EXAEDIFICO Optimizing Postharvest Handling and Maintaining Quality of Fresh Pineapples

Pineapple is the third most important tropical fruit in world production after banana and citrus. As much as seventy percent (70%) of the pineapple produced in the world is consumed as fresh fruit in the country of origin.  Accordingly, the significance of reducing postharvest losses and maintaining quality from the point of harvest as the fruit travels through the various marketing channels until consumption cannot be underscored and is the responsibility of producers, handlers, packinghouse personnel, marketers and consumers.

Cultural Practices

It is important that fruits are produced under optimum conditions as the internal and external quality of Fruit at harvest is determined by several factors. These include: quality planting material, optimum nutrition, adequate irrigation, drainage and spacing and proper management of pest and disease.

Development and Maturation

Pineapple has three distinct phases of growth:

Ø  the vegetative phase of leaf growth;

Ø  the generative phase of fruit growth; and

Ø  another vegetative phase of shoot growth.

Pineapples contain negligible starch reserves for sugar metabolism after separation from the plant, and any acid reduction or flavour development after harvest is minor. In order for the fruit to attain its maximum sugar content and its best flavour it must be allowed to ripen completely on the plant. If harvested too early, the pineapple fruit would be flavorless with poor aroma and the almost colourless flesh would be very acidic and extremely susceptible to internal browning and chilling injury. Fruit harvested too late, would be very sweet, with low acidity and with a distinct yellow color flesh. These fruits are very fragile, and susceptible to fungal attack with the possibility of the onset of fermentation taking place.

Origin of the Pineapples

View of Mt. Matutum from the Pineapple Plantation at the base of the volcanic mountain located in Polomolok, South Cotabato on the island of Mindanao, Philippines. 

Under the shadows of Mt. Matutum, in Polomok lies the world's largest integrated pineapple plantation producing Fresh Pineapple (Class A) / M2 directly adjacent to Dole Philippines. EXAEDIFICO obtains it pineapples and utilizes the same growers that supplies Dole Philippines.  Polomolok is also dubbed as “Pineapple country”; its vast and fertile fields are awesome scenery that is waiting to be discovered. These lush and green-coloured pineapple fields are stretched across the interior landscape of the region as far as the eye can see. The gorgeous fields have a fresh, tropical smell of ripe pineapples and kalachuchi flowers; it gives a breathtaking view that is a constant reminder of the beauty of the region. The delicious pineapples from Polomolok have a unique sweet and tangy taste; they are consumed locally as fresh fruit and used to produce juice and slices for exports. The pineapple has become a symbol of welcome and hospitality all around the world and is known as one of the most versatile food. A visit to Polomolok would not be complete without taking home some freshly harvested “Queen of Fruits”.

Mt. Matutum, a volcano that nourished the soil of the province, giving food and life to the people of South Cotabato, is truly a gift of Mother Nature.

There are a lot of 'plantations' in the Philippines. On these large commercial agricultural businesses one single product (plant) is dominating.  In the Philippines there are among others banana, coconut, mangosteen and pineapple plantations. Some of the world’s biggest pineapple plantations (by Del Monte and Dole) are located in the Philippines on the island of Mindanao. The Philippines is the largest producer of pineapples in the world.

Pineapple Plantation fields stretching over 38,000 hectares at the base of Mount Matutum located in Polomolok, South Cotabato on the island of Mindanao, Philippines.

The Growers:

There are a number of production modes employed by multinational companies and large domestic firms.  These include contract growing, lease arrangements, company-managed farms and joint ventures.  No data are available on the number of hectares cultivated under each production mode.  The following are common growership agreements:

• The exporter advances 100% of the growers’ costs like payroll, fertilizers, chemicals, packaging materials and overheads. In exchange, the grower commits to sell all his produce to the exporter at a price agreed at the start of the year.

• The exporter advances portion of the growers’ costs like irrigation and aerial spray.  The grower commits a certain volume of only, say, 2,000 boxes/ha at a fixed price agreed at the start of the year. He has the option to sell the remainder of the produce to the exporter or other traders.

