Best Practices of Handling Chicken Eggs
The main poultry products marketed in most countries are eggs and poultry meat. The tastes of consumers vary and for the acceptability of these products to the consuming public, prompt disposal is important to avoid deterioration and/or spoilage and to make the enterprise profitable.
It is therefore not only important for farmers to think in terms of production to bridge the protein gap in the country, but the handling of these major products of the industry in terms of processing and marketing is equally important. This involves some technicalities which we will address in this article.
The following are ideal ways of handling eggs:
1. Egg Cleaning
Eggs are a very rich source of animal protein. However, they are a good medium for bacteria and thus can easily become infected and lose their quality if incorrectly handled after being laid.
It is, therefore, important that eggs should be produced in as clean a form as possible to avoid spoilage and avoid the need to wash them which can remove the protective coat from the outside of the egg.
Dirty eggs should be cleaned with abrasive materials in preference to washing. If it is necessary to wash, the best method is by immersion between 33oC and 35oC in temperate climates and 40oC in the tropics.
The immersion time varies with temperature. At lower temperatures immersion time of 10-15 minutes is necessary but at higher temperatures immersion time of 3-5 minutes is adequate. The amount of sanitizer put into the water should be as advised by the manufacturers.
Water used for cleaning should be changed frequently to minimize the risk of contamination and washed eggs should not be stored.
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2. Egg Preservation/Storage
Sometimes, the poultry farmer experiences an egg glut and since eggs can very quickly deteriorate, it is important to know how to preserve them. Egg preservation is to minimize the loss of moisture and carbon dioxide which forms the starting point of deteriorative changes.
The ideal temperature for storage is lower than 13oC which is often impossible in tropical countries. Thus in these countries, the eggs should be kept out of direct sunlight and put in the coolest place possible, and sold by the third day after laying.
Eggs absorb strong odors very quickly and should therefore be stored in places where such odors are absent. Generally, refrigeration rather than evaporative cooling should be preferred in the tropics.
Some methods for preserving eggs are as follows:
The Water Glass Method: This involves dipping eggs in a solution of sodium silicate or water glass. A coating of silica is formed over the shells and their pores are completely closed. By this method, eggs can be stored safely for up to 6 months. About 15 dozen eggs can be preserved in 10 litres of the solution.
The Lime Water Method: This involves dipping eggs in the supernatant liquid (lime water) obtained by adding 1kg of unslaked lime to 20 litres of water in an enamel vessel. Eggs can be preserved this way for nearly six months.
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Oil Protection: Eggs are dipped in warm oil 4-6 hours after lay. The oil temperature should be 11oC higher than that of the egg. The oil should be colorless, tasteless, and odorless e.g. coconut, and groundnut oils.
The oil seals the pores of the shell which prevents evaporation and loss of carbon dioxide, thus it maintains good internal quality and prevents weight loss. Before re-use, the oil is heated to 116oC to kill spoilage bacteria, and it is filtered. Four litres of oil is sufficient for 30 cases of eggs.
Thermostabilization: This is the stabilization of egg quality by heat. Eggs may be thermostabilized by immersing the shell eggs for 15 minutes in water at 54.40oC or 60oC for 3 to 5 minutes. This process helps to pasteurize the eggs (kills bacteria on the egg shell), de-fertilizes the eggs, and stabilizes the egg.
ColdStorage:The temperature of an egg-storage room should be maintained at +0.5oC to -0.5oC and with a relative humidity of 75 to 85%.
Freezing: The freezing of the internal contents of eggs is a common method of preservation, especially in developed countries.
The equipment for freezing liquid eggs consists of a candler, eggs washer, breaking table or machine, churn, scale, tables, and cleaning tanks and racks. The eggs are first candled to detect any possible defects.
Before breaking, eggs should be washed with water at 11oC higher than the temperature of the egg using an odorless, germicidal, colorless, and non-toxic detergent sanitizer.
The yolk and the white may be frozen separately with the addition of 5% glycerine. The egg contents are then frozen in a freezer at a low temperature of about – 41oC. The contents are kept at a low temperature until required for use.
Drying: Egg drying is now being used in place of freezing. The egg contents are dried at a temperature of 160oF and stored under 50oF to convert white, yolk, or the whole egg into a fine powder.
With the present day, low egg production and unsatisfactory marketing facilities, preservation and storing of eggs by freezing and drying may not be of immediate interest to most countries.
3. Egg Grading
Grading is the sorting out of eggs into different categories according to their individual weight, shell shape, and interior quality.
Only eggs with smooth shells and normal shape are sent to market. In most countries where eggs are in short supply, grading is not necessary except if it will guarantee an increased income because grading takes time and costs money.
Based on the quality of eggs and according to size, four classes have been adopted. Grading for internal quality is done by candling while for the weight of an individual egg there are various types of automatic devices on the market. Egg grading according to size is as follows:
Table: Standards for Weight Classification of Shell Eggs
| Size | Weight per Egg (g) |
| Extra large | ≥60 |
| Large | 53 – 69 |
| Medium | 45 – 52 |
| Small | 38 – 44 |
4. Marketing Eggs
In developing countries, where egg production is low, eggs are easily packaged and distributed without any preparation before consumption apart from cooking the product in one way or another.
In some countries, populations will not consume fertilized eggs-whereas in other countries, fertilized eggs are preferred. These preferences should be considered when eggs are being prepared for sale.
To maximize income, an egg farmer must ensure that his maximum supply of eggs coincides with the minimum supply of eggs from local sources. With rapid expansion in the poultry industry, it is very easy to go from a deficit to a surplus supply and if large amounts of capital are put into poultry production, it would be easy for farmers producing these eggs to go bankrupt.
Therefore, a careful assessment of the likely market, the changing market, and changes in other farmers’ levels of production should be put into consideration before committing large capital to develop poultry units.
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