Chapter 5

The Quality in Fruits and Vegetables

5.1 What does the consumer demand?

Many publications speak generically of "consumer" as if a single type existed or as if his/her likes and preferences were perfectly defined. On the contrary, consumption profiles are specific for each country or even region and they vary with sex, age, and educational and socioeconomic level. However, there are universal behavior patterns, therefore, for the purpose of this publication we will only refer to those characteristics and demands that are common worldwide and that may be useful to understand the average consumer.

In the first place, there is a world tendency towards a greater consumption of fruits and vegetables due to a growing concern for a more balanced diet, with a lower proportion of carbohydrates, fats and oils and with a higher proportion of dietary fiber, vitamins, and minerals.

Another aspect that deserves attention is the tendency towards simplification in the task of preparing daily meals. In the United States, until the 60s, the preparation of lunch or dinner required about 2 hours and was planned in advance. Nowadays, meals are prepared in less than one hour and the menu to be served at dinner begins to be defined after 4 p.m. (Cook, 1998). The expanding incorporation of processed fruits and vegetables and other ready-made foods are partly responsible for this reduction in the time dedicated to cooking. Probably, the most significant fact that encourages this tendency is woman's increasing incorporation in full-time work that reduces her time to buy and to prepare foods but giving her more capacity to spend money.

Also influencing the consumption patterns is the increasing market segmentation through the expansion in shapes, colours, flavors, ways of preparation, and/or packaging in which a product is presented. Among others, tomatoes are an example of it, since today they can be purchased in at least 4 different types: conventional or "beef tomato", "extended shelf life", "cherry", and processing types sold fresh, all of them in different sizes, packages and in some cases, colour. There is also an increasing supply of exotic or non-conventional fruits and vegetables, which together with the previous point, notably expands the purchase options. For example, in 1981, in a well-supplied supermarket of the USA, there were 133 options of different fruits and vegetables, but they increased to 282 in 1993 and to 340 in 1995 (Cook, 1997). Without reaching these levels, the same tendency is observed in the different countries of Latin America and the Caribbean.

Lastly, there is a growing demand for higher quality, external as well as internal quality. External aspects (presentation, appearance, uniformity, ripeness, and freshness) are the main components in the decision to purchase, which is usually taken when the consumer sees the product exhibited at the sales point (Figure 63). This is particularly important in the self-service systems where the product must "self-sell" and if it is not chosen, represents a loss for the retailer. Internal quality (flavor, aroma, texture, nutritional value, and absence of biotic and non-biotic contaminants) is linked to aspects not generally perceived externally, but are equally important to many consumers.

To summarize the previous paragraphs we can say that within a general tendency towards greater consumption and variety, the consumer demands quality in terms of appearance, freshness, presentation as well as nutritional value and safety.

5.2 Definition of quality

The word "quality" comes from the Latin qualitas that means attribute, property or basic nature of an object. However, nowadays it can be defined as the "degree of excellence or superiority" (Kader, et al., 1985). Accepting this definition, we can say that a product is of better quality when it is superior in one or several attributes that are objectively or subjectively valued.

In terms of the service or satisfaction that it produces to consumers, we could also define it as the "degree of fulfillment of a number of conditions that determine its acceptance by the consumer". Here, a subjective aspect is introduced, since different consumers will judge the same product according to their personal preferences.

The destination or use can also determine different criteria for judging quality within the same crop. For example, the tomato for fresh consumption is valued essentially by its uniformity, ripeness, and absence of defects, while colour, viscosity, and industrial yield as raw material define the quality for ketchup tomatoes. It is common to use additional words to define the quality to the specific use, such as "industrial quality", "nutritional quality", "export quality", "edible quality", etc.

Figure 63: Percentage of answers evaluating these visible aspects as extremely or very important (Reproduced from Tronstad, 1995).

5.3 Perception of quality

Quality is a complex perception of many attributes that are simultaneously evaluated by the consumer either objective or subjectively (Figure 64). The brain processes the information received by sight, smell, and touch and instantly compares or associates it with past experiences or with textures, aromas, and flavours stored in its memory. For example, just by looking at the colour, the consumer knows that a fruit is unripe and that it does not have good flavor, texture or aroma. If colour is not enough to evaluate ripeness, he/she uses the hands to judge firmness or other perceptible characteristics. The aroma is a less used parameter except in those cases where it is directly associated to ripeness like in melon or pineapple. This comparative process does not take place when the consumer faces, for the first time, an exotic fruit whose characteristics are unknown.

