Jumbo Bins in the Fruit Growing Industry
- JUMBO BINS -
Jumbo Bins in the Fruit Growing Industry
Is plastic really fantastic?
Table of Contents
Factors influencing bin choice
Wooden Bins Vs Plastic Bins
Mpact Jumbo Bins
It is estimated that the South African agricultural industry has a total pool of about 2.7 million jumbo bins in use. Indications are that citrus fruit are almost exclusively transported in plastic bins while apples and pears each are using about half wooden bins and half plastic bins. Extensive research has been done in this industry regarding which of these, wood or plastic, are a better option for fruit growers. More than 20 years ago, in 192, Alan F. Hauff did a presentation at the Washington Tree Fruit Postharvest Conference of a study he had done on the potential of collapsible plastic bins that could be used for both storage and shiping of fruit. The study included in-depth market research and comparisons between standard wood bins and plastic bins considering the strengths and weaknesses of each; informed by industry representatives, other researchers and manufacturers. It would come to be regarded as a seminal work in this field.
Modern day fruit picking in the Bolzano region in Italy
Much of this research focused on the Bolzano region, a major fruit growing area in Italy where plastic bins had already been introduced in the 1970’s. The research included site visits to; plastic bin manufacturers, commercial storages (using only wooden bins, only plastic bins and those using both kinds) in order to discover advantages and disadvantages of both, reasons for changing from wood to plastic, or reasons to stay with wooden bins. Information was also obtained from other Researchers and extension personnel about the use of plastic bins. Hauf found that the Fruit Growers in this region had not only tried plastic bins as an alternative to wood bins, they were consciously and methodically working towards completely changing to plastic bins. The research conducted by Hauff is still regarded as a seminal work in the study of large capacity bins. Over the last 3 decades much of his research has been confirmed by other research, showing that the factors that influenced bin choice decades ago are just as valid today.
Factors influencing Bin Choice
When choosing the right bin for crops, it needs to be considered from the perspective of how it will or will not affect the fruit. Fruit and vegetables are living parts of plants that contain anything from 65 – 95 percent water and continue their living processes after being harvested. The post-harvest life-span of the fruit is determined by the rate at which their stored food reserves are used up and by the rate of water los. Once these are exhausted, the fruit decays and dies.
Clearly, each of these need to be managed carefully. One proven way of containing these potentially damaging factors is through using plastic bins.
Achieving the overall objective of providing the highest possible quality fruit to consumers requires careful attention to each phase of production, storage, transportation and distribution. One breakdown in this sequence can adversely impact product quality and profit. Establishment and maintenance of proper storage conditions is a vital link in this chain of events. Seemingly minor differences in room temperature, relative humidity, gas content and uniformity of air distribution can cause significant quality and quantity losses. The image below shows how storage temperatures can be better controlled by allowing air to flow freely through air-vents in plastic bins.
Plastic bins have slots in the floor and sides of bins amounting to 7-1% of the total surface area. Plywood bins have only about 1.5% open area, which greatly limits the amount of airflow through the bins. Cooling air can circulate through plastic bins and around the fruit, greatly increasing the cooling rate. Tests conducted by Patchen et al. (1962) indicate that bins with 8-10% open area col fruit twice as fast as plywood bins with limited ventilation. Similar findings were obtained by Bartsch et al. (1984) and Waelti et al. (192). Increased air flow through the bins results in more even cooling and reduces temperature gradients and temperature differences between various locations in a room. With better ventilated bins, the rows could be stacked close together and still have sufficient cooling air flow through the stacks. Thus, in most rooms, one more row could be added, significantly increasing the room capacity.
Research presented by Hellickson and Baskins (200) documented real-time measurement of fruit cooling rates and efficiencies at 27 locations within regular stacked and tight-stacked rooms filled with both wooden and plastic bins. Further research (Hellickson and Baskins, 203) verified that non-symmetrical bin stacking patterns and open spaces frequently left to allow egress of forklifts adversely affected airflow in the same rooms.
