Post-harvest practices in tropical fruit production are critical to preserving the quality, extending shelf life, and maximizing the economic value of harvested fruits. In Kenya, where tropical fruits such as mangoes, pineapples, avocados, and passion fruits contribute significantly to both local consumption and export markets, effective post-harvest management reduces losses caused by spoilage, pests, and mechanical damage. Understanding and implementing best practices from the farm to the consumer ensures that horticulture professionals maintain fruit freshness, nutritional value, and market competitiveness. This chapter explores key post-harvest practices applied in Kenyan tropical fruit production systems.

4.1 Post-harvest practices

Post-harvest practices encompass all the procedures and operations applied to tropical fruits immediately after harvest to maintain their quality and prepare them for marketing and consumption. These practices are essential because tropical fruits are highly perishable, vulnerable to rapid deterioration due to climatic conditions, microbial attack, and physical damage. Kenyan horticulture professionals working in farms, cooperatives, and agribusinesses must adopt appropriate post-harvest handling techniques to reduce losses that otherwise pose major economic challenges.

Cleaning of harvested fruits

Cleaning removes field dirt and reduces the microbial load on the fruit surface before it is stored or marketed. It improves consumer appeal and the price producers obtain. Clean fruit also carries fewer spores into crates and cold rooms, so decay spreads less.

• Removal of soil and debris: Washing fruits with clean water removes dust, soil and some surface residues and contaminants that can accelerate spoilage or cause health risks.
• Reduction of microbial contamination: Cleaning limits fungal and bacterial populations on fruit surfaces, essential for fruits like pineapples and passion fruits prone to fungal decay.
• Water washing with potable water: Gentle rinsing removes dirt without damaging fruits; chlorinated water may be used to reduce microbial load in packing houses.
• Drying after washing: Air drying or using clean cloths prevents water-induced rotting during storage.
• Sanitising equipment and work areas: Maintaining hygiene on tables, tanks and tools reduces contamination risks during handling.

4.1.1 Definition of terms

Post-harvest work has its own vocabulary, and a horticulturist must use it accurately when handling mangoes, avocados, pineapples, passion fruits and other tropical fruits. A packhouse supervisor who says a consignment of mangoes has "field heat" or "high respiration" is describing a specific, measurable condition that decides which action is taken next. The terms below are grouped by what they describe, and later topics in this chapter treat each operation in detail.

Terms describing the fruit and its condition

• Post-harvest: The period and the set of operations from the moment a fruit is separated from the plant until it is eaten or processed. It includes handling, treatment, storage, transport and marketing.
• Tropical fruits: Fruits that grow best in warm, frost-free climates, such as mango, avocado, pineapple, passion fruit, banana and papaya. Most have high water content and thin skins, which makes them delicate.
• Perishability: The tendency of a fresh fruit to spoil quickly. It results from high water content, active metabolism and a skin that offers limited protection against microbes.
• Maturity: The stage of development at which a fruit has grown enough to ripen properly after picking. A mature mango picked from the tree will soften and sweeten, while an immature one will shrivel and stay sour.
• Ripening: The changes that follow maturity: softening, colour change, rising sweetness and development of aroma. Ripe fruit is ready to eat but has a short remaining life.
• Climacteric fruit: A fruit that continues to ripen after harvest, with a surge in respiration and ethylene production. Mango, avocado, banana, papaya and passion fruit are examples.
• Non-climacteric fruit: A fruit that does not become sweeter after harvest and must be picked at full eating quality. Pineapple is an example.
• Respiration: The process in which a living fruit breaks down its sugars using oxygen and releases carbon dioxide, water and heat. A high respiration rate means the fruit is using up its stored reserves quickly and will deteriorate sooner.
• Ethylene: A plant hormone, given off as a gas by ripening fruit, that triggers and speeds up ripening in itself and in fruits nearby. A ripe avocado stored beside unripe ones will hasten their ripening.
• Transpiration: The loss of water vapour from the fruit surface. Excessive transpiration causes shrivelling, weight loss and a dull appearance.
• Field heat: The heat a fruit carries from the orchard at the time of picking. It speeds respiration and decay, so it must be removed soon after harvest.
• Shelf life: The length of time a fruit remains acceptable in appearance, taste and safety under given storage conditions.

