RADA DIARIES: Post-harvest management of fresh produce
There are two main functions of post-harvest management:
1. To maintain the good quality of the harvested produce for the market.
2. To reduce the level of losses in weight and quality after harvest so that the shelf/storage life of the produce is extended.
Estimates of post-harvest losses from the field to the market in the following types of produce are as follows:
Leafy vegetables - 50%
Green peas/beans - 30-50%
Fruits - 20-40%
Root crops - 10-20%
Dried products - 5-10%
The level of loss is related to the part of the plant the product represents and therefore, its life- sustaining (physiological) functions that continue after harvest.
Causes of Post Harvest Losses
- Improper harvesting
- Poor handling of the produce from the field through to the market place
- Inappropriate container and use of packaging material
- Poor storage conditions
- Poor transportation and distribution system
- Lack of adequate and appropriate storage facilities
The golden rule of post-harvest management is: "QUALITY CANNOT BE IMPROVED AFTER HARVEST BUT MAINTAINED"
Therefore, only good quality produce must be prepared for market.
Poor quality produce will have a short post-harvest life.
However, the quality, condition and the ability to market fresh produce can be greatly improved by the farmer carrying out proper cultural practices.
- Select appropriate field site.
- Use improved seeds.
- Use seed trays to sow seeds as this saves on expensive seeds and improves germination potential.
- Plant in rows as it is easier to tend and harvest with minimum damage to crops.
- Use cultural practices that will reduce the incidence of disease/pests e.g. crop rotation, time of planting etc.
- Use the type and correct quantity of chemicals recommended for plant protection.
Proper post-harvest management practices
Produce must be harvested without any form of damage and under certain conditions in order to maintain its good quality and prevent spoilage.
Factors to consider:
a) Maturity of the produce
This speaks to the ideal condition for consumption.
Features used to judge the best quality produce include: shape, colour, texture, smell and resonance (sound when tapped); widening of segments (breadfruits, soursop); and drying of the aerial part of the plant (yam, dasheen, onion). Immature produce has a short post-harvest life.
b) Time of day to reap
- All fresh produce must be reaped in the cool of the day to reduce excessive moisture loss and wilting.
- Most crops are freshest and turgid early in the morning.
- Harvesting in the middle of the day should be avoided.
- Night reaping is expensive.
- Produce should not be harvested wet with dew or early-morning rain as when packed, this can lead to spoilage.
c) Harvesting tools and methods
The use of proper tools will prevent unnecessary injury to the produce being harvested.
It is recommended by the Rural Agriculture Development Authority (RADA) that the use of picking poles with bag be employed or climbing and picking by hand to prevent fruits from falling to the ground.
Use of short, sharp knives for cutting stems and trimming in the field is recommended. Outer protective leaves of some types should be left to protect the product through to market.
Root tubers and bulbs
These can be pulled out of the ground if the soil is loose, digging sticks may be used to remove the soil, or a fork being placed far from the root to loosen the soil and lever the tuber up out of the soil.
d) Field handling
Selection and grading:
- The produce must be sorted and graded based on its market quality and the market source.
- They are usually separated into two or three grades.
- The best quality is grade one, those with defects are placed in grade two and the poorest quality placed in grade three.
- Grading assists with pricing as grade-one produce receives the highest price when compared with grade three.
- The quality/grade needed by the market must be determined before sale.
Farm produce are packaged for four main reasons:
- To protect the produce against rough handling during loading and unloading and transport
- To contain the produce as an efficient unit that is easy to handle and that can be marketed as a unit
- To communicate with the buyer by way of a label, thereby advertising and marketing the product via a trade mark or a trade name
- To market the produce, as the package will improve its presentation to the buyer and provide a standard package that will lead to efficiency in the market place
However, the type of packaging used can account for 15 to 20 per cent of post harvest loss in fresh produce.
Read more post-harvest management techniques in the next edition of The Agro Gleaner.
Further information can be had from the Rural Agricultural Development Authority (RADA) by calling 1-888-ASK-RADA or by logging on to www.rada.gov.jm.
Information for the RADA Diaries is compiled and provided by the RADA Communication and Public Relations Department.