Post-Harvest Handling Technology

Post-Harvest Handling Technology

• Fresh produce continues living processes after harvest, containing high water content, respiring, generating heat, and subject to desiccation and mechanical damage
• Storage period and shelf-life depend on the use of stored food reserves and transpiration rate
• Post-harvest losses are the loss of harvested food before it reaches the consumer.
• Post-harvest losses are a major concern in developing countries, often reaching up to 40% of crops due to inadequate infrastructure (e.g., refrigeration) for storage and transportation.

Introduction-Rationale

• In a globalized world, actions impact other people and the environment.
• Food production and consumption contribute to environmental impact, with significant post-harvest food loss
• Post-harvest loss occurs after harvest and results in spoilage, pests, and poor handling.

Primary Causes of Losses

• Environmental conditions: temperature and humidity
• Mechanical issues: poor handling, storage, lack of supporting tools
• Microbial action: bacteria or fungi effects

Secondary Causes of Losses

• Long shipping and distribution
• Insufficient storage facilities and management
• Incomplete drying before threshing
• Poor harvesting handling process
• Complex market and regulatory distribution

Post-Harvest Management

• The main technique is controlling the storage environment and handling conditions, with temperature control being crucial
• Physiological disorders arise from adverse conditions (pre/post-harvest) or mineral imbalances during growth, affecting edible produce handling and storage
• Post-harvest management (PHM) includes processes after harvest: cooling, cleaning, sorting, and packing. PHM treatments improve shelf life and quality.

Postharvest Technology

• The goal is to create cost-effective methods to limit produce deterioration between harvest and end-use, ensuring high eating quality and maximum market value.

How To Reduce Post Harvest Losses

• Improve storage and shipping practices: High temperatures are a leading cause of degradation; using refrigerated storage and cooling systems in developing countries is essential. Controlling temperature is crucial.
• Enhance harvesting standards: Packinghouse standards, harvest procedures, containers, and equipment quality impact post-harvest losses and quality of produce. Setting an optimal harvest period is critical.
• Do clean and proper sorting: Proper sorting and grading, combined with adequate packing and storage improves shelf life and quality, reduces losses, and lowers marketing costs. Sorting distinguishes between excellent and poor quality produce.
• Handle crops softly and delicately: Avoid mechanical damage (bruising and breakage), which creates entry points for pests and raises physiological losses.

Pre-harvest factors in Produce Marketing

• The overall quality of produce before harvest significantly affects its potential market value.
• Market factors affecting farmers' decisions include potential buyers, quality requirements (size, shape, ripeness, appearance, perishability), and pricing limitations.
• Pre-harvest production practices, such as water supply, soil fertility use of fertilizers, cultivation practices, and agricultural chemicals (pesticides), influence post-harvest returns in quality and quantity.

Perishability and Produce Losses

• Fruits, vegetables, and root crops are living tissues with high water content (65-95%) that continue living after harvest, affecting their lifespan.
• Post-harvest losses are caused by physiological deterioration (normal changes due to high/low temperature, humidity, physical injury, or contamination), mechanical damage (physical injury from careless handling), and diseases and pests.

Physiological Deterioration

• Increased loss rate due to normal physiological changes caused by conditions impacting produce (temperature, humidity, etc.) and various environmental/physical factors.
• This may cause flavor changes, failure to ripen, other changes in produce's quality, rendering it unusable.

Mechanical Damage (Physical Injury)

• Careless handling causes internal bruising, leading to abnormal physiological damage, splitting, skin breaks, and increased water loss
• Skin breaks are entry points for infection, leading to decay

Diseases and Pests

• Fresh produce can be infected before or after harvest by various air, soil, and water-borne diseases.
• Some diseases penetrate unbroken skin, causing damage.
• Others require injury to cause infection potentially leading to significant fresh produce loss.

Types of Fresh Produce

• Commoditized fresh produce (fruit, vegetables, root crops) are a wide variety of plant parts from various plant families
• Convenient terms for horticultural and domestic purposes
• Categorized by plant parts (roots/tubers, edible flowers, vegetative growth, and reproductive structures) based on characteristics that affect handling and storage.

The post-harvest physiology of fresh produce

• Green plants use sunlight to create sugars (photosynthesis) by combining carbon dioxide from air and water from the soil via roots
• Sugars are often stored as starch in various parts.
• Starch and sugars provide energy for growth and reproduction.

Respiration

• Plants take in oxygen and release carbon dioxide (respiration).
• This process produces energy (heat) throughout the plant's life cycle from the field until harvest.
• Respiration continues after harvest; stopping this process damages produce.
• Produce uses up its stored carbohydrate/sugar reserves, leading to decay when these reserves are exhausted.

Effect of air supply on respiration

• Respiration of produce depends on a good air supply.
• Restricted air supply causes fermentation, creating bad flavors, and accelerating the aging process.
• Carbon dioxide accumulates, negatively affecting quality.

Transpiration (loss of water)

• Most fresh produce has 65-95% water and constantly loses water vapor during harvesting and post-harvest
• Produce wilts significantly impacting usability and shelf-life after a certain water loss threshold.
• Keeping a moist environment is crucial to minimizing water loss, and controlling air movement can be an effective method of mitigating water loss.