Conventional stacking of fruit bins attempts to maintain an open space of approximately six inches between rows to facilitate airflow past the containers and presumably improve fruit coling. Maintaining this space between rows of wooden bins is seldom accomplished due to wood deflections. Additionally, most wooden bins do not have ventilation slots in their vertical sides. Therefore, the amount of heat transferred from the fruit through the solid sides of a bin is minor compared to cooling induced by air passing over the fruit through the runner space. Unless wooden bins have two-way pallets, space required for forklift movement dictates that some bins must be cross-stacked. Cross-stacked bins are those that the pallet runner space is perpendicular to the majority of bins in a row of bins. Plastic bins are manufactured with two-way pallets which eliminates cross-stacking.
A symmetrical pattern of tight-stacked bins, as is shown below, provides the best possibility for creating uniform air movement throughout the entire room. Minimizing the number of cross-stacked bins in any one stack is prefered.
Physical Injury (Bruising)
Fruit are generally most sensitive to bruise occurrence the day they are picked. The picker is normally the greatest potential cause of bruise damage during hand harvesting operations (picking, bin filing, bin hauling). The picker controls bruising until the fruit is in the bulk bin.
Bin hauling operations will be very damaging if the bulk bins are loose, rough, dirty, or have a thin (springy) bottom. Bins made of rough-sawn hardwood boards can be especially damaging. Rigid, smooth, clean, thick bottom bins cause the least bruise damage. About one-third of all apples in a bin are in contact with the bottom or sidewalls. Using god bins for high quality fruit is the most practical and cost-effective solution.
In a study on damage to Kiwifruit in New Zealand, it was shown that visible damage to kiwifruit from contact to wooden bins was higher compared to plastic bins. Introducing 10mm vents in plastic bins were found to cause least amount of damage to fruit in both ambient and cold storage compression testing.
However, the effect of compression was found to be insignificant compared to the effect of bin material. Therefore, just by changing to a better material, fruit damage can be reduced significantly. It was concluded that, both green and gold fruit are influenced in the same way by 10 mm plastic vents, i.e. 10 mm vented plastic surfaces were found to cause least visible damage to fruit. Vents in wood were found to cause more damage than flat wood surfaces, and it was concluded that this was mainly due to the sharp edges of events leading to severe compression spots. Well rounded edges of vents on plastic surfaces were seen to reduce visible damage.
It was found that the cost of using more expensive plastic bins could be recovered by the saving from reduced fruit rejection. The use of 10mm vented plastic bins would be the most suitable option with shortest payback period of 5.5 seasons.
Wood promotes contamination problems by absorbing chemicals used in orchard and packing house operations. Plastic bins promote much improved sanitation due to their smooth surfaces which do not allow disease-carrying organisms to grow. Bins made of this material do not weather, crack, splinter, warp or become rough with age and are resistant to ultraviolet light. A case in point is the instance of False Codling Moth, which pose a real threat to fruit in storage. A major challenge in false codling moth management is the reintroduction of moths in empty bins containing overwintering (or diapausing) larvae. The scientific literature shows that as many as twelve false codling moth adults can emerge from a single wooden bin. If diapausing codling moth larvae could be eliminated from these containers, then control strategies would be more effective. The decline in the use of post harvest chemicals in the industry has made it more challenging to combat postharvest diseases. Sanitation is therefore paramount and made much easier through the use of Plastic Bins.
Additional factors to consider in bin selection:
Plastic bins are significantly lighter than wooden bins. As long as the bin’s strength and capacity are not sacrificed, this lighter weight contributes to greater mobility of the bins by the pickers and also directly allows more fruit to be transported by truck than for a comparable haul of wooden bins. The uniformity afforded by plastic bins means that they all weigh the same. This means that the growers, who are often paid for the grade and weight of the fruit brought to the warehouse, can more accurately determine the actual weight of the fruit delivered to the warehouse. In addition, some of the storage warehouses weigh the bins before going into storage and again upon removal. Having plastic bins that do not absorb moisture means that the exact weight loss of the fruit while in storage can be determined. Research on the weight loss of fruit in storage revealed that rapid absorption of moisture by dry wooden bins during the early storage season reduces the relative humidity of the storage air which in turn causes more weight loss of the stored fruit (Waelti et al., 1989).