The final evaluation is the perception of the flavor, aroma, and texture that takes place when the product is consumed and when sensations perceived at the moment of purchase are confirmed. If satisfaction is the result, loyalty is generated. For example, if you discover that I prefer red apples to green ones, I will continue consuming red apples. It is possible to generate loyalty to commercial brands, presentation forms, packaging, sales places, etc.

Figure 64: Consumer perception of quality.

Fruits and vegetables are consumed mainly for their nutritive value as well as by the variety of shapes, colours, and flavors that make them attractive for food preparation. When they are consumed raw or with very little preparation, the consumer's main concern is that they must be free of biotic or non-biotic contaminants that may affect health.

5.3.1 Components of quality

5.3.1.1 Appearance

Appearance is the first impression that the consumer receives and the most important component of the acceptance and eventually of the purchase decision. Different studies indicate that almost 40% of the consumers decide what to buy inside the supermarket. Shape is one of the subcomponents more easily perceived, although in general, it is not a decisive aspect of quality, except in case of deformations or morphological defects. In some cases, shape is a ripeness index and therefore an indication of flavor. This is the case of the "full cheek" in mango or the "finger" angularity in bananas.

In those species where the inflorescence is the marketable organ such as broccoli or cauliflower or those that form "heads" like lettuce, cabbage, endive, etc. the compactness is the most relevant feature. In general, it is not associated to their organoleptic characteristics but rather is an indicator of the degree of development at harvest, since open inflorescences indicate that they were picked too late while non-compact "heads" are the consequence of a premature harvest. To a certain extent, it is also an indicator of freshness since compactness decreases with dehydration.

Uniformity is a concept applied to all the components of quality (size, form, colour, ripeness, compactness, etc.). For the consumer it is a relevant feature that indicates that someone that knows the product has already selected and separated it into categories based on the official standards of quality. It is so important that making products uniform is the main activity in preparation for the market.

In many cases, internal or external defects do not affect product excellence, but the consumer rejects them since the absence of defects is one of the main components of appearance and therefore, of the primary decision to purchase. Different causes during growth (climate, irrigation, soil, variety, fertilization, etc.) can lead to morphological or physiological defects. Some examples of the first ones are "doubles" in cherry, root ramifications in carrots, "catface" tomatoes, "knobby" tubers and "hollow heart" in potatoes, etc. Tipburn on leafy vegetables and black heart in celery due to calcium deficiencies as well as the internal rots in various species due to boron deficiencies are examples of physiological defects. More serious are those physical or physiological defects that originate during or after preparation for the fresh market and that show up at retail or consumer's level. Within the first ones we have the mechanical damages, bruises or wounds that take place during the handling of the product (Chapter 1) and that are the entrance doors to most pathogens causing postharvest rots. Chilling injury, ethylene effects as well as sprouting and rooting, are physiological responses to inadequate storage conditions.

Freshness and ripeness are part of the appearance and they have components of their own. They are also indicative of the expected flavor and aroma when products are consumed. "Freshness" is the condition of being fresh or as close to harvest as possible. It is used in vegetables where harvest is the point of maximum organoleptic quality characterized by the greatest turgidity, colour, flavor, and crispness. "Ripeness" is a concept used in fruits that also refers to the point of maximum eatable quality but that in many cases is reached at the level of sales point or of consumption since, in most commercial operations, fruits are harvested slightly immature. For example, fruits stored in controlled atmospheres reach their eatable quality after leaving the store room, several months after harvest.

Within the parameters for defining freshness and ripeness, colour, both intensity and uniformity, is the external aspect more easily evaluated by the consumer. It is decisive in those products like leafy vegetables or unripe fruits such as cucumber, snapbeans, and others where an intense green is associated with freshness and pale green one or yellowing to senescence. Colour is also an indicator of fruit ripeness and very important in those where no substantial changes take place after harvest (non-climacteric fruits), such as citrus, pepper, eggplant, and cucurbits in general. In fruits that suffer changes after harvest (climacteric) colour is less decisive and basically indicates the degree of ripeness, as for example tomato, pear, banana, etc.

