Explainer · Defects and grading
Can a thin-shelled egg be Class A in Brazil?
Yes, if the shell has no crack. MAPA's answer to question 31 says a thin-shelled egg can be Class A provided it meets article 225 of RIISPOA and has no crack. A thin shell alone does not take an egg out of Class A, but it needs attention on the line. A camera sees visible cracks and dirt, not shell thickness.
Updated · 3 min read
What is a thin-shelled egg?
It is an egg whose shell is thinner than normal for its batch. The shell, together with the shell membranes and the cuticle, is the barrier that protects the inside of the egg.
With less thickness, the shell has less margin to resist impact and pressure. That makes cracks more likely during collection, transport and grading.
Can a thin-shelled egg be Class A?
Yes, if the shell has no crack and the egg meets the other requirements. RIISPOA requires a Class A egg to have a shell and cuticle of normal shape, smooth, clean and intact (art. 225). MAPA's answer to question 31 applies that rule to thin shells: the thin shell by itself is not what takes an egg out of Class A.
| Situation | Class A? | Basis |
|---|---|---|
| Thin shell, no crack, clean | Can be, if it meets the other art. 225 requirements | MAPA FAQ, question 31 |
| Thin shell with a crack | No, the shell must be intact | RIISPOA, art. 225 |
| Thin shell, no crack, but dirty | No, the shell must be clean | RIISPOA, art. 225 |
Why does a thin shell need more attention on the line?
The main risk is cracking, because a crack decides whether the egg stays in Class A. In practice, three cases matter:
- Visible crack: a thin, elongated line that a camera can detect.
- Hairline crack: too fine to show under normal light, revealed only by candling or acoustic testing.
- Leaker: the crack has gone through the membranes and the contents are leaking.
What can a camera see on a thin-shelled egg?
A surface camera does not measure shell thickness. Vigiovo grades by what appears on the surface, such as visible cracks and dirt, and does not estimate thickness.
Hairline cracks need candling or acoustic testing, so a thin-shelled egg with no visible crack can still carry one. See the comparison in candling vs computer vision.
At the candling step, a thin-shelled egg is examined like any other, since RIISPOA requires candling examination in egg establishments (art. 223). On the conveyor, Vigiovo only flags a crack when it is elongated, long and runs into the shell. On video, each egg is measured three times and is rejected only if the crack shows up in two of them.
Frequently asked questions
Can a thin-shelled egg be Class A?
- Yes, if the shell has no crack and it meets the other requirements of article 225 of RIISPOA. MAPA gives this answer in question 31. A thin shell by itself does not downgrade the egg.
Can a camera detect thin shells?
- Not directly. A camera sees visible cracks and dirt on the surface, but it does not measure shell thickness. Hairline cracks still need candling or acoustic testing, including for this kind of egg.
What happens to a thin-shelled egg with a crack?
- It cannot be Class A, because the shell must be intact (RIISPOA, art. 225). If the shell is clean and the shell membrane intact, it goes to processing as soon as possible (art. 227). If it is dirty too, it is discarded (MAPA FAQ, question 5).
Sources
- Decreto nº 9.013/2017 (RIISPOA), Presidência da República (Brasil)
- Perguntas e respostas sobre a Portaria MAPA nº 612/2022 (versão de 05/06/2023), Ministério da Agricultura e Pecuária (MAPA)
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.