Tips to Reduce Bruising When Harvesting

Fresh-market fruit growers have long been concerned about bruising. Processing fruit growers also have grown concerned because unbruised fruit commands the best prices. The vast majority of bruising in the harvest process falls into two categories: picking bruises associated with rough handling and detrimental impacts, and compression bruises associated with significant vibrations during transport.

Bruising is an ever-present problem. One study showed that bruising of fruit after harvest ranged from 0.6% to 13%, with an average of 7.1%. A study conducted of packingsheds indicated that bruising caused 8.1% of the culls, while another study found bruising to cause only 2.7% of the culls. At the retail level in supermarkets, bruising was found to range from 29% to 78%, averaging 61%.

While bruising is a concern, it must be regarded as a defect that can be controlled through basic management principles. Growers should determine the quality of the product being produced, and then determine the dollar value of defects in the product. Good Management Practices will dictate
that production steps be modified if the cost of correcting the problem is less than the cost incurred by defects in the product.

Damage inflicted on fruit is related to the energy available for bruising and the characteristics of the product. The energy available for bruising is in turn related to:

• The suspension characteristics of the vehicle transporting the fruit;
• The energy input to the system (a function of roughness of the road and vehicle speed); and,
• A third engineering factor involving both the properties and the packaging of fruit.

The damage suffered by fruit is dependent on the number of individual shocks and their severity, and is directly related to the energy absorbed by the fruit. You may think you cannot change the characteristics of the products you deal with, but this is not entirely so. Packers of Golden Delicious have learned that packing apples directly on removal from storage may produce more bruised fruit than if fruit is packed after being held at a relatively low humidity for a few days to create an outer layer of bruise-resistant cells. Reducing the amount of bruising in fruit appears to be attainable by reducing the amount of energy that fruit receives in handling.

Steps To A Proper Harvest

In practical terms, bruising can occur during any of six operations in which fruit is removed from the tree and moved into storage. In several Pennsylvania harvest operations, some of these steps may be combined, but they are discussed here individually to show the complexity of an efficient, high-volume harvest operation. Listed below are seven locations of fruit and the six steps involved in moving the fruit from tree to storage:

• In Step 1 (Fruit on the tree/Harvesting), growers can offer incentives to pickers who pick properly and give disincentives or penalties to those who cause more bruising than the set limit. Offering both rewards and penalties does more to encourage pickers to harvest fruit properly than if either penalties or rewards are used alone. In addition, the use of an active supervision system for picking crews can be helpful. Major bruise-reducing practices in Washington State include the use of three-legged aluminum stepladders. Growers do not allow pickers to set straight ladders into trees because they find the resulting damage (bruising and dropped fruits) unacceptable. Another practice is to use bubble liners in bins to absorb energy and vibrations for cultivars such as Golden Delicious and other high-value crops, such as bagged Fuji.

• Step 2 involves moving the fruit within the orchard to the end of the rows. This operation is performed by tractors. Some growers prefer the use of low-profile orchard tractors with wide tires. These tires act like springs and can intercept energy to prevent it from transferring to fruit in a bin.

Other orchard tractors, in contrast, have 12- or 16-inch-wide tires on 24- or 28-inch-diameter rims. These tires are normally inflated to be fairly hard and can therefore transmit more energy to the fruit in a bin as the tractor moves over rough terrain. Growers should use tractors equipped with 18.4-by-16.1 orchard tires.

• Step 3 involves moving fruit from the edge of the orchard to a loading area. If the haul distance is short, it may be desirable to combine this step with Step 2. Special straddle vehicles or four-bin trailers may be useful. In some areas the trailers are operated in reverse and are attached to the front of the tractors. Using a multibin conveyance system may be more efficient than hauling bins singly on tractors.

To lessen bruising, all orchard roads should be as smooth as possible to reduce the energy transferred to fruit during transport. Most loading areas should be smooth and paved, if possible, or at the very least covered with gravel. Muddy loading areas add a significant risk of spreading spores and soilborne decay organisms. Organic material and dirt caught in bin runners can defeat sanitation procedures used at the warehouse in storing and packing fruit.

• Step 4 is loading straight trucks or tractor-trailers for further bin movement. When this operation is performed on paved surfaces, using conventional rubber-tired forklifts may maximize efficiency and may be necessary for handling large volumes of fruit.

• Step 5 is trucking the fruit from orchard to storage. Drivers should be instructed to follow the smoothest roads and to travel at reasonable speeds, especially over rough roads. Special trailers with “air-cushioned rides” will absorb more road shock than conventional trailers.

• The final step, Step 6, is moving the fruit from the trailer to the storage itself. In this phase, loading areas should be as smooth as possible and shock-absorbing forklifts should be used on rough loading areas.

Bruising may be looked upon as a profit-reducing phenomenon and a manageable problem. Bruise-producing operations can be corrected for less money than the reduction in profit caused by the bruising. Remember, bruising is usually caused by only a few procedures. Growers may want to evaluate their present practices in view of the ideas presented here.