Trade Of Horticultural Produce Biology Essay

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The trade of horticultural produce at the local and more importantly, at the international level is governed by certain factors. These factors necessitate the design and implementation of measures to make the produce competitive. These factors can be considered in two ways-quality and safety factors (Kader and Rolle, 2004).

1.1 Significance and inter-relationships of different attributes of horticultural produce

Horticultural produce particularly fruits; vegetables, roots and tubers have formed part of the daily diets of humans supplying nutrients for the well-being of the human body. With the development of the horticultural industry in modern times, produce are moved from production areas to retail outlets either locally or internationally. For this reason, the produce supplied plays two-pronged function of meeting the safety and quality requirements of the importing countries and providing income to the exporting countries when they meet the buyers specifications (Thanh, 2006).

1.2 Quality attributes of the produce

The term "Quality" is "evasive" in its definition taking different descriptions. Its definition depends on the user, the product, the value or even the manufacturer. In general terms however, quality is defined either as "conformance to requirements" or more popularly as "fitness for use" (Mitra, 1998). It involves giving consumers what they need, at the right time, at the right price and every time they need it. Quality attributes associated with horticultural produce include structural characteristics such as size and shape and sensory characteristics such colour, flavour/ taste.

Production stageDetermination and maintenance of quality through the supply chain

Harvesting (harvest maturity)

Agronomic factors (fertiliser and water application)

Genetic factors (Varietal selection)

Climatic factors (Temperature and light intensities)

Postharvest stage

Transport, distribution and retail

Packaging (traceability)

Sorting and grading (size, colour and shape)

Storage (temperature management)

The quality attributes of fruits, vegetables, roots and tubers are determined pre-harvest and at harvest and these attributes are not increased but are either altered or maintained at the postharvest stage. The determinants of the quality are varietal selection, agronomic practices, climatic conditions and maturity at harvest. At the postharvest stage, sorting and grading at the packhouse allows for selection of appropriate-sized, shaped and coloured produce. Temperature management during transport and storage reduces metabolic rate and maintains the quality of the produce. Packaging protects the produce from physical and microbial damage and incorporates information of the produce for purposes of traceability. Management of temperature during distribution and proper display of produce under appropriate conditions of light can also influence its quality (Lee and Kader, 2000; Hewett, 2006).

1.2.1 Structural characteristics - size and shape

Produce are visually appraised by their size, colour and shape. Size is often associated with maturity and variety of a particular produce. If the produce is either too big or too small in relation to the specific crop or variety, in question then is it often disregarded by the retailer as well as the consumer. Also, shape is characteristic of specific produce in that a malformed or shrivelled produce will be selected against by consumers as this is atypical of the particular produce in question and considered unfit for consumption (Kader and Rolle, 2004).

1.2.2 Sensory characteristics

a. Colour

The colour is the most common feature that determines consumer perception of the eating quality of the produce. Some produce by nature ripen to become red or yellow (most fruit); some mature and still look green (most vegetables). In the former, the produce quality is synonymous to ripeness and can be harvested at that stage while in the latter where colour change does not occur, they are picked at "readiness to harvest" stage. Therefore, the buyer equipped with this knowledge would decide to buy a particular produce based on the colour characteristic of that produce. A blotchy colour will be perceived as an off-type which is unfit for consumption (Camelo, 2004). Crisosto (2009) found that in some fruits such as peaches and nectarines, mechanical damage can cause a reactive discolouration (inking) on the fruit skin resulting in economic losses.

b. Texture

Texture refers to the feel of the produce. At the retail outlet, it could be felt by hand but can be determined by mouth feel (smooth, crispy etc.) after purchase. The texture determination by hand could refer to the firmness or smoothness of the produce. For instance, the skin of apples is smooth while that of oranges are rough but in both cases they need to be firm to be acceptable to the consumer. Softening of fruits could result from cell wall degradation due to metabolic breakdown of assimilates, water loss in dry storage conditions or microbial infection. All these scenarios are unacceptable to the buyer and more serious is the latter case. Spoilage microorganisms such as Alternaria alternata or Botrytis cinerea has been associated with softening of tomato fruits (Bombelli and Wright, 2006).

c. Flavour

The flavour as determined by a characteristic aroma reflects the eating quality of produce. Therefore; any produce with off-flavour will not be regarded as fit for consumption. For this reason, monitoring systems are aimed at ensuring the adoption of production and handling practices that helps to maintain the natural flavour and taste of produce. As indicated by Kader (2008), the flavour quality of the produce is affected by genetic, pre-harvest, harvest and postharvest factors. There is genetic variability in volatile compounds possessed by fruits and vegetables and these are affected by pre-harvest conditions such as fertiliser and irrigation regimes, maturity stage of harvesting and postharvest handling. The storage of produce in elevated carbon dioxide atmosphere can lead to anaerobic respiration, producing ethanol, acetaldehyde and lactic acid and resulting in off-flavour production.