• A grower is independent of the exporter and decides whom to sell his produce. The pineapple contract growing scheme is a joint venture between a grower and a company.  Under this scheme, a grower is contracted by the company to plant his/her land with pineapples that will be exclusively purchased by the latter.  In principle, a 70%-30% sharing of production cost is observed by the company and the grower.  The 70% portion comes in the form of financing and technology.  The company provides the capital for farm inputs and the infrastructure facilities, equipment, and technical know-how in the production of pineapples.  This amount is eventually deducted from the sale of processed pineapples. 

The grower’s 30% is in the form of land and labor, which the growers provide and pay for.  The revenues derived by the grower are net of the deductions for the financing provided by the company.  The grower is tasked to manage the land and provide labor while the company exclusively buys and exports the pineapples, bananas, mangoes and other tropical fruits produced.

The Process:

Quality Indices

The fruit must be:

a)      normally developed, sound and undeformed;

b)      of a satisfactory maturity and colour;

c)       free from any abnormal flavour or colour;

d)      exempt from parasites or physiological diseases;

e)      free from holes, bruises or signs of shocks due to careless handling;

f)       free from deep cracks;

g)      exempt from sunburn symptoms;

h)      topped by a symmetrical crown with no visible scar if it has been shortened;

i)        in possession of clearly-sectioned peduncle measuring 5 – 20 mm long.

Harvesting

Harvesting pineapple fruits early in the morning or late in the evening or during the night would provide protection from the sun and this could reduce the heat load on harvested fruits during pre-cooling. Pineapple fruits are harvested by bending them over and twisting to remove fruits from the stalk. The quality of the crown is an indicator of freshness and therefore crowns should be green with turgescent leaves. The crowns should not have a withered appearance, which may be due to insufficient irrigation, extensive refrigerated storage, and storage at temperatures below 7 – 8 ° C, low relative humidity, and delays during marketing and incorrect application of ethephon. The height of the crown should also correspond to the dimensions of the packaging that will be used. For small fruit, the size of the crown should be between a third and two-thirds the height of the fruit. For market requirements, it is possible to limit the size of the crown. This operation must be done two months before harvest by destroying the heart of the crown with a “gouge”, without leaving a visible scar. For larger fruits, the crown should be between a quarter to a half the size of the fruit. The crown should not be shortened at the time of harvesting because this practice would leave a wide wound which spoils the appearance of the fruit, favours the growth of fungi and could cause fruit rot. The manner in which the peduncle is cut at harvest is important to optimize overall quality and appearance. Peduncles should have a clean cut and be 5 – 20 mm long, especially when fruits have to be transported in a vertical position. Sunburn is common during hotter periods (>35°C), when the fruits are not shaded. Sun scorched fruits show a bleached yellow-white skin, which turns pale grey or brown, and damage to the flesh underneath. These damaged areas are more susceptible to attack by disease organisms, particularly yeast and bacteria.  The fruits are protected by outer leaves to prevent sunburn in the field. Harvested fruits are placed in baskets, crates or bags by hand, upside down on the crown to avoid injury. When harvesting containers are filled they should be transported as soon as possible to the packing house.  Disinfection of the peduncle should be carried out less than three hours after harvest to efficiently prevent the penetration of the fungus Thielaviopsis paradoxa which is responsible for black rot (water blister) of the fruit. The dry leaves at the base of the fruit should be trimmed before disinfection. They may contain mealy bugs or fungi.

Pineapples transportation to on site packinghouse.

Packinghouse Operations:

v  Pre-cooling

On arrival at the packinghouse, fruits are unloaded by hand and submerged in water or allowed to slide out of the container into the water. The water in the dump tanks should be chlorinated and replaced frequently to prevent a build-up of disease organisms.  Fruits with high flesh translucency are called “sinkers” and must be separated at this stage. The “sinkers” are very fragile and have limited shelf life. High translucency is also associated with bacterial and yeast fermentation and acetic acid souring during handling, shipping and marketing. Care must be taken to avoid mechanical damage to the crown and mechanical injury to the fruit shell. The purpose of pre-cooling is to remove field heat.  If pineapples are to be exported to the destination within 2 – 3 days of harvesting, as with air-shipments, then pre-cooling is advisable.  Pineapples transported by sea should preferably be pre-cooled prior to loading into containers. By submerging fruits in water as described previously, hydro-cooling is being achieved. Temperature controlled rooms can also be used but cooling rate is slow particularly if stacking and spacing are not adequate to allow free and even air flow or if the refrigeration capacity is inadequate. A forced air cooling system is more efficient but this requires a specially designed unit and compatible packaging.  Pineapples should be pre-cooled to a minimum of 8°C.