Terms describing handling operations

• Harvesting: The removal of mature fruit from the plant by hand or with simple tools. It is the first post-harvest operation and strongly affects all that follows.
• Cleaning: The removal of soil, dust and surface contaminants from harvested fruit, usually with clean water.
• Sorting: Separating fruit that is sound from fruit that is damaged, diseased or unripe, so that only suitable produce moves forward.
• Grading: Classifying sound fruit into classes according to size, colour, shape and freedom from defects, so that each class meets a market specification.
• Packaging: Placing fruit in suitable containers that protect it from damage and contamination and make handling, stacking and labelling easier.
• Cooling: Lowering the temperature of freshly harvested fruit to remove field heat and slow respiration. Pre-cooling is cooling done quickly before storage or transport.
• Freezing: Lowering the temperature of fruit or fruit pulp below its freezing point for long-term preservation.
• Drying: Removing most of the water from fruit, for example mango or pineapple slices, so that microbes cannot grow and the product can be kept for months.
• Storage: Holding fruit under controlled or favourable conditions of temperature, humidity and ventilation until it is sold or processed.
• Cold chain: An unbroken series of cooled handling, storage and transport steps from farm to consumer. A break at any step, such as leaving crates in the sun at a loading bay, shortens shelf life.
• Transportation: The movement of fruit from the farm or packhouse to the market, processor or port, by vehicles that protect it from heat, shocks and contamination.

Terms describing losses, quality and marketing

• Post-harvest loss: Any reduction in the quantity or quality of fruit between harvest and consumption. It may be physical, such as crushed fruit, or in value, such as fruit downgraded because of blemishes.
• Quality: The combined characteristics of a fruit that make it acceptable to buyers, including appearance, firmness, flavour, nutritional value and safety.
• Food safety: Assurance that fruit is free from harmful microbes, chemical residues and physical contaminants when it reaches the consumer.
• Traceability: The ability to follow a consignment back to the farm and forward to the buyer, using labels and records. It makes it possible to find the source of a quality or safety problem.
• Marketing: All activities used to move fruit from producer to buyer, including finding buyers, pricing, promotion and delivery.
• Online marketing: Promoting and selling produce through digital channels such as websites, social media and messaging platforms.
• Influencer marketing: Promotion of a product through people with a following who recommend it to their audience.
• Public relations: The planned effort to build and maintain a good reputation and relationship between a fruit business and its customers, partners and the public.
• Post-harvest waste: Fruit residues and rejected produce, such as peels, damaged fruit and spoiled packaging, that arise during handling and processing.
• Waste management: The collection, treatment, reuse or safe disposal of post-harvest waste so that it does not pollute the environment or attract pests. Examples include composting rejected fruit.

Chapter Summary

This chapter explored the essential post-harvest practices critical for maintaining the quality and extending the shelf life of tropical fruits. It began with an overview of post-harvest practices, emphasizing their role in reducing losses and preserving fruit freshness. Various methods were examined, including cooling, freezing, drying, grading, sorting, packaging, storage, and transportation, each contributing uniquely to fruit preservation and market readiness. The discussion then shifted to marketing techniques, highlighting the growing importance of online marketing, influencer marketing, and public relations in promoting tropical fruits to wider audiences. Finally, the chapter addressed the management of wastes generated during post-harvest handling, underscoring the need for sustainable practices to minimize environmental impact and enhance resource efficiency. Together, these topics provide a comprehensive understanding of the post-harvest handling and marketing processes vital for successful tropical fruit production.