🌷 Factors Responsible for Post-Harvest Losses

Post-harvest loss is rarely caused by one single factor. It usually develops through a chain of biochemical, physical, biological, and management failures, which is why post-harvest handling must be studied as a system rather than an isolated step.

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Primary Causes of Loss

Primary causes directly affect food quality and quantity.

Enzymic changes

Endogenous enzymes drive ripening and senescence and may cause undesirable softening, browning, and spoilage. Control measures include temperature, pH, water activity, and enzyme inhibitors.

Chemical changes

Lipid oxidation and non-enzymatic browning reduce sensory quality. Light, oxygen, high temperature, catalytic metals, and unsuitable water activity accelerate deterioration.

Nutritional losses are also promoted by exposure to light, oxygen, and heat.

Physical changes

Moisture absorption or moisture loss due to poor packaging barrier causes caking, softening, and textural defects.

Biological changes

Bacteria, yeasts, and moulds spoil perishable commodities rapidly under favorable conditions. Insect pests and rodents further increase contamination and losses.

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Secondary Causes of Loss

Secondary causes create conditions that trigger primary losses.

These include poor harvesting and handling skills, inadequate packaging, weak storage infrastructure, poor transport, lack of refrigeration, weak drying systems, and inefficient marketing and management.

Large seasonal gluts can overload handling capacity and increase wastage.

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Major Sites Where Losses Occur

Losses can occur at every stage:

• Harvest
• Preparation and cleaning
• Preservation
• Processing
• Storage
• Transportation
• Marketing and distribution

Each stage must be optimized to reduce cumulative loss.

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Summary Cheat Sheet

Quick Recall Points

• Post-harvest losses arise from enzymic, chemical, physical, biological, and management-related causes.
• Primary causes directly damage produce; secondary causes create conditions that allow those losses to increase.
• Losses can begin at harvest and continue through processing, storage, transport, and marketing.
• Good control requires both scientific handling and system-level infrastructure.

Exam Traps

• Do not separate biology from logistics too sharply; both interact in real post-harvest loss.
• Mechanical injury often looks minor at first but later accelerates decay and water loss.
• Secondary causes are not “less important”; they often determine the scale of primary damage.

References

2 sources • [1] [2]

[1]

FAO: Prevention of Post-Harvest Food Losses

Reference

[2]

UC Davis Postharvest Technology Center

Reference