Can an egg with a blood spot be sold?

It depends on the size, the number and where the spot is. Small, few spots in the white and the yolk put the egg in Class B, intended for industrial processing (RIISPOA, art. 226). Dark spots or blood that also reach the white make the egg unfit for human consumption (art. 500, I).

What is the difference between blood on the shell and a blood spot inside the egg?

Blood on the shell is external dirt: it takes the egg out of Class A, which requires a clean shell (RIISPOA, art. 225, I). A spot inside the egg is an internal defect, and its class depends on its size and where it is. The two cases need different methods to be seen.

Can a camera find blood spots inside the egg?

Not inside. The Vigiovo camera analyses the shell and classifies the egg as clean, dirty, cracked or unverified. Spots inside the egg are seen only by candling, which is a mandatory step and comes before the final classification (RIISPOA, art. 223).

Explainer · Defects and grading

Blood spot in an egg: what decides the class?

A blood spot inside the egg is an internal defect. If it is small and there are few spots, in the white and the yolk, the egg is Class B, intended only for industrial processing (RIISPOA, art. 226, II). If dark spots or blood also reach the white, the egg is unfit for human consumption (art. 500, I). A surface camera sees only the shell, so this decision depends on candling.

Updated October 9, 2026 · 4 min read

What is a blood spot inside the egg?

A blood spot inside the egg is an internal defect: the blood lies in the white or the yolk, not on the shell. It usually forms while the egg is being produced in the hen, when a small blood vessel ruptures. For that reason, the spot cannot be seen from the outside of the egg.

Do not confuse it with blood on the shell, which is external dirt and takes the egg out of Class A under the clean-shell requirement (RIISPOA, art. 225, I). Here the problem is inside the egg, and the destination depends on the size of the spot and where it is.

When does a spot put the egg in Class B?

Under the Brazilian rule, Class B includes eggs with small blood spots, few in number, in the white and the yolk (RIISPOA, art. 226, II). These eggs are intended exclusively for industrial processing (art. 226, sole paragraph).

Class B does not mean the egg is unfit. It does not meet the Class A requirements, but it can go to industrial processing. To understand the category as a whole, see Brazil's Category B eggs.

The RIISPOA text does not set a size in millimetres for a spot, nor a maximum number of spots. Judging size and number is a practical call, and the establishment should write down its criterion and apply it the same way on every shift.

When does a spot make the egg unfit for consumption?

An egg is unfit for human consumption, as it is found, when there are dark spots or blood that also reach the white (RIISPOA, art. 500, I). The same article lists other changes to the yolk and white, such as a broken yolk.

The difference is reach. A small, rare spot that stays in the yolk or the white, without reaching the rest of the egg, goes to Class B. A spot that reaches the white changes the destination. That is why candling must show the spot and let the grader see whether it reaches the white.

Destination of a blood spot inside the egg
Situation	Destination	Basis
Small and few, in the white and the yolk	Class B, industrial processing only	RIISPOA, art. 226, II and sole paragraph
Dark, or blood that also reaches the white	Unfit for human consumption	RIISPOA, art. 500, I

The line between the two cases depends on a visual judgement of size and reach. The table gives the rules the text states; the practical size criterion should be recorded in the establishment's procedure.

Can a camera detect blood spots inside the egg?

No. The Vigiovo camera analyses the shell, and the spot lies inside it. For that reason, Vigiovo does not detect blood spots in the interior of the egg. It classifies each egg as clean, dirty, cracked or unverified, with no class for internal defects.

These spots are seen on candling, the examination in which the egg is viewed against a strong light. Candling is mandatory in registered establishments and is part of grading (RIISPOA, art. 223, II and III). Without that step, an internal spot goes unnoticed and the egg can be graded wrongly.

For what Vigiovo does and what it leaves to other steps, see how it works.

Frequently asked questions

Can an egg with a blood spot be sold?: It depends on the size, the number and where the spot is. Small, few spots in the white and the yolk put the egg in Class B, intended for industrial processing (RIISPOA, art. 226). Dark spots or blood that also reach the white make the egg unfit for human consumption (art. 500, I).
What is the difference between blood on the shell and a blood spot inside the egg?: Blood on the shell is external dirt: it takes the egg out of Class A, which requires a clean shell (RIISPOA, art. 225, I). A spot inside the egg is an internal defect, and its class depends on its size and where it is. The two cases need different methods to be seen.
Can a camera find blood spots inside the egg?: Not inside. The Vigiovo camera analyses the shell and classifies the egg as clean, dirty, cracked or unverified. Spots inside the egg are seen only by candling, which is a mandatory step and comes before the final classification (RIISPOA, art. 223).

Sources

Decreto nº 9.013/2017 (RIISPOA), Presidência da República (Brasil)

How Vigiovo helps

Vigiovo grades eggs on the conveyor as clean, dirty, cracked or unverified, in real time, with deterministic computer vision: every decision comes with the measurements behind it, on an ordinary CPU.

See how it works