect and the severity of that effect, consequential to a hazard(s) in food. Risk analysis a process consisting of three components: risk assessment, risk management and risk communication. Standardized Sanitary Operation Procedures (SSOPs) fully recorded and detailed description of cleaning and disinfection procedures to ensure their correct implementation. Traceability/product tracing the ability to follow the movement of a food through specified stages (s) of production, processing and distribution. Preservation Process means protections or barrier method to stop spoilage of fruit and vegetables 16

17 2.2 THE BASICS OF POSTHARVEST TECHNOLOGY 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 (both physical and in market value) 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 simple practices have successfully been used to reduce losses and maintain produce quality of horticultural crops in various parts of the world for many years. 17

18 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 are often followed. Harvesting and preparation for market Curing root, tuber and bulb crops Packinghouse operations Packing and packaging materials Decay and insect control Temperature and relative humidity control Storage of horticultural crops Transportation of horticultural crops Handling at destination PACKING AND PACKAGING PRACTICES A recent study by WFLO (funded by the Bill & Melinda Gates Foundation) reported on many issues related to the use of poor quality packages in Africa and India. The scientists field tested a variety of improved packages, including plastic crates, liners for rough containers, and smaller sized sacks, and found them all to be simple to use and cost effective. This container is too large to protect produce. The tomatoes at the bottom are squashed, and the handler is overloaded with a much too heavy container. 18

19 2.3 Processing and preserving methods To process and preserve fresh produce successfully, the spoilage agents must be destroyed without ruining the nutritional value or palatability of the produce itself. Unfortunately, fruit, vegetables and root crops are the only natural source of the essential vitamin C in our food. This vitamin is easily destroyed, especially where processing makes use of heat. In order to retain the maximum amount of vitamin C in processed food, it: should be used when freshly harvested; must not be subjected to long soaking or washing; must be processed immediately after preparation; should not be treated in copper, iron or chipped pans. The best methods for small-scale processing are: drying, chemical preservation and heat processing Drying. All living materials require water for survival. Fresh produce contains up to 95 percent water and thus is sufficiently moist to support both enzyme activity and growth of micro-organisms. The aim in drying is to reduce the water content of the produce to a level insufficient for enzyme activity or the growth of micro-organisms. The critical level is about percent moisture, depending on the commodity. If too much water is removed, the product becomes brittle and is easily shattered. Produce can be dried by using solar or artificial heat. Solar (sun) drying is cheap but is not so easily controlled as dehydration by more sophisticated means. In some countries, heat from burning agricultural waste is used for drying, as in copra driers, which have also been used for drying root crops. Drying by direct exposure to the sun has a number of disadvantages: Exposure of produce to dust and atmospheric contamination 19

20 Interference from animals and humans Insect infestation No control of conditions. Recently much research has gone into the design of solar driers for fresh produce in order to overcome these problems. Solar driers can be: direct exposure driers, in which the prepared produce is exposed to the sun in a ventilated cabinet with transparent sides and cover, on an insulated, heat-absorbing base; there is little control of temperature or air flow; indirect exposure driers, in which an inclined, insulated heat trap directs a flow of sunheated air up a tower where produce is exposed on mesh trays; the air flow and temperature con be controlled by louvres at the air inlet and outlet; a combination of direct and indirect drying is employed when the walls of the tower of an indirect drier are covered with transparent material so that there is some direct exposure of the drying material to the sun's heat. The rate of loss of vitamin C from the produce is reduced when the indirect solar drying method is used. Drying should be as rapid as possible in order to maintain quality and minimize vitamin loss. The rate of drying depends on: the exposure of a large surface area of the produce, which speeds drying; most produce should be cut into strips not more than 5 mm thick; the temperature should be high enough (50-70 degrees Celsius) to give rapid moisture removal; temperatures over 70 degrees cause discoloration of the product; the warm air current must be dry; if it is humid, it cannot absorb moisture from the drying product; special treatments may be given to certain types of produce before drying; for example: 20

