Chapter 4: Perform sub-tropical fruits post-harvest practices

Sub-tropical fruits form a significant part of Kenya's horticultural sector, contributing to both local consumption and export revenue. Ensuring the quality and quantity of these fruits after harvest is essential to maximize their market value and reduce post-harvest losses. This chapter focuses on the analysis of sub-tropical fruits in terms of quality and quantity, equipping horticulture professionals with the skills to assess produce effectively and make informed decisions that enhance profitability and consumer satisfaction.

4.1 Tools and equipment for post-harvest practices

Post-harvest practices are carried out with a set of tools and equipment that keeps fruit clean, cool, undamaged and correctly graded between the orchard and the buyer. A grower or packhouse that has the right equipment, in clean working order, is likely to lose less fruit and to earn better prices. Before looking at the equipment, this topic introduces the main terms of post-harvest handling, the characteristics of sub-tropical fruits that make careful handling necessary and the advantages of handling fruit well.

Introduction

Post-harvest handling begins when the fruit is picked and ends when it is eaten or processed. Everything done in between, from transport and washing to storage, aims to keep quality high and losses low.

Definition of terms - post-harvest handling

• Post-harvest handling: All the activities carried out on fruit after harvest to keep its quality: collecting, transport, cleaning, sorting, grading, packing, storage and marketing.
• Maturity: The stage at which the fruit has finished growing and can ripen properly after harvest.
• Ripening: The changes in colour, softness, sugar, acid and aroma that make the fruit ready to eat.
• Respiration: The process by which harvested fruit keeps breathing, using up its stored sugars and giving off heat, water and carbon dioxide. Fast respiration shortens shelf life.
• Ethylene: A natural gas given off by ripening fruit that speeds up the ripening of nearby fruit.
• Shelf life: The length of time fruit remains good to eat or sell under given conditions.
• Post-harvest loss: Fruit lost between harvest and the consumer through damage, rotting, shrivelling or rejection.
• Chilling injury: Damage to fruit from storage at a temperature that is too low for it, although above freezing.
• Cold chain: An unbroken series of cool conditions from the packhouse to the buyer.

Characteristics of sub-tropical fruits

• Perishable: The fruits have a high water content and a thin or soft skin, and they spoil within days or weeks.
• Continue to live after harvest: They respire and lose water, so they shrivel and soften.
• Ripening behaviour: Avocado, mango, guava, pawpaw and passion fruit continue to ripen after harvest, and ripen faster when they are warm or exposed to ethylene. Citrus, lime and strawberry do not ripen further once picked, so they must be picked ripe.
• Easily damaged: Bruises, cuts and rubbing marks become rots, and mango sap burns the skin.
• Sensitive to temperature: They keep better cool, but many are damaged by temperatures that are too low.
• Seasonal: A large harvest comes at once, and prices fall in the glut, so storage and processing matter.
• Variable in size and quality: The fruit on one tree differs in maturity and size, so sorting and grading are needed.

Advantages of post-harvest sub-tropical fruits handling

• Reduces losses, so more of the harvest reaches buyers.
• Keeps the colour, flavour and firmness that buyers pay for.
• Extends shelf life, giving time to transport fruit and wait for good prices.
• Raises income, since graded and well-packed fruit gets a higher price than ungraded fruit.
• Opens markets such as supermarkets, processors and exporters, which demand set standards.
• Improves food safety, as clean handling reduces contamination.
• Provides work in the packhouse, in transport and in processing.
• Reduces waste, and so the cost and effort of disposal.

Tools and equipment for post-harvest handling

Care of equipment: wash and sanitise tools and surfaces at the end of each day, keep scales and instruments accurate by checking them regularly, repair broken crates and tables, and store everything clean and dry. Use equipment only for fruit, and keep chemicals, fuel and tools for other tasks apart.

Chapter Summary

This chapter explored the analysis of sub-tropical fruits quality and quantity, emphasizing the importance of accurate assessment to ensure market readiness and consumer satisfaction. It detailed essential post-harvest practices that maintain fruit freshness and extend shelf life through proper handling, storage, and transportation methods. The discussion then shifted to marketing techniques tailored to sub-tropical fruits, highlighting strategies that enhance product visibility and competitiveness in diverse markets. Finally, the chapter addressed waste management regulations and the handling of waste materials generated during post-harvest operations, underscoring compliance with environmental standards and sustainable practices. Together, these topics provide a comprehensive understanding of how to manage sub-tropical fruits effectively from harvest to market while minimizing losses and environmental impact.