INJURIESINJURIES

All horticultural products are sensitive to various All horticultural products are sensitive to various injuries after harvest. The extent of type injury will injuries after harvest. The extent of type injury will vary with each product, the variety, the maturity, the vary with each product, the variety, the maturity, the water content, the handling system, the form of water content, the handling system, the form of packaging used and the condition of the product. packaging used and the condition of the product. There are four main forms of injury on fresh produce. There are four main forms of injury on fresh produce. They are :They are : Mechanical injuryMechanical injury Pathological injuryPathological injury Insect and rodent injuryInsect and rodent injury Physiological injuryPhysiological injury

Mechanical InjuryMechanical Injury

Mechanical injury reduces the quality and Mechanical injury reduces the quality and saleability of a product through loss of visual saleability of a product through loss of visual appearance, increases the rate of deterioration appearance, increases the rate of deterioration through water loss and increases its through water loss and increases its susceptibility to decay. susceptibility to decay.

There are three types of mechanical injuryThere are three types of mechanical injury ImpactImpact CompressionCompression Vibration Vibration

Impact mechanical injury is caused by dropping a Impact mechanical injury is caused by dropping a product onto another product or a hard surface. product onto another product or a hard surface. Impact injury is often caused by high drop heights in Impact injury is often caused by high drop heights in harvesting and packing line equipment, manual harvesting and packing line equipment, manual handling and poor forklift operation.handling and poor forklift operation.

Compression mechanical injury is caused by trying to Compression mechanical injury is caused by trying to put too much product into a package of specified put too much product into a package of specified volume. volume.

Vibration mechanical injury is also referred to as Vibration mechanical injury is also referred to as transit as this when it is most likely to occur. transit as this when it is most likely to occur.

Pathological InjuryPathological Injury

The method of handling fresh produce after The method of handling fresh produce after harvest will largely determine the extent of harvest will largely determine the extent of decay development postharvest.decay development postharvest.

Postharvest decay of fresh produce is caused Postharvest decay of fresh produce is caused by fungi, bacteria and in a few cases, viruses. by fungi, bacteria and in a few cases, viruses.

Maturity of the product will also influence a Maturity of the product will also influence a product’s susceptibility to decay. product’s susceptibility to decay.

Insect and rodent injuryInsect and rodent injury

Insect and rodent injury reduces the Insect and rodent injury reduces the appearance of horticultural products. appearance of horticultural products.

Aside of from visual damage, the injury will Aside of from visual damage, the injury will also increase the rate of production of also increase the rate of production of endogenous ethylene and provide an entry endogenous ethylene and provide an entry point for decay, both of which will hasten point for decay, both of which will hasten deterioration and shorten shelf-life.deterioration and shorten shelf-life.

Physiological injuryPhysiological injury

The most common causes of physiological injury are The most common causes of physiological injury are incorrect temperature management or a mineral incorrect temperature management or a mineral nutrient deficiency during growth and development.nutrient deficiency during growth and development.

The susceptibility of products to physiological injury The susceptibility of products to physiological injury depends on :depends on : The varietyThe variety The product maturity at harvestThe product maturity at harvest The crop production practicesThe crop production practices The weather conditions present during growthThe weather conditions present during growth The size of the productThe size of the product The harvesting practicesThe harvesting practices

Temperature injuryTemperature injury

Correct temperature management is the single Correct temperature management is the single most important tool in controlling the rate of most important tool in controlling the rate of deterioration of fresh produce. deterioration of fresh produce.

There are three forms of temperature injury :There are three forms of temperature injury : High temperature injuryHigh temperature injury Chilling injuryChilling injury Freezing injuryFreezing injury

High temperature injuryHigh temperature injury At temperatures above 30At temperatures above 30ooC, biochemical activity in C, biochemical activity in

the product may be adversely affectedthe product may be adversely affected If temperatures go above 40If temperatures go above 40ooC, the enzymes start to C, the enzymes start to

become inactivated.become inactivated. Product death will occur in some tissue at Product death will occur in some tissue at

approximately 45approximately 45ooC.C. Under high temperature conditions, color fails to Under high temperature conditions, color fails to

develop properly and often there is a loss of color. develop properly and often there is a loss of color.

Chilling injuryChilling injury Chilling injury is a physiological disorder that Chilling injury is a physiological disorder that

induced by exposing certain products to low, but non-induced by exposing certain products to low, but non-freezing temperature for a certain period. freezing temperature for a certain period.

The extent of any chilling injury will be determined The extent of any chilling injury will be determined by three factors :by three factors : The temperatureThe temperature The duration of the exposureThe duration of the exposure The sensitivity of the product to chilling injuryThe sensitivity of the product to chilling injury

The actual temperature that will cause chilling injury is very The actual temperature that will cause chilling injury is very product specific. For example, pineapples have been shown to product specific. For example, pineapples have been shown to chill at temperatures below 25chill at temperatures below 25ooC.C.

The lower the temperature below the critical chilling The lower the temperature below the critical chilling temperature, the less time it takes for the injury to occur and temperature, the less time it takes for the injury to occur and the more severe it will be. the more severe it will be.

The typical symptoms of chilling injury include :The typical symptoms of chilling injury include : An increased incidence decayAn increased incidence decay Discoloration externally and internallyDiscoloration externally and internally Irregular ripening or failure to ripen altogether Irregular ripening or failure to ripen altogether Textural changesTextural changes Off-flavors and off-odorsOff-flavors and off-odors Reduced nutritive valueReduced nutritive value

Freezing injuryFreezing injury Plant tissue will freeze below 0Plant tissue will freeze below 0ooC. C. Most products freeze between 0Most products freeze between 0ooC and -2C and -2ooC.C. Freezing of water may take place either Freezing of water may take place either

intracellurarly (within the cell) which is usually fatal intracellurarly (within the cell) which is usually fatal or extracellularly (outside of the cell). or extracellularly (outside of the cell).

When a cell’s contents freeze they expand in size, When a cell’s contents freeze they expand in size, rupturing the cell wall. Upon thawing, the product rupturing the cell wall. Upon thawing, the product disintegrates into a “water sack”. disintegrates into a “water sack”.