21 1. Fruit and vegetables may be treated with sulphur dioxide before drying in order to prevent enzymatic browning; it also slows breakdown of vitamin C and kills some micro-organisms; 2. Most vegetables except onions and garlic are blanched by dipping them in hot water for a few minutes before drying; this stops the action of enzymes which may not be killed by the sun-drying process; 3. Green vegetables retain their colour better during drying if about 0.25 percent of bicarbonate of soda is added to the blanching water, but this will speed up the loss of vitamin C; 4. Dried cassava forms an important part of the staple diet in parts of Africa and Latin America; the dried product may be in the form of chips, granules or flour; in some areas the grated cassava root is fermented for a short time before being dried by artificial heat or sunlight; 5. Dried vegetable products are subject to severe insect infestation, and some may be affected by exposure to light during storage; dried produce must be stored in a very dry atmosphere, in insect-proof containers and away from light. 2.4 Processing using chemicals. Chemicals used in processing include sugar, salt, vinegar and chemical preservatives such as sodium meta-bisulphite. The principal products are: Preserves with sugar. This is based on using a high concentration of sugar with fruit pulp or juice to create a product in which it is difficult for moulds and yeasts to grow. It includes: Jams and jellies. In these products acidified fruit pulp is boiled with sugar until the cell wall pectins of the fruit form a gel. The final product should contain at least 60 percent sugar. The hot preserve is sealed in sterilized jars to prevent contamination during storage. 21

22 Fruit cheeses. Pulped fruit is sieved and mixed with an equal weight of sugar. The mixture is heated to remove most of the water. It is then spread on trays to cool and dry; then it can be cut into cubes and stored under very dry conditions. Fruit drink concentrates. The juice is extracted from heated fruit pulp and made into a syrup with a high sugar concentration. The squash or syrup is put into sterilized bottles, which are heated in a bath at 88 degrees Celsius (simmering) for 20 minutes. The bottles are closed with sterile caps for storage. Drinks are prepared by diluting the concentrate with water. Pickled vegetables. Young fresh vegetables of many types as well as some fruits can be preserved by pickling in vinegar. The prepared vegetables or fruit are first soaked for a few days in a strong salt solution (brine) and then packed into jars which are then filled with cold vinegar. The vinegar is usually flavoured by steeping the desired spices in it for one or two months. The jars should be closed with plastic-lined covers Preservation with salt. This method is usually used for preserving green beans. Young green beans and salt are placed in alternate layers in large glass or earthenware jars, the top layer being of salt. The jars are closed with moisture-proof covers and then they are stored on stands. Fermented products. In several countries vegetables are subjected to lactic acid fermentation in brine, such as sauerkraut in Germany, made from shredded cabbage, and takuwan in Korea, using radishes. In the Pacific islands, a fermented product is made by burying peeled starchy produce in pits lined with Heliconia or banana leaves. The product, known as masi or ma, is mostly made from breadfruit, but green bananas, cassava roots or taro may also be used. 2.5 Heat treatments. For many years fruit and vegetables have been preserved by heat, using canning or bottling methods. The object is to kill the enzymes and micro-organisms by heating the produce in liquid in cans or jars. The containers are then sealed while still hot to prevent contamination of the sterilized contents. Although moist heat inactivates enzymes and kills most micro-organisms, 22