Consumers assign to size a certain importance (Figure 63) and at equivalent quality, intermediate sizes are preferred. In fruits that are naturally large such as pumpkins, watermelons, melons, etc., there is a very defined trend towards sizes that can be consumed by a family (1-2 kg) in a relatively short period (1 week). Size is one of the main indicators of the moment of harvest (Chapter 1) and in many cases it is directly associated to other aspects of quality such as flavor or texture. Such is the case of zucchinis, peas, haricot beans and miniature vegetables in general where consumers particularly value small sizes.

Gloss enhances the colour of most products, but it is particularly valued in species like apple, pepper, eggplant, tomato, grapes, plums, cherries, etc., to such a point that many of them are waxed and polished to improve their shine. In vegetables, gloss is associated in a certain way to turgidity: a brilliant green is one of the indicators of freshness. It can also be used as a harvest index in eggplants, cucumbers, squash and other fruits that are harvested unripe where the decrease in shine indicates that they have developed too much and have lost part of their characteristics of flavour and texture. On the contrary, in melon, avocado, and other species, it is indicative that it has reached ripeness for harvest.

Different sensations perceived by humans are included within the definition of texture. Thus, firmness is perceived with the hands and, together with the lips, the kind of food surface (hairy, waxy, smooth, rough, etc.), while teeth determine the rigidity of the structure that has been chewed. The tongue and the rest of the mouth cavity detect the type of particles that are crushed by teeth (soft, creamy, dry, juicy, etc.). Also the ears contribute to the sensation of texture, for example, the noises generated when chewing in those species where crispness is an important aspect (Wills, et al., 1981).

Together with flavor and aroma, texture constitutes the eating quality. An over-ripe tomato, for example, is mainly rejected by its softening and not because important changes in the flavor or aroma have taken place. Although it is decisive for the quality of some fruits and vegetables, in others it has a relative importance. In texture terms, each product is valued differently: either for its firmness (tomato, pepper), the absence of fibers (asparagus, globe artichoke), its softness (banana), juiciness (plums, pears, citrus), crispness (celery, carrot, apple), etc.

Firmness and colour are the main parameters to estimate the degree of ripeness of a fruit since this process initially improves and softens fruit texture, which together with the changes in flavour and colour, bring the fruit to reach its maximum eatable quality. However, as this process continues, over-ripeness takes place, which leads finally to tissue disorganization and decay of the product. Firmness is used mainly as a harvest index and it is measured with instruments (Figure 12) that register the force necessary for a certain deformation or resistance to the penetration of a piston of known dimensions.

Juiciness is the sensation of liquid spilling inside the mouth as tissues are chewed. The juice content of many fruits increases as they ripen in the plant. It is regulated that the minimum content that citrus fruits should have, is: 30% for Navel oranges; 35% for grapefruit and the other oranges; 25% for lemons; 33% for mandarins and 40% for clementines (Thompson, 1996).

5.3.1.2 Flavour

Flavour is the combination of the sensations perceived by the tongue (taste) and by the nose (aromas) (Wills, et al., 1981). Although those sensations can be perfectly separated one from the other, as the sensitive receptors are so close, simultaneously with the act of bringing near the mouth, of biting, chewing, and tasting, we are perceiving the aromas, particularly those that are liberated with the crushing of tissues. It is also possible, however, that certain external aspects (particularly ripeness) anticipate the flavor that should be expected when consuming the product. The human being has stored in his/her memory an enormous quantity of different tastes and aromas and, if it was eaten previously, is able to recognize them without seeing the product.

In fruits and vegetables, taste is usually expressed in terms of the combination of sweet and sour principles that are an indication of ripeness and eating quality. The content of soluble solids is a good estimate of total sugar content, and many fruits should have a minimum content of solids to be harvested (Table 14). Organic acids (citric, malic, oxalic, tartaric) are the other important components of taste, particularly in their relationship with soluble solids. As the fruit ripens they tend to diminish and so the relationship with the soluble solids tends to increase. Titratable acidity is the form of expressing acidity. The soluble solids/titratable acidity relationship is a denominated ratio and it is essentially used in citrus where it is a function of the species and of the variety. Its value is 8 for mandarins, Navel oranges, and hybrids, 7 for other type of oranges, and 5.5 for grapefruits (Lacey, et al., 2000).

Astringency (sensation of loss of lubrication in the mouth) and bitter tastes are due to different compounds. They are not frequent and when they exist, usually diminish with ripening. In those cases in which they appear naturally and represent a disadvantage, they have been eliminated through breeding programmes.