d. Nutritional value

Nutritional quality is the least attribute considered in consumers purchase decision. Apparently, because the nutrient content of the produce cannot be determined in the usual way as in the other quality attributes. Nutrients of major concern include vitamins such as A, B and C, minerals such as calcium and iron and essential amino acids as well as dietary fibre. The nutritional composition of fruits and vegetables can be influenced by genetic make-up of the produce achieved through breeding. Climatic factors such as temperature and light is known to affect nutrient levels in fruits and vegetables. High temperature and light intensity are known to increase ascorbic acid content in tomatoes at pre-harvest while high nitrogen and water application reduce it. Postharvest heat treatments in fruits and vegetables however results in loss of vitamin B and C (Kader, 2008; Wills et al., 1998; 2007).

1.3 Safety attributes of the produce

Unlike the quality attributes, safety factors associated in horticultural produce cannot be easily perceived by the consumer unless by laboratory analysis or when they manifest themselves in a form of sickness after consuming an unsafe food. Food safety is therefore defined as "the assurance that food will not cause harm to the consumer when prepared and/or consumed according to its intended use" (CAC, 2003). Safety attributes considered as "hazards" are explained in three ways: physical, chemical and biological hazards.

Physical hazards

These are tangible materials that are found in food and which if ingested can cause harm to the consumer. They include broken twigs, thorns or spines in harvested horticultural produce. However, they do not pose significant risk as their detection and occurrence are almost negligent to cause harm (New South Wales food safety authority, 2009).

Chemical hazards

Chemical hazards that occur during production, handling, storage and marketing of horticultural produce include agrochemicals (pesticides), environmental pollutants such as lead, and mercury, lubricants from machinery as well as sanitizing agents. Naturally, some crops produce defence chemical which at higher levels are unsafe for human consumption. Examples are potatoes which produces glycoalkaloid and bitter cassava that produces hydrocyanic acid. In a study by Saldana et al. (2007), pregnant women exposed to pesticides as well as phenoxy herbicides are prone to gestational diabetes while a related study implicated agrochlorines such as endosulfan and dicifol in autism spectrum disorders in children when their mothers are exposed in early pregnancy.

Biological hazards

Biological hazards arise from contamination of microbes or their toxins. In the production of horticultural produce, the microbes of concern include:

Salmonella spp. - an enteric bacterium that can cause typhoid and gastrointestinal infection when ingested. Between 1996 and 2006, the UK recorded about 88 outbreaks of salmonella from lettuce contamination while Canada recorded 25 outbreaks for the same period with sprouts as the implicated commodity (FAO/WHO, 2008).

Clostridium botulinum - this is found naturally in the soil and unlike Salmonella spp., they form neurotoxins which when ingested even at very low doses causes paralytic illness (botulism) and can result in death. In 1991, home-made canned tomato was implicated in three cases of botulism in Ontario, Canada with moderate to severe symptoms (Loutfy et al., 2003).

Escherichia coli - also enteric and the most important member of the group is E.coli 0157:H7 whose toxin can cause illness to the consumer and sometimes death. In 2006, the USA recorded a nationwide outbreak of E.coli O157:H7 which infected 205 and killing at least three people. The infection was implicated on bagged fresh spinach (DeWaal, 2007).

Parasites such as Cryptosporidium parvum- it is a parasite that is transmitted through faecal-oral route and infection can occur with the ingestion of as low as 10-30 oocysts. Sysmptoms include diarrhoea, abdominal pain and nausea. In 2008 in Finland, 72 people were infected though the consumption of contaminated mixed salad (Ponka et al., 2009).

1.4 Systems designed to manage the safety and quality of horticultural produce

Codex Alimentarius (food code)

Before the 1960's, countries and regional bodies had food standards implemented to protect consumers within their administrative boundaries. As trade expanded beyond country and regional boundaries, there arose the need for a harmonised standard with a global influence. To this effect, the Food and Agriculture Organisation (FAO) of the United Nations in 1961 established the Codex Alimentarius (food code) which is a compilation of different standards pertaining to the safety and quality of food. It has since being administered by a joint commission (Codex Alimentarius Commission) of the FAO and the World Health Organisation of the United Nations with a binding compliance in international trade (FAO/WHO, 2006).