One of the major benefits of polypropylene (PP) Jumbo Bins is the lack of maintenance required to keep them in good condition, as compared with wood bins which are subject to cracking and warping and require constant, expensive repairs. High pressure moulded PP is a tough, resilient material that withstands a great deal of use, provided that they are not abused. Fet on the Jumbo Bins are replaceable. In the event of severe damage or extreme wear, the foot can be replaced either at the factory or by the user. Most wooden bins lack a bin interlocking feature that would promote stability when the bins are stacked. Dry wooden bins also create fire hazards in bin storage areas.
A very expensive part of fruit production is transport. Wooden bins are significantly heavier than plastic bins, thus adding to the fuel expenses of the producers. It has been proven that the use of plastic jumbo bins instead of traditional wooden bins can generate significant financial benefits for the agricultural industry.
A study conducted by MPACT for a fruit farm in the Grabouw-Elgin area, in the Western Cape, indicated total cost savings of R138.69 a bin each year when switching from traditional wooden bins to Mpact's Jumbo Bins, with a payback period of three years was achieved. Similarly, Pieter Nortje, Sitrusrand Estate (350 ha under citrus and an own pack house) in the Sundays River Valley, Eastern Cape achieved financial benefits by using plastic Jumbo Bins were ± R10 per bin for the season.
Pieter’s findings were as follows:
- Almost 10% recovery of drenching water, 50% savings on chemical cost of ± R5.0 per bin turn.
- More even de-greening (ripening)
- No broken bins at the end of the season (saving of R15 per bin per season). - Far less damage to fruit; saving of ± R1.20 per bin turn
- Easier to handle due to increased forklift entry and also interlocking fet
- Increased volume of ± 5% in Jumbo bin over wooden bin.
- Savings of R12.0 per bin per season on de-greening costs.
- No change to bin trolleys due to similar external dimensions of wooden bins.
Wooden Bins vs Plastic Bins
MPACT Jumbo Bins
MPCSA manufactures Jumbo Bins, through a sophisticated high pressure injection moulding process, using impact-modified polypropylene that is fully recyclable and UV-stabilised. This produces a smooth, non-porous surface that is easy to clean and eliminates the HACCP problems usually associated with wooden bins.
The superior inbuilt ventilation reduces cooling time and saves energy The bins are constructed with double walled corners and centre posts and come in either solid or vented options. The later having 804 air vents with 8mm openings and rounded inside surfaces. Two hand holds ensure secure lifting and the fot design enable positive interlocking with two fet. A patented 126mm slide entry facilitates easy forklift aces. The following stacking weights can be achieved:
- Cold Storage on level ground 4700 kg
- Storage on ground level below 35C 3800 kg (up to a month)
- Storage on ground level above 35C 3400 kg (more than a month)
It has been shown that both wooden and plastic bins have been used for more than 50 years in the agricultural industry. Fruit growers are very aware of the impact of especially 4 factors on their produce postharvest; temperature, humidity, bruising and diseases.
Research and industry experience confirms that plastic bins are far superior to wooden bins in how it allows the temperature of storage facilities to be better controlled and also in keeping the fruit ventilated through its optimally designed air vents. Moisture control is better managed by plastic containers since it does not absorb any moisture from the fruit, as wooden bins do. The smooth surfaces of plastic bins are far gentler on the skin of fruit, thus minimising bruising in comparison to the harsher surfaces of wooden bins. The likelihood of contamination and disease has also been found to be far greater with wooden bins, since it cannot be washed and cleaned as efficiently or effectively as plastic containers.
High pressure injection-moulded Jumbo Bins have been designed specifically to overcome the many shortcomings of wood bins and other forms of previously available plastic bins, such as those made from low pressure mouldings, which includes rotationally cast bins and structural foam bins. Being moulded from Polypropylene, these bins are ideal for the harvesting, processing and storage of fruit, vegetables and other types of agricultural products. Al Jumbo Bins are manufactured from FDA (Food and Drug Administration) regulated food approved materials.
These next generation Polypropylene bins represent the cutting-edge of design, engineering and material advances within the packaging industry as it continues to drive efficiency through innovation.