POST-HARVEST FOOD LOSSES

Today, one of the main global challenges is how to ensure food security for a world growing population whilst ensuring long-term sustainable development. According to the FAO, food production will need to grow by 70% to feed the world population which will reach 9 billion by 2050. This has led to the implementation of a series of programs designed by developmental agencies to curb food insecurity. Despite this, the number of food-insecure communities remains acceptably high.

Each year worldwide, massive quantities of food are lost due to spoilage and infestations on the journey to consumers. In some African, Caribbean, and Pacific countries, where tropical weather and poorly developed infrastructure contribute to the problem, wastage can regularly be as high as 40-50%.

Postharvest food loss can be defined as the degradation in both quantity and quality of food production from harvest to consumption. Food losses can be quantitative, as measured by decreased weight or volume, or can be qualitative, such as reduced nutrient value and unwanted changes to taste, color, and texture. The qualitative loss can occur due to the incidence of insect pests, mites, rodents, and birds, or from handling, physical changes or chemical changes in fat, carbohydrates, and protein, and by contamination of pesticide residues, insect fragments, or excreta of rodents and birds and their dead bodies. When this qualitative deterioration makes food unfit for human consumption and is rejected, this contributes to food losses

Factors Responsible for Post-Harvest Losses

Postharvest losses vary greatly among commodities and production areas and seasons. As a product moves in the postharvest chain, Post-Harvest Losses may occur from a number of causes, such as improper handling or biodeterioration by microorganisms, insects, rodents or birds. Factors responsible for post-harvest losses can be grouped into external and internal factors.

Internal factors involve factors that occur at all stages of the supply chain. They include

1. Harvesting: loss is caused majorly by the use of improper harvesting methods such as rough handling, untimely harvest and inappropriate design tools
2. Transportation: losses arise due to poor infrastructure such as roads, lack of refrigerated transports and poor transport systems
3. Storage: losses in this category arise from the lack of proper storage facilities and poor condition of existing storage facilities
4. Biological: Biological causes of deterioration include respiration rate, ethylene production and action, rates of compositional changes. The rate of biological deterioration depends on several environmental factors, including temperature, relative humidity, air velocity, and atmospheric composition

External factors are factors that occur outside the supply chain. They include temperature, humidity, and time

Fig 1: Stages of post-harvest food losses

Strategies for Reducing Post-Harvest Losses

Management of Post-Harvest Losses

There are specific control measures by which, the post-harvest losses can be controlled by the following steps:

• Harvesting of crops should be done at the correct maturity date.
• Water which is used for the irrigation purpose must not be too cold, as for the seed germination there should be milder temperature otherwise, there may occur spoilage like soft rot and other crop diseases.
• Food products with mechanical injury should be discarded early as they can favor the entry of pathogenic microorganisms. Harvesting should be done at cooler temperatures for the perishable products which are then directly transferred to the storage areas.
• The threshing of grains should be handled properly.
• The grains should be dried completely before transportation to the storage areas.
• Storage areas should be highly sanitized and there should be proper ventilation and cleaning.
• The packaging of the product must obey the quality standards in accordance with the shape, weight, nutritional value, etc.
• Transportation time should be reduced as much as possible to reduce wastage along the way.

Read more Urgent Need to Address the Food Security Implications of COVID-19 on Nigeria – Agriculture Nigeria

Food loss and waste | Nutrition | Food and Agriculture Organization of the United Nations (fao.org)

Written by Jeffrey Alahira