There are specific compounds that characterize certain species or a group of them, for example, pungency in the peppers denominated "hot" is basically determined by the capsaicin content and other 4 structurally similar compounds. There are also cases in which enzymes and substrata responsible for the taste are compartmentalized in healthy tissues and they only get in contact by cutting, chewing or crushing. This is the case of pungency in garlic and onion and also of the taste of raw cucumber. Cooking these vegetables whole prevents these reactions and the resulting taste is different.

Table 14: Recommended minimum soluble solid content at harvest.

Source: Kader, 1998.

There is a correlation between dry matter content and organoleptic characteristics mainly used by the industry. In general, a higher content of solids means higher industrial yield and taste. This is particularly important in dehydrated products. In potato, a higher content of dry matter (measured as specific gravity) is associated to a better cooking quality. For the fresh market, however, dry matter content is not used as an indicator of the time of harvest and/or organoleptic quality, except in the case of avocado where there is a close correlation with the oil content. Depending on the variety considered, avocados with a dry matter content lower than 21-23% should not be marketed (McCarthy, 2000).

The aroma of fruits and vegetables is due to the human perception of numerous volatile substances. Refrigerated fruits and vegetables are less aromatic since volatile liberation diminishes with temperature. As well as in the case of taste, many aromas are liberated when tissues lose their integrity.

5.3.1.3 Nutritive value

From the nutrition point of view, fruits and vegetables are insufficient to satisfy daily nutritional requirements, essentially because of their low content of dry matter. They have a high content of water and are low in carbohydrates (excepting sweet potatoes, potatoes, cassava, and other underground organs), proteins (except for legumes and some crucifers) and lipids (except avocados), but they are, in general, a good source of minerals and vitamins. Different countries have made tables of recommended daily consumption, the best known being probably the U.S.R.D.A. (United States Recommended Daily Allowances) (Table 15). These tables are only for reference and they indicate the capacity of foods to satisfy the daily needs for certain nutrients. The conditions of cultivation, varieties, climate, and preparation affect the actual content of nutrients.

Dietary fiber can be defined as the vegetable portion that cannot be degraded by the enzymes of the human digestive tract although its components are anaerobically metabolized in variable proportions by the colon microflora. The optimum daily ingest for a healthy adult is 25 to 30 grams and the contribution of certain fruits and vegetables to the minimum needs is shown in table 15.

The discovery that certain foods have biologically active compounds, beneficial to health beyond basic nutrition opened a new stage in nutrition science. These compounds or their metabolites that have been denominated "functional", help to prevent diseases like cancer, have a protective effect on cardiovascular problems, are neutralizers of free radicals, reduce cholesterol and hypertension, prevent thrombosis, besides other beneficial effects. Those foods that contain them are also called "functional" although other names such as "pharmafoods", "nutraceuticals", and others have been proposed. As most of these compounds are of plant origin, many authors call them phytochemicals. Fruits and vegetables are rich in phytochemicals like terpenes (carotenoids in yellow, orange and red fruits and limonoids in citrus), phenols (blue, red and purple colours of cherries, grapes, eggplant, berries, apples and plums), lignans (broccoli), thiols (sulfur compounds present in garlic, onion, leek and other alliums, cabbages and other crucifers) and others.

Table 15: Content of essential nutrients (* = good; X = very good; XX = excellent; exceed daily requirements).

Source: The Packer, 1996; Produce Marketing Association, 2000.

5.3.1.4 Safety

Fruits and vegetables should be attractive, fresh, nutritive and with a good appearance and presentation. Besides these characteristics, their consumption should not put health at risk. The consumer has no way to detect the presence of dangerous substances on food and he/she depends entirely on the seriousness and responsibility of all the members of the production and distribution chain. Necessarily, he/she has to trust them, in addition to the usual precautions of washing, peeling and/or cooking the product before consuming it. However, this trust is very volatile and any suspicion about safety has a tremendous impact at consumer level. Among the most relevant examples it is worth to mention the epidemic of cholera in the 90s in Latin America that reduced the consumption of vegetables in many countries of the region for almost one year. Another example may be the two grapes with dangerous residues detected in the 80s in an entrance port of the USA, which severely affected Chilean exports. Also about that time, the Alar (daminozide, a growth regulator used to control fruit set) scare considerably diminished the consumption of apples in the United States.

Food safety is the absence of substances dangerous for health and particularly in fruits and vegetables, the presence of pesticide residues on the product has been the main concern for consumers. However, there are many other contaminants potentially as dangerous such as the presence of pathogenic microorganisms, mycotoxins, heavy metals, and others.

