Agricultural Product Storage Complete Guide

December 15, 2022November 16, 2023 Agric4Profits

Storage means the phase of the post-harvest system during which the products are kept in such a way as to guarantee food security other than during periods of agricultural production.

The main objectives of storage can be summed up as follows:

At the food level, to permit deferred use (on an annual and multi-annual basis) of the agricultural products harvested;

At the agricultural level, to ensure availability of seeds for the crop cycles to come;

At the agro-industrial level, to guarantee regular and continuous supplies of raw materials for processing industries;

At the marketing level, to balance the supply and demand of agricultural products, thereby stabilizing market prices.

In order to attain these general objectives, it is obviously necessary to adopt measures aimed at preserving the quality and quantity of the stored products over time.

Influences of Environmental Factors

To conserve the quality of products over long-term storage, degradation processes must be slowed down or even stopped.

Degradation of grains during storage depends principally on a combination of three factors:

Temperature,
Moisture,
Oxygen content.

During storage, as during other phases of the post-harvest system, the combined effects of these three factors can sometimes cause severe losses.

Temperature and Moisture

Temperature and moisture are determining factors in accelerating or delaying the complex phenomena of the biochemical transformation (especially the “breathing” of the grain) that are at the origin of grain degradation.

Furthermore, they have a direct influence on the speed of development of insects and microorganisms (moulds, yeasts and bacteria), and on the premature and unseasonal germination of grain.

In the general diagram of conservation designed by Burges and Burrel, the relationship between temperature and moisture content is established in order to determine the area of influence of certain important degradation phenomena, such as: the development of insects and moulds, and the germination of grain.

It is easy to observe that the higher the temperature, the lower must be the moisture of the grain in order to ensure good conservation of the products.

In view of their influence on the speed of development of these degradation phenomena, the temperature and moisture content of the grain condition the maximal duration of storage.

Duration of Warehousing (in days)

	TEMPERATURE
MOISTURE	5°C	10°C	15°C	20°C	25°C	30°C
13%				180	115	90
14%			160	100	50	30
16%		130	50	30	20	8
17%		65	35	22	12	5
18%	130	40	25	17	8	2
19%	70	30	17	12	5	0
20%	45	22	15	8
21%	30	17	11	7
22%	23	3	8	6
23%	17	10	7	5
24%	13	8	4	4
25%	10	8	6	3

As an example, the preceding table shows the recommended durations of warehousing, according to the temperature and moisture content of the grain.

The temperature depends not only on climatic conditions but also on the biochemical changes that are produced inside a grain mass, provoking undesirable natural heating of the stored products.

As for the moisture content of the stored grain, it depends on the relative humidity of the air, as shown in the air-grain equilibrium curves.

With a relative air humidity below 65-70 percent, many grain-degradation phenomena are slowed down, if not completely blocked.

In this sense, the “safeguard” moisture content is defined as that corresponding to an equilibrium with the air at 65-70 percent relative humidity.

The following table shows the moisture content recommended for long-term storage in hot regions of various sorts of grain.

GRAIN	MOISTURE	GRAIN	MOISTURE
	Rice	13.0%	Wheat	13.0%
	Maize	13.0%	Millet	16.0%
	Sorghum	12.5 %	Coffee	13.0%
	Beans	15.0%	Cocoa	7.0%
	Groundnut	7.0 %	Copra	7.0 %

Oxygen Content

Like grain, micro-organisms and insects are living organisms that need oxygen.

Storage of grain in places that are low in oxygen causes the death of insects, cessation of development of micro-organisms, and blockage, or slowing down, of the biochemical phenomena of grain degradation. This favours the conservation of grain, but may affect its germinating power.

Agents Causing Deterioration of Stored Grain

Agricultural Product Storage Complete Guide

The principal enemies of stored grain are micro-organisms, insects and rodents.

Micro-organisms

Micro-organisms (moulds, yeasts, bacteria) are biological agents present in the soil which, when transported by air or water, can contaminate products before, during and after the harvest.

Their presence and growth cause severe changes in the nutritive value and the organoleptic features of grain (taste, smell, aspect).

Furthermore, they are responsible for the alteration of important germinative properties of seeds (vigour and capacity to germinate) and, in the case of moulds, for the potential formation of dangerous poisons (mycotoxins).

Impurities, and cracked or broken grains, foster the development of micro-organisms.

