What Is The White Spot On The Yolk Called – What You Didn’t Know Until Now: A Complete Guide

Ever cracked an egg and noticed a small, white spot on the yolk? You might have instinctively wondered if it was something to worry about. This guide will not only answer the question "What is the white spot on the yolk called?" but also delve into its origin, significance, and dispel any myths surrounding it. Prepare to become an egg expert!

Prerequisites:

  • A curious mind

  • Basic understanding of egg anatomy (yolk, white, shell)

    • Tools (Optional):

  • A fresh egg (for observation)

  • Bright light source (for better visibility)

  • Magnifying glass (optional, for detailed observation)

    • Step-by-Step Guide:

    Step 1: Identifying the White Spot

    1. Crack the Egg: Gently crack a fresh egg into a clean bowl or onto a flat plate. Avoid breaking the yolk.
    2. Observe the Yolk: Carefully examine the yolk. Look for a small, whitish spot that is slightly raised. It might appear as a small circle or an irregular shape.
    3. Use Light (Optional): If the spot is difficult to see, position a bright light source behind the egg. This will help illuminate the yolk and make the white spot more visible.
    4. Magnify (Optional): If you have a magnifying glass, use it to get a closer look at the spot's texture and shape.

    Step 2: Understanding the Terminology: The Blastodisc (or Blastoderm)

    This is the crucial step. The white spot you've observed is scientifically known as the blastodisc (if unfertilized) or the blastoderm (if fertilized).

    1. "Blastodisc" Defined: In an unfertilized egg, the white spot is called the blastodisc. It's a small cluster of cells present in all eggs, regardless of whether they are intended for fertilization. This is the female genetic material.
    2. "Blastoderm" Defined: In a fertilized egg, the white spot is called the blastoderm. This is the result of the sperm fertilizing the blastodisc. It contains the genetic material from both the hen and the rooster and has the potential to develop into a chick.

    Step 3: The Origin and Purpose of the Blastodisc/Blastoderm

    Understanding where it comes from and what it *could* become is key.

    1. Origin: The blastodisc/blastoderm originates from the hen's ovary. It's essentially the starting point for potential embryonic development.
    2. Potential for Development (Fertilized Egg): If the egg is fertilized by a rooster, the blastodisc becomes a blastoderm. This fertilized blastoderm contains the complete genetic blueprint required to develop into a chick.
    3. No Development (Unfertilized Egg): In unfertilized eggs (most commercially sold eggs), the blastodisc remains dormant. It will not develop into a chick. These eggs are perfectly safe and nutritious to eat.

    Step 4: Distinguishing Between the Blastodisc/Blastoderm and Other Imperfections

    Sometimes, other things can be mistaken for the blastodisc/blastoderm.

    1. Chalazae: These are the white, rope-like strands that connect the yolk to the egg white. They are *not* the blastodisc/blastoderm. Chalazae are perfectly normal and help anchor the yolk in the center of the egg. They are often more prominent and stringy than the small, spot-like appearance of the blastodisc/blastoderm.
    2. Blood Spots: Occasionally, you might find a small blood spot on the yolk. This is caused by a ruptured blood vessel during egg formation. While not harmful, some people prefer to remove them. Blood spots are typically red or brown, not white, and are distinct from the blastodisc/blastoderm.
    3. Meat Spots: These are small pieces of tissue that sometimes appear in the egg white. They are also harmless and are not related to the blastodisc/blastoderm.

    Step 5: Addressing Common Misconceptions and Myths

    Time to debunk some myths!

    1. Myth: The white spot means the egg is fertilized and will hatch. This is false for commercially sold eggs in most regions. These eggs are typically unfertilized. Even if the egg *were* fertilized, it needs proper incubation (temperature and humidity) to develop.
    2. Myth: The white spot means the egg is old or spoiled. This is incorrect. The presence of a blastodisc/blastoderm is not an indicator of freshness. Use the "sell-by" or "expiration" date on the carton as a more reliable guide.
    3. Myth: The white spot is unhealthy or unsafe to eat. This is completely false. The blastodisc/blastoderm is a natural part of the egg and is perfectly safe to consume.

    Troubleshooting Tips:

  • Can't find the spot? Try using a fresh egg. The blastodisc/blastoderm is more visible in fresher eggs.

  • Still unsure? Compare the spot to images of blastodiscs/blastoderms online. This will help you confirm your identification.

  • Worried about freshness? Perform a float test. Place the egg in a bowl of water. If it sinks and lies flat, it's fresh. If it floats, it's likely old and should be discarded.

Summary:

The small, white spot you might find on an egg yolk is called the blastodisc (in unfertilized eggs) or the blastoderm (in fertilized eggs). It is a natural part of the egg and represents the potential for embryonic development. In commercially sold eggs, this spot is almost always a blastodisc, meaning the egg is unfertilized and will not hatch. The blastodisc/blastoderm is perfectly safe to eat and does not indicate spoilage. By understanding its origin and function, you can confidently crack open eggs and appreciate the fascinating biology contained within! Now you know what that little white spot is all about!