Egg Technology SS3 Livestock Farming Lesson Note

Introduction: The Egg as a “Package”

An egg is nature’s perfect container. It comes with its own “packaging” (the shell) and is packed with all the nutrients needed to create a life. However, once an egg is laid, it starts to lose quality.

Egg Technology is about two things:

1. Preservation: Stopping the egg from going bad or drying out.
2. Processing: Breaking the egg out of its shell and turning it into something else (like powder or liquid) to make it easier for bakeries and factories to use.

Why do Eggs Spoil?

To preserve an egg, we must understand its enemies:

• Evaporation: The shell has thousands of tiny holes (pores). Over time, water escapes through these holes, and the air cell inside the egg gets bigger.
• Bacteria: If an egg is cracked or kept in a dirty place, germs can crawl through the pores and rot the yolk.
• Temperature: In the Nigerian heat, the “thick” part of the egg white turns into “watery” white very quickly.

Methods of Egg Preservation

If we want eggs to last longer than the usual 2 weeks, we use these methods:

1. Refrigeration (The Best Way)

Keeping eggs at about 4°C to 7°C slows down everything. It keeps the yolk centered and stops bacteria from growing.

• Tip: Always store eggs with the “pointy end” down to keep the air cell stable.

1. Oil Coating

This is a clever trick! We dip the egg in a thin, tasteless mineral oil. The oil plugs up the tiny pores in the shell. This stops water from leaving and stops air/germs from entering.

1. Cold Storage (Water Glassing)

An old-fashioned method where eggs are submerged in a solution of “Sodium Silicate.” This seals the shell completely. This can keep eggs fresh for months without electricity!

Egg Processing: Beyond the Shell

Sometimes, a bakery doesn’t want to crack 5,000 eggs by hand. This is where Processing comes in.

1. Liquid Eggs

Eggs are cracked by machines, filtered, and put into cartons (like milk).

• Pasteurization: Just like milk, liquid eggs are heated briefly to kill germs like Salmonella without “scrambling” the egg.

1. Egg Powder (Drying)

The egg is sprayed into a hot chamber where the water evaporates instantly, leaving a fine yellow powder.

• Why do it? Egg powder doesn’t need a fridge! It can last for a year and is very easy to transport to remote areas.

1. Frozen Eggs

Liquid eggs are mixed with a little salt or sugar (to stop them from getting “rubbery”) and frozen.

Other Egg Products

We also use eggs to create other household items:

• Mayonnaise: Eggs act as the “glue” (emulsifier) that holds oil and vinegar together.
• Egg Shell Meal: Dried and crushed shells are a great source of Calcium for animal feed or garden fertilizer.
• Lysozyme: A special protein in egg whites used in medicine to kill bacteria.

Summary: Fresh vs. Old Eggs

Class Discussion / Practical Activity

1. The Float Test: Bring a bowl of water to class. Put a fresh egg and an old egg inside. Ask the students to explain why the old one behaves differently based on “Evaporation.”
2. Home Experiment: If you don’t have a fridge at home, how can you use “Vegetable Oil” to make your eggs last longer?
3. Critical Thinking: Why would a biscuit factory prefer to buy “Egg Powder” instead of crates of fresh eggs? (Think about storage, transport, and the risk of shells falling into the dough).