23 some bacteria, such as Clostridium and Staphylococcus are heat-resistant and are capable of growing and producing poisons in canned or bottled foods. Clostridium produces a toxin which causes botulism, a fatal food poison. Acid foods, such as fruit, inhibit the growth of Clostridium and prevent the formation of the poison. Non-acid foods such as peas and beans and almost all vegetables can be preserved only by heat at the high temperatures achieved in steam-pressure vessels. For this reason, heat-processing methods are not recommended for processing any vegetables under small-scale local conditions. 2.6 Packing Practices and Packaging Materials Throughout the entire handling system, packaging can be both an aid and a hindrance to obtaining maximum storage life and quality. Packages need to be vented yet be sturdy enough to prevent collapse. If produce is packed for ease of handling, waxed cartons, wooden crates or rigid plastic containers are preferable to bags or open baskets, since bags and baskets provide no protection to the produce when stacked. Sometimes locally constructed containers can be strengthened or lined to provide added protection to produce. Waxed cartons, wooden crates and plastic containers, while more expensive, are cost effective when used for the domestic market. These containers are reusable and can stand up well to the high relative humidity found in the storage environment. Adding a simple cardboard liner to a crate will make it less likely to cause abrasion to produce. Containers should not be filled either too loosely or too tightly for best results. Loose products may vibrate against others and cause bruising, while over-packing results in compression bruising. Shredded newspaper is inexpensive and a lightweight filler for shipping containers (if the ink used for newspaper print is non-toxic). 23

24 For small-scale handlers interested in constructing their own cartons from corrugated fiberboard, Broustead and New (1986) provide detailed information. Many types of agricultural fibers are suitable for paper making and handlers may find it economically sensible to include these operations in their postharvest system. Corrugated fiberboard is manufactured in four flute types - type B (1/8 inch in height, 47 to 53 flutes per inch; with a basis weight of 26 lb per 1,000 ft2) is the most commonly used for handling perishables. Whenever packages are handled in a high humidity environment, much of their strength is lost. Collapsed packages provide little or no protection, requiring the commodity inside to support all of the weight of the overhead load. Packing is meant to protect the commodity by immobilizing and cushioning it, but temperature management can be made more difficult if packing materials block ventilation holes. Packing materials can act as vapor barriers and can help maintain higher relative humidity within the package. In addition to protection, packaging allows quick handling throughout distribution and marketing and can minimize impacts of rough handling. Produce can be hand-packed to create an attractive pack, often using a fixed count of uniformly sized units. Packaging materials such as trays, cups, wraps, liners and pads may be added to help immobilize the produce. Simple mechanical packing systems often use the volume-fill method or tight-fill method, in which sorted produce is delivered into boxes, then vibration settled. Most volume-fillers are designed to use weight as an estimate of volume, and final adjustments are done by hand. Ethylene absorber sachets placed into containers with ethylene sensitive produce can reduce the rate of ripening of fruits, de-greening of vegetables or floral wilting. Sachets can be purchased from internet based companies. Some illustrations of improved practices: 24

25 2.7 COOLING PRACTICES Temperature and Relative Humidity Control Throughout the period between harvest and consumption, temperature control has been found to be the most important factor in maintaining product quality. Fruits, vegetables and cut flowers are living, respiring tissues separated from their parent plant. Keeping products at their lowest safe temperature (0 C or 32 F for temperate crops or C or F for chilling sensitive crops) will increase storage life by lowering respiration rate, decreasing sensitivity to ethylene gas and reducing water loss. Reducing the rate of water loss slows the rate of shriveling and wilting, causes of serious postharvest losses. Keeping products too cool can also be a serious problem. It is important to avoid chilling injury, since symptoms include failure to ripen (bananas and tomatoes), development of pits or sunken areas (oranges, melons and cucumbers), brown discoloration (avocados, cherimoyas, eggplant), 25