v  Grading

Fruits are graded based upon certain characteristics: degree of skin colouration, size (weight), absence of defects and diseases, and in keeping with other market requirements.

v  Application of fungicides and waxing

Pineapple fruits are commercially treated with a fungicide such as Dowicide A (Sodium 2-phenly phenoloate) at a concentration of 7g per liter of water in either a dip or a spray application to control postharvest fruit rot.  A wax, which may contain polyethylene/paraffin or carnauba/paraffin-based, could also be applied to the fruit with the fungicide.  Waxing could reduce internal browning, a symptom of chilling injury. Waxing also reduces postharvest water loss and improves fruit appearance.

v  De-greening of fruit shell

Postharvest use of ethephon could result in uniform skin de-greening but this could also lead to a shortened shelf-life. The need to de-green is related to the consumer’s perception that a ripe pineapple must have a yellow skin. Ethylene treatment has no significant effect on flesh TSS or acidity.

v  Packaging

Pineapple fruits could be packed 12.0 kgs. Net weight = 1 box for shipment with 5, 6, or 7 pieces per box. Moisture Content:  Not more than 10%, Packaging Materials Corrugated Fiberboard container for 12 kgs. Pineapple box HSC type with hand and vent holes. Whichever type of package is used, certain precautions must be followed: the package should be dry, odorless and sufficiently rigid to permit stacking; cartons must be adapted to the size of the fruit to avoid crushing (bulging cases) or crushing the crown; dimensions of the cartons must be compatible with the modern techniques of palletisation and the use of the containers, which contributes to the quality of the fruit; and there should be no transfer of toxic matter from the package to fruit. Transportation of fruits packed in a horizontal position is more liable to lateral shocks.  Absorbent pads are placed at the bottom of the carton and between layers if fruit are alternated horizontally within the carton.

v  Sanitation of packinghouse

Packinghouse sanitation is an absolute requirement for controlling postharvest diseases of pineapple fruits. Dirty or soil-contaminated fruit should be washed outside the packinghouse, as partially decayed fruits are loaded with microbes and are noted for sticking to surfaces. The water used in fruit dumps, flumes, or washers must be kept free of postharvest pathogens.  If the water becomes contaminated with decay pathogens, the fruits will become inoculated and a large number of fruits would decay before they can be marketed or consumed. Chlorine is the principal chemical used in sanitizing solutions mainly because it is safe, effective, and in-expensive and leaves no chemical residues on the fruit.  Clean and sanitize packing areas, storage rooms, fruit containers and equipment. Prime sites for pathogen growth are areas that remain wet e.g. brush/sponge rolls and floors. Remove all plant debris left on the packing line or packinghouse floor. Plant residues in an environment where moisture is available plus microbes at warm temperatures form biofilms.  While sanitizers can prevent biofilm formation, they do not penetrate biofilms that have built up over time.  Some important sanitation tips for packinghouses include: (i) pre-rinse equipment or walls (ii) visually inspect surfaces (iii) scrub from top downward (iv) handle fruit carefully to prevent wounds (v) remove injured fruits from facilities (vi) maintain an effective pest control programmed (vii) prepare cartons only as needed (viii) monitor worker hygiene (ix) apply strict temperature management guidelines.