As fruits and vegetables are consumed fresh and are many times not peeled, all organisms pathogenic to humans which are carried on their surface constitute a potential danger. The hygienic and sanitary measures to reduce the food risk have already been described in the previous chapter. Bacteria, like Shigella spp., Salmonella spp., Aeromonas spp., Escherichia coli, Listeria monocytogenes and the toxins produced by Clostridium botulinum and others, have been identified as responsible for illnesses associated with the consumption of fruits and vegetables. The Hepatitis A virus has been detected on produce as well as parasites like Entomoeba histolyca, and Giardia lamblia (Table 12).

Agrochemicals are one of the tools that man has used to satisfy the growing need for food. They are the herbicides, insecticides, fungicides, fumigants, rodenticides, growth regulators, waxes, disinfectants, additives and all other products of a chemical nature used during production or post-harvest handling. Their residues have always been a major concern, although the advances in chemistry and biochemistry, the better understanding of ecology as well as pests and diseases, and the growing use of non-chemical control methods, have made the present world a much safer place. Today's agrochemi-cals are less toxic and persistent, their degradation products are generally innocuous and better laboratory methods have been developed for their detection. Additionally, there is a greater consciousness about their use, waiting times, doses, etc.

Each country has its own legislation in terms of the Maximum Residue Levels (MRLs) within the framework of the Codex Alimentarius Commission or other international organizations. An MRLor tolerance is the maximum concentration of pesticide residue allowed resulting from its application according to correct agricultural practices.

Agrochemical use should be within the Good Agricultural Practices framework to guarantee maximum safety and to minimize risks to the consumer's health. Specific products should be used to control pests or diseases following the manufacturer's indications, particularly those refering to crops on which they can be used, as well as minimum waiting times between application and harvest.

Other health hazards are the presence of nitrates in leafy vegetables, oxalates in some species and heavy metals accumulation, particularly when sewage is used as fertilizers or organic amendments. Some toxicity may exist in some natural compounds produced by the crop itself or by the fungi that colonize its surface like the micotoxins.

5.4 Obtaining a product of quality

Producing a quality product begins well before planting the seed. Soil selection and preparation, its fertility and irrigation aptitude, weed control and crop rotations, variety selection and other decisions have an influence on the quality of the product. In the same way, quality is affected by the climatic conditions during the growing period, as well as irrigation, fertilizations, control of pest and diseases and other cultural practices. Harvest is the end of cultivation and the beginning of post-harvest actions during which preparation for the market, distribution, and sale take place.

Fruits and vegetables are highly perishable products and before being detached from the mother plant all demand water and nutrients. Once harvested, however, they depend on their reserves to continue living. Respiration, transpiration and the continuous changes taking place determine the internal and external quality. Deterioration rates depend on the type of product, growing conditions and other factors, but mainly on the conditions in which the produce is maintained after harvest such as temperature, relative humidity, movement and composition of the air, etc. Post harvest changes can only be delayed within certain limits and thus preparation for the fresh market should be quick and efficiently performed to avoid quality losses.

Besides their natural deterioration, rots and physiological and mechanical injuries already described in previous chapters, are also responsible for loss of quality. Post-harvest losses due to microorganisms can be severe, particularly in warm climates with a high relative humidity. Rotting produce contaminates the rest and under these conditions ethylene production is stimulated accelerating the rate of deterioration.

Most of the fungi and bacteria that attack fruits and vegetables after harvest, are weak pathogens and they mainly invade tissues through wounds. (Wills, et al., 1981). Injuries produced during handling provide numerous entrance routes to these pathogens although some of them are able to invade healthy products. Unripe fruits are usually more resistant to pathogen attack. It is also possible that infection occurring at the immature stage shows up later, when the natural defenses are weakened by the ripening process (Dennis, 1987). A good disease control program at field level reduces the source of inoculum and the risks of infections after harvest facilitating the control of post harvest diseases. Also, careful handling during harvest and packing operations reduces the physical damage that facilitates the establishment of microorganisms. Controlling temperatures to which produce is exposed is one of the main tools to control post harvest diseases since it diminishes the metabolic activity of the microorganisms and, by reducing the rate of the ripening process, the natural defenses of the product are kept high. Controlling the relative humidity, particularly to avoid the condensation of water on the product, as well as controlled atmospheres is also useful in the control of post-harvest diseases.