26 increased susceptibility to decay (cucumbers and beans), and development of off-flavors (tomatoes) (Shewfelt, 1990). Cooling involves heat transfer from produce to a cooling medium such as a source of refrigeration. Heat transfer processes include conduction, convection, radiation and evaporation. If a ready supply of electricity is available, mechanical refrigeration systems provide the most reliable source of cold. Methods include room cooling, forced-air cooling and evaporative cooling. A variety of portable forced-air coolers have been designed for use by small-scale growers and handlers (Talbot and Fletcher, 1993; Rij et al, 1979; Parsons and Kasmire, 1974). However, a variety of simple methods exist for cooling produce where electricity is unavailable or too expensive. Some examples of alternative systems (from Thompson in Kader, 1992) include night air ventilation, radiant cooling, evaporative cooling, the use of ice and underground (root cellars, field clamps, caves) or high altitude storage. Ice can be manufactured using simple solar cooling systems, where flat plate solar collectors are used to generate power to make ice, which is then used to cool produce (Umar, 1998). Ice can be used either directly as package ice, to cool water for use in a hydro-cooler, or as an ice bank for a small forced air or room cooling system. Several simple practices are useful for cooling and enhancing storage system efficiency wherever they are used, and especially in developing countries, where energy availability may be limited and any savings may be critical. Shade should be provided over harvested produce, packing areas, for buildings used for cooling and storage and for transport vehicles. Using shade wherever possible will help to reduce the temperatures of incoming produce and will reduce subsequent cooling costs. Trees are a fine source of shade and can reduce ambient temperatures around packinghouses and storage areas. Light colors on buildings will reflect light (and heat) and reduce heat load. Sometimes spending money will save money, as when purchasing lighting equipment. High pressure sodium lights produce less heat and use less energy than incandescent bulbs. Another aspect to consider when handling fruits and vegetables is the relative humidity of the storage environment. Loss of water from produce is often associated with a loss of quality, as visual changes such as wilting or shriveling and textural changes can take place. If using 26

27 mechanical refrigeration for cooling, the larger the area of the refrigerator coils, the higher the relative humidity in the cold room will remain. It pays however, to remember that water loss may not always be undesirable, for example if produce is destined for dehydration or canning. For fresh market produce, any method of increasing the relative humidity of the storage environment (or decreasing the vapor pressure deficit (VPD) between the commodity and its environment) will slow the rate of water loss. The best method of increasing relative humidity is to reduce temperature. Another method is to add moisture to the air around the commodity as mists, sprays, or, at last resort, by wetting the store room floor. Another way is to use vapor barriers such as waxes, polyethylene liners in boxes, coated boxes or a variety of inexpensive and recyclable packaging materials. Any added packaging materials will increase the difficulty of efficient cooling, so vented liners (about 5 percent of the total area of the liner) are recommended. The liner vents must line up with the package vents to facilitate cooling of the produce inside. Vented liners will decrease VPD without seriously interfering with oxygen, carbon dioxide and ethylene movement. 2.8 STORAGE PRACTICES Storage of horticultural crops If produce is to be stored, it is important to begin with a high quality product. The lot of produce must not contain damaged or diseased units, and containers must be well ventilated and strong enough to withstand stacking. In general proper storage practices include temperature control, relative humidity control, air circulation and maintenance of space between containers for adequate ventilation, and avoiding incompatible product mixes. Commodities stored together should be capable of tolerating the same temperature, relative humidity and level of ethylene in the storage environment. High ethylene producers (such as ripe bananas, apples, cantaloupe) can stimulate physiological changes in ethylene sensitive commodities (such as lettuce, cucumbers, carrots, potatoes, sweet potatoes) leading to often undesirable color, flavor and texture changes. 27

28 Temperature management during storage can be aided by constructing square rather than rectangular buildings. Rectangular buildings have more wall area per square feet of storage space, so more heat is conducted across the walls, making them more expensive to cool. Temperature management can also be aided by shading buildings, painting storehouses white or silver to help reflect the sun's rays, or by using sprinkler systems on the roof of a building for evaporative cooling. The United Nations' Food and Agriculture Organization (FAO) recommends the use of ferrocement for the construction of storage structures in tropical regions, with thick walls to provide insulation. Facilities located at higher altitudes can be effective, since air temperature decreases as altitude increases. Increased altitude therefore can make evaporative cooling, night cooling and radiant cooling more feasible. Underground storage for citrus crops is common in Southern China, while in Northwest China, apples are stored in caves (Liu, 1988). This system was widely used in the U.S. during the early pert of this century. Certain commodities, such as onions and garlic, store better in lower relative humidity environments. Curing these crops and allowing the external layers of tissue to dry out prior to handling and storage helps to protect them from further water loss. The air composition in the storage environment can be manipulated by increasing or decreasing the rate of ventilation (introduction of fresh air) or by using gas absorbers such as potassium permanganate or activated charcoal. Large-scale controlled or modified atmosphere storage requires complex technology and management skills, however, some simple methods are available for handling small volumes of produce. 28