v  Storage of pineapples

Store pineapple fruit at 7.5 – 12°C and 90 – 95% relative humidity.  At 0 – 4°C, fruits may store for weeks, but upon transfer to non-refrigerated conditions, the fruit would not ripen and severe chilling injury symptoms would appear. Half-ripe (M2 – M3) fruit can be held for about 10 days at 7.5 – 12.5°C and still have about a week of shelf life with no chilling-induced browning. The maximum storage life at 7°C is about 4 weeks, but when transferred to ambient conditions, chilling injury develops within 2 – 3 days. Symptoms of chilling injury include: wilting, drying and discolouration of crown leaves, failure of green shell to turn yellow, browning and dulling of yellow fruit, internal flesh browning. Susceptible fruits are generally lower in ascorbic acid and sugars and are opaque. Partial to complete control of chilling injury symptoms has been achieved by waxing, heat treatment, modified atmosphere packaging, ascorbic acid and application of the ethylene inhibitor 1-methylcyclopropene (1-MCP).

v  Palletisation

Palletisation is essential to minimize fruit damage due to multiple handling. Movement of fruits within pack-houses or during temporary storage should be aided by palletisation.

Preparation Of Pineapple For Fresh-Cut Purposes

Fresh pineapples at the M2 or M3 stages of maturity are suitable for fresh-cut purposes. Studies conducted by Mohammed and Wickham (2002) indicated that fresh-cut pineapple slices treated with antioxidants in a combined form of 300ppm ascorbic acid plus 200ppm 4-hexylresorcinol effectively reduced browning and microbial spoilage during refrigerated storage.

EXAEDIFICO Recognizes Potential Postharvest Losses:

·         Fruit bruising

o   Fruit bruising is a major problem during harvesting and packing. The bruised area leads to leakage of cell content and provides openings for saprophytes and disease organisms. Translucent fruits are highly susceptible to bruising. The bruised flesh appears slightly straw-coloured and becomes gray with time.

·         Black Rot

o   Black rot caused by Ceratocystis results in a black watery rot of the flesh and a thin brittle skin. Infection usually occurs through the cut stem or through damaged areas, but can generally be controlled by prompt treatment with either Dowicide A or Benlate.

·         Black Spot or Brown Spot

o   Black spot or brown spot caused by Penicillium finiculosum and Fusarium moniliformae results in browning and sinking of the eyes and a browning of the internal fruitlets. Incidence is not usually detected until the fruit is cut. The diseases are believed to be caused by mite damage in the field allowing entry of the fungi. Pre-harvest spray regimes are required to control the mite population.

·         Endogenous Brown Spot:

o   This is a physiological disorder characterized by watery spots which eventually coalesce and turn brown. The incidence is found in certain varieties and production areas and is generally enhanced during long term storage.

·         Flesh Translucency

o   This is a physiological disorder where the pineapple fruit flesh shows water soaking symptoms. Opaqueness as opposed to translucency lacks the presence of small air bubbles in the intercellular spaces of the fruit flesh tissue. The causes of translucency are unknown but it has been associated with high nitrogen, clones, treatment with fruit-enlarging agents, irrigation rate, planting density, larger crowns and environmental factors (Soler, 1993).

·         Broken and Hallow Core

o   A transverse break in fruit flesh that occurs early in development is marked by a slight depression on the outside of the fruit. The break leaves a gap of 2 – 10 mm in the flesh and the tissue becomes corked and brown, sometimes accompanied by rot. Hollow core is a vertical crack in the core that becomes dry and leathery and it may extend to the peduncle. The fruits are usually opaque and the conditions are thought to be due to desiccation.

·         Rodents, Birds and Insect Damage

o   Rodents, birds, insects (crickets and grasshopper) and wind may cause wounding in young fruit that will heal over with hard, corky, scar tissue. Fruit growth may tear open this injury and lead to misshaped fruit.

EXAEDIFICO may not be involved in production but it requires very high quality standards for the pineapples, bananas, mangoes, coconuts and other fruits/vegetables they export.  Before exportation quantity, quality and weight to be conducted by SGS or any International certified agencies at seller’s cost at port of loading. EXAEDIFICO prefer to deal with large companies rather than small/individual growers because it allows them to exercise control over quality and volume requirements. The large companies provide their own agricultural chemicals, aerial spray, cleaning, sorting, packing (using their own box plant), and transportation from farm to the port.  While multinational companies deduct expenses incurred from the quoted price for the small growers, they no longer deduct from the large contractors since they do the services normally provided by the multinational companies.