With increasing food safety concerns across the globe, the Codex Alimentarius (Food Code) Commission (CAC) has recommended for adoption of a harmonised and internationally accepted standard, in this case HACCP for the maintenance of food safety throughout the food supply chain i.e. from the farm to the fork. In general, the CAC emphasises that food and food products shall be safe and suitable for human consumption, free from off-flavours and any objectionable matter. Unlike the traditional quality control measures which rely on terminal sampling for assessing potential hazards, HACCP is a food safety system which adopts a systematic and preventative approach at identifying and controlling potential hazards that are critical to food safety. This system identifies seven basic steps known as the seven principles of HACCP to identify and control food safety hazards or reduce them to acceptable levels throughout the chain (CAC/RCP, 2003: FAO and WHO, 2007).

EC Regulation on pesticide residues on food and feed of plant and animal origin

Producers of fruits and vegetables use pesticides to protect their crops from pest infestation. The continuous use of these chemicals helps to control the pests but some do not degrade quickly and therefore accumulate in the produce to levels that are mammalian toxic. Therefore, consumption of such produce containing residual pesticide above certain level is unsafe for the consumer. For this reason, the European Commission (EC) has set Maximum Residue Levels (MRLs) for pesticides on horticultural produce. This is aimed at ensuring the safety of consumers especially the vulnerable group (babies, weak and vegetarians).Therefore, suppliers of horticultural produce have to comply with these standards to maintain a stake in European trade. The regulation sets limits for various pesticides and crops. Where a particular pesticide has not been specified in the regulation, a baseline of 0.01mg/kg is used as a baseline (EC, 2008).

The Ghana Food and Drugs Law

The Ghana Food and Drugs Law is a legislative instrument which was enacted in 1992 to ensure that food and drugs produced in the country or imported from outside are safe for consumption. The law is enforced by the Food and Drugs Board (FDB) and importers of food and drugs have to be registered by the Registrar Generals Department before being permitted to import into the country. Since there is no provision for food safety requirements and pesticide levels, the Board endorses the Codex standards regarding food safety and pesticide levels (GAIN, 2009).

Safe Quality Food code 1000

The Safe Quality Food code 1000 is a HACCP - based system that is designed to ensure that primary producers demonstrates their due diligence in the production of quality and safe food as per the requirements of the consumer . It was established in 1994 in Australia but has since 2004 been administered by the Food Marketing Institute in the US mandated to handle food safety issues not only in the US but around the globe. The code ensures that producers undergo a three point certification system i.e. Food safety fundamentals, certified HACCP based food safety plans and a comprehensive food safety and quality management systems. They have to demonstrate their due diligence on these three systems over the entire primary production process as well as field handling of harvested produce with reference to HACCP. It is a system that has been recognised by the Global Food Safety Initiative of the CIES and its ideal for producers engaged in direct supply to retailers or stock brokers (Safe Quality Food Institute, 2009).

Quality management Systems(ISO 9000 series)

The Quality Management Systems involves procedures and activities employed to monitor and ensure that the consumer receives a product in a way that meets is intended use. This can take a two-pronged approach- Quality Control (QC) and Quality Assurance (QA).

Quality Control simply implies detection of failure and may involve inspection, sampling the produce and analysing it to identify and eliminate the failure with respect to a particular standard.

Quality Assurance on the other hand involves the prevention of faults by taking all the precautionary measures to ensure delivery of the product as per its specifications.

In general, the QMS takes a holistic approach to include HACCP and Pre-requisite Programmes such as supplier quality assurance, operator training and hygiene, preventative maintenance, calibration of equipment, environmental hygiene and cleaning as well as pest management to comply with quality and safety standards (Mitra,1998; Evans and Lidsay,2008).

Global GAP/EurepGAP

As indicated before, EurepGAP or presently Global GAP is an initiative of retailers in the European countries who normally import horticultural produce mostly from tropical regions. In their quest to assure their customers of safe and quality produce, have instituted the EurpGAP or Global GAP initiative as a standard for the producers and/or suppliers in these regions. The term "GAP "is an acronym for Good Agricultural Practices. Crop production begins from the farm and any handling practice associated with a particular produce at the production or harvesting stage can influence the quality and safety of the produce at the postharvest level. For this reason, the EurepGAP has established critical points and compliance criteria for fruits and vegetables aimed at adopting the GAP scheme on farms. The areas of much emphasis in this respect include input supply, production practices, worker health and safety as well as environmental issues (European Commission, 2006).

Assured Food Standards

These standards were established in the 1990s in the UK by retailers of fresh horticultural produce. They have been benchmarked against the Global GAP standards and therefore implore growers to demonstrate due diligence by complying with the standards to produce quality and safe food for UK consumers. The standards place emphasis on environmental and microbiological issues throughout the supply chain. Growers certified under these standards are obliged to adopt an integrated pest management system with minimal use of inorganic pesticides (Assured Produce, 2008).