29 Chapter Three: Method and Materials 3.1 Introduction This chapter outlines the detailed methodology that will use in the collection of data. It highlights the research design, study population, sample size and selection, sampling methods and procedure, data collection methods and data collection instruments, target population, data analysis and presentation. 3.2 Research design Research design is a plan for carrying out a research project. The study will use cross sectional study design to gather information from similar respondents. The design is suitable because the study will carry out at a particular point in time and involved the same respondents. The study results to obtain will generalize to a larger population in growers. Both qualitative and quantitative approaches will use to gather and analyze information in the study. The research finding is appropriate because it will have simple design since the researcher will direct contact with the study population from which selected samples to get the required information of the study. The researcher will use both open ended and close-ended questionnaires to the selected samples. 3.3 Data collection instruments Primary data will collect through both open and close-ended questionnaires, which will be self administered to collect data from beekeepers and bee managers. Questionnaires will consider the best methods that can be easy and quick to fill and they protect the identity of the respondents. Observation will employ while in the field to check some of the aspects that show environmental aspects that can be influence some factors about bee sustainability in our country. This include like infrastructure in these firms; for instance equipment, employee, sanitary facilities etc and the number of bee houses The available secondary data will also be a source of reference information. 29

30 3.4 Data Analysis Data will analyze using two principle methods in accordance with the approaches in the research that is quantitative and qualitative analyses. For quantitative data, a scale will develop and responses will code in accordance with the like scale. All the data will enter in excel sheet for analysis. The analysis will make descriptively in terms of frequencies and percentages and will present in consistent tables. For qualitative data from structured questionnaires and in depth interview guide, which is not standardized, sub matter s relating data to the matter will develop and all the data fit in even as employing word for word reports. 30

31 Chapter Four: Data Analysis 4.1 On-farm causes of loss There are numerous factors affecting post-harvest losses, from the soil in which the crop is grown to the handling of produce when it reaches the shop. Pre-harvest production practices may seriously affect post-harvest returns. Plants need a continuous supply of water for photosynthesis and transpiration. Damage can be caused by too much rain or irrigation, which can lead to decay; by too little water; and by irregular water supply, which can, for example, lead to growth cracks. Lack of plant food can affect the quality of fresh produce, causing stunted growth or discoloration of leaves, abnormal ripening and a range of other factors. Too much fertilizer can harm the development and post-harvest condition of produce. Good crop husbandry is important for reducing losses. Weeds compete with crops for nutrients and soil moisture. Decaying plant residues in the field are also a major loss factor. 4.2 Causes of loss after harvest Fruits and vegetables are living parts of plant and contain 65 to 95 percent water. When food and water reserves are exhausted, produce dies and decays. Anything that increases the rate at which a product s food and water reserves are used up increases the likelihood of losses. Increases in normal physiological changes can be caused by high temperature, low atmospheric humidity and physical injury. Such injury often results from careless handling, causing internal bruising, splitting and skin breaks, thus rapidly increasing water loss. Respiration is a continuing process in a plant and cannot be stopped without damage to the growing plant or harvested produce. It uses stored starch or sugar and stops when reserves of these are exhausted, leading to ageing. Respiration depends on a good air supply. When the air supply is restricted fermentation instead of respiration can occur. Poor ventilation of produce also leads to the accumulation of carbon dioxide. When the concentration of carbon dioxide increases it will quickly ruin produce. Fresh produce continues to lose water after harvest. Water loss causes shrinkage and loss of weight. The rate at which water is lost varies according to the product. Leafy vegetables lose water quickly because they have a thin skin with many pores. Potatoes, on the other hand, have a thick skin with few pores. But whatever the product, to extend shelf or storage life the rate of water loss must be minimal. The most significant factor is the ratio of the 31