5.5 Towards total quality in fruits and vegetables

The concept of quality as a way to differentiate products has been recognized for years. As local or regional trade internationalizes, quality consolidates as the main competitive tool for excellence, reinforcing the need to establish standards to separate quality into categories or degrees, as well as to define the limits of allowed defects. Nowadays, domestic and international trade of fruits and vegetables is regulated by quality standards in most countries, providing a common language among the different participants of the production-commercialization-consumption chain. Standards are also the legal framework to settle commercial disputes and are useful as a basis for reporting on market prices as prices only can be compared between the same quality category.

The quality system established by the standards is known as "Inspection for quality" (Table 16) where representative samples at the final stage of preparation for the market should fulfill the specified limits and their tolerances. Although it is easy to apply, it has, at least, two big disadvantages: firstly, they are not totally adapted to highly perishable products where quality varies continually. Secondly, its application does not improve the quality of the product, it only separates in degrees the quality that comes from the field.

At the same time that quality standards developed and were applied, new ideas began to be conceived by industry. Firstly, it became evident that a systematic and preventive approach was much more effective and economic to improve quality than the elimination of the faulty units at the end of the line, when the production and packaging costs had already happened. Secondly, it became clear that the quality concept extends beyond the product itself, since it is affected by the systems and procedures involved in the production and preparation for the market. Finally, the consumer's opinion begins to be more and more important. It is no longer sufficient for a product to be technically perfect and produced in an economically profitable way, it is also necessary to satisfy the consumers'expectations of quality.

The application of statistics to control the variability of the different units in the production lines gave birth to the system called "Quality control" or "Statistical Quality Control", which was adopted by most manufacturing companies in the first half of the 20th century. This method or system essentially provides the analytic tools for monitoring the production process and for taking measures when variability exceeds certain limits considered as normal. Its application improves the quality of the process contributing greatly to improve the quality of the product. They are tools that can be applied at the fruit and vegetables packinghouse level.

This system was transferred to Japan after World War II where it evolved into what today is known as "Total Quality Management" or simply "Total Quality". Total quality is today the most complete conceptual framework to assure quality to which each person or activity within the production process is committed, aiming at zero defects and customer's complete satisfaction, even going beyond his/her expectations. At the same time that TQM was developed, the concept of "Quality Assurance" was coined in Europe. Its scope is slightly narrower than TQM, but a lot easier to implement and probably better adapted to fruit and vegetables. It is defined as all those planned and systematized actions necessary to guarantee that the product or service will satisfy the requirements of quality. It usually requires the fulfillment of certain rules, protocols, or standards developed specifically and with a certification by an independent company authorized to grant it. The ISO system is probably the best known and within it the series 9000.

Table 16: Comparison of the main quality systems

It is also appropriate to mention the HACCP(Hazard Analysis Critical Control Points) system, designed specifically to guarantee that food is not exposed to any type of contamination that could put health at risk. Today, this method is recognized internationally as the logical and scientific tool for all food quality systems. It is also preventive in nature and the key element is the identification of the critical points, within the process, where quality should be controlled to prevent, eliminate or reduce to acceptable levels all possible safety risks. The HACCP system is required today in the USA and other countries to import meat, fish, eggs, and other foods. Up to now, it is not required for fruits and vegetables, although different export countries are already implementing it to assure a superior quality of their products. The logic of the HACCP can be applied to the detection of other defects of quality.

Although all these systems have their origin in industry, their application extends to other sectors. Agriculture, and particularly the production of fruits and vegetables, is now incorporating many of the methods and ideas conceived by the industrial sector because the basic principles are not only applicable but also recommendable for highly perishable products where quality deteriorates quickly. Several export companies have implemented the HACCPtogether with the ISO 9002 certification, which guarantees food safety within a system of quality assurance. Akey concept is that quality systems are not mutually exclusive but rather they overlap widening the application approach, extending beyond the product itself and embracing the preparation process, inputs, suppliers and intermediaries, besides the incorporation of the feedback from the client or consumer for its continuous improvement.

The basic principles of total quality can be summarized in the following way:

• The consumer is always first

• Each operation is part of a process

• Quality improvement never ends

• Quality is made, not controlled

• Prevention of quality problems is made through planning.

• The desired product should be obtained at the desired moment. Post harvest handling should be appropriate to reach the desired market under the desired conditions.