Furthermore, temperature and humidity have a determining influence on the growth rate of these degradation agents.

It has been observed that micro-organisms develop at temperatures between -8°C and +80°C, when the relative humidity of the air is over 65 percent.

On the contrary, atmospheres that are low in oxygen help check the development of these degradation agents.

Insects

Insect infestations can occur either in the field, before the harvest, or in the places where products are stored.

In some cases, these infestations are difficult to discern with the naked eye, since the damage is provoked by the larvae developing inside the grain.

Read Also : Definition and Scope of Agribusiness

The insects most likely to infest stored products belong to the following families:

Coleoptera (damage by larvae and adult insects);
Lepidoptera (damage only by larvae).

Insects can be responsible for significant losses of product. Furthermore, their biological activity (waste production, respiration, etc.) compromises the quality and commercial value of the stored grain and fosters the development of micro-organisms.

Insects can live and reproduce at temperatures between +15°C and +35ºC.

On the contrary, low humidity slows or even stops their development, and a low supply of oxygen rapidly kills them.

Rodents

Rodents invade and multiply in or near storage places, where they can find an abundance of food.

They cause serious damage not only to stored products but also to packaging and even to storage buildings.

The principal rodents, those most common and likely to attack stored products, belong to the following species:

Black rat, also called roof rat (Rattus rattus),
Brown or Norway rat, also called sewer rat (Rattus norvegicus),
Mouse (Mus musculus).

Prolonged attacks by these pests inevitably results in serious quantitative losses of stored products.

To these losses must be added those arising from the decrease in quality of the foodstuffs, caused by the filth (excrement, secretions) rodents leave behind in the stored products.

This contamination is as important from the marketing standpoint as it is for hygiene and health. Indeed, rodents are often the vectors of serious diseases (rabies, leptospirosis).

Storage Methods

There are basically two methods of storage: in bags and in bulk.

Bags can be stored either in the open air or in warehouses; bulk grain is stored in bins or silos of various capacities.

The choice between these methods and the degree of technological sophistication of the storage buildings depend on many technical, economic and socio-cultural considerations.

The traditional storage systems used by small farmers must also be mentioned. With their use of artisanal construction techniques and local materials, these are the systems that prevail in the rural communities of many developing countries.

As post-harvest losses are still a major issue for farmers, lack of electricity and poverty, processing of perishable agricultural produce becomes a very big problem. As population increases, there is need to increase food production without much effort on how what has been produced in excess are stored.

Locally constructed Evaporative coolers are not very expensive to produce and can be used for the preservation of vegetables.

When water evaporates from the surface of a body, that surface becomes much cooler because it requires heat to change the liquid into vapour. Evaporative cooling, therefore, works by evaporating water into air-steam.

The chilling effect that is felt when you come out of a swimming pool and a breeze blows across your body best illustrate this principle (evaporative cooling). The more moisture that is present in the air, the less the chilling effect because the less the evaporation of water.

Also, the less moisture that is present in the air, the more the chilling effect because the more the evaporation of water from the surface of the body (Liberty et al., 2013).

In summary, the main objectives of storage can be summed up as follows:

At the food level, to permit deferred use (on an annual and multi-annual basis) of the agricultural products harvested;

At the agricultural level, to ensure availability of seeds for the crop cycles to come;

At the agro-industrial level, to guarantee regular and continuous supplies of raw materials for processing industries;

At the marketing level, to balance the supply and demand of agricultural products, thereby stabilizing market prices.

It educates youths on the impact and opportunity in the Practical and agro-business.

It also exposes them to vast store of knowledge available for anyone contemplating owing or managing a farm.

This practical aim at promoting sustainable agricultural management for economic development.

It seeks to support local food processing, in-other to improve local knowledge on agricultural mechanization.

The practical seeks to aid food security, this is because food will betage and spoilage can be cut- down through processing.

Looking at the amount of food produced yearly, this practical on processing will aid in conservation and re-organisation of any agricultural produce, while contributing in the development and promotion of agricultural activities.

If greater percentage of our agricultural produce are processed then, importation of many other foreign processed food will be minimized.

Since climate change is one of the greatest challenges to our food crop production, processing will aid in adaptation and mitigation, creating new ways in which our food crop can be properly managed.

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Agricultural Product Storage Complete Guide