# What is the egg cuticle, and why does washing matter? > The cuticle is the thin film that covers the shell and helps seal its pores. RIISPOA includes it among the Class A requirements, and the European Union bans washing Class A eggs because washing can remove it. A surface camera cannot measure the cuticle directly. Updated: 2026-10-09 · URL: https://vigiovo.com/en/resources/eggshell-cuticle · Português: https://vigiovo.com/recursos/cuticula-do-ovo.md ## Key takeaways - The cuticle covers the shell, and Class A requires both to be of normal shape, smooth, clean and intact (RIISPOA, art. 225, I). - The European Union bans washing or cleaning Class A eggs, before or after grading (Delegated Regulation (EU) 2023/2465, art. 4). - The Brazilian washing rule comes from a different instrument, and the details are in [egg washing rules in Brazil](https://vigiovo.com/en/resources/egg-washing-rules-brazil). - A surface camera does not see the cuticle directly; it assesses the shell. ## What is the egg cuticle? The [cuticle](https://vigiovo.com/en/resources/glossary#cuticle) is a thin film that covers the shell on the outside. It helps seal the pores of the shell, the small openings through which gas and moisture pass. Because it sits on the surface, the cuticle is the layer most exposed to handling, dirt and washing. It does not show up as a separate line on the shell, and its loss is hard to notice with the naked eye. ## Why does the cuticle appear in the Class A requirements? RIISPOA describes the shell and the cuticle together: Class A requires "shell and cuticle of normal shape, smooth, clean, intact" (Decree 9.013/2017, art. 225, I). In practice, the cuticle falls under the same test as the shell and is not a separate requirement. The Brazilian text focuses on the result, a clean and intact cuticle. It does not describe how to preserve it, which is left to each establishment's process. For what counts as [Class A](https://vigiovo.com/en/resources/glossary#class-a), see [Brazil's Class A requirements](https://vigiovo.com/en/resources/brazil-category-a-eggs). ## Why can washing affect the cuticle? Washing removes dirt, but it can also remove the cuticle. This is one reason the European Union bans washing or cleaning Class A eggs, before or after grading (Delegated Regulation (EU) 2023/2465, art. 4). The regulation provides for exceptions, which are not detailed here. In practice, a Class A egg has to arrive at grading clean, because it cannot be cleaned afterwards. An egg that stops meeting these characteristics is downgraded to Class B (art. 3(2)). ## How do the shell and washing rules compare? The two texts set similar requirements for the shell, but they regulate washing differently. The table summarises what the articles cited say, read directly from the texts. **Shell, cuticle and washing in the cited texts (a reading of the articles, not a full list)** | Topic | Brazil (RIISPOA) | European Union (Regulation 2023/2465) | | --- | --- | --- | | Shell and cuticle for Class A | Of normal shape, smooth, clean and intact (art. 225, I) | Of normal shape, clean and undamaged (art. 3(1)(a)) | | Washing Class A eggs | No general ban in the cited articles; washing dirty cracked eggs for egg products is banned (art. 228) | Banned, before or after grading (art. 4(1)) | | Egg that loses Class A characteristics | No longer meets art. 225 | Downgraded to Class B (art. 3(2)) | The European text is more direct about washing, and the Brazilian one is more detailed about where each type of egg goes. For where dirty and cracked eggs go, see [how to identify cracked eggs](https://vigiovo.com/en/resources/how-to-identify-cracked-eggs). ## Can a camera check the cuticle? Not directly. A camera sees the surface of the shell, with its colour, brightness, dirt and visible cracks, but it does not measure the cuticle as a separate layer. Vigiovo grades dirt and cracks on the shell and does not assess the cuticle, so a clean camera result does not guarantee that the cuticle is intact. Details in [how it works](https://vigiovo.com/en/how-it-works). What a camera helps separate is what sits on top of the shell: [adhering dirt](https://vigiovo.com/en/resources/glossary#dirty-egg), natural colour variation and visible cracks. See how each case is handled in [dirty eggs: what counts as dirty](https://vigiovo.com/en/resources/dirty-egg-grading). ## Frequently asked questions ### Is the egg cuticle the same thing as the shell? No. The shell is the hard part of the egg, and the cuticle is the thin film that covers it on the outside and helps seal its pores. RIISPOA requires both to be of normal shape, smooth, clean and intact for Class A (art. 225, I). ### Why does the European Union ban washing Class A eggs? Delegated Regulation (EU) 2023/2465 says Class A eggs shall not be washed or cleaned, before or after grading, except as provided for (art. 4). One reason is that washing can remove the cuticle, which helps seal the pores of the shell. ### Can a camera measure the cuticle? Not directly. A surface camera sees the shell, with its colour, brightness, dirt and visible cracks, but it does not measure the cuticle as a separate layer. Vigiovo grades dirt and cracks on the shell and does not assess the cuticle, so keeping it intact depends on handling and washing. ## Sources - [Delegated Regulation (EU) 2023/2465, marketing standards for eggs](https://eur-lex.europa.eu/eli/reg_del/2023/2465/oj/eng), EUR-Lex - [Decreto nº 9.013/2017 (RIISPOA)](https://www.planalto.gov.br/ccivil_03/_ato2015-2018/2017/decreto/d9013.htm), Presidência da República (Brasil) ## Read next - [Star cracks: recognising impact damage on the shell](https://vigiovo.com/en/resources/star-cracks.md) (Explainer, 2026-10-09): How to recognise a star crack, when it counts as a check rather than a leaker, and why short branching lines are hard to measure from an image. - [Hairline cracks in eggs: why cameras miss them](https://vigiovo.com/en/resources/hairline-cracks-in-eggs.md) (Explainer, 2026-10-09): What a hairline crack in an egg is, why it does not show under normal light, how candling and acoustic testing reveal it and what Vigiovo detects. - [How to identify cracked eggs: types, methods and rules](https://vigiovo.com/en/resources/how-to-identify-cracked-eggs.md) (Guide, 2026-10-09): What a cracked egg (check) is, how it differs from a leaker, which methods detect each kind of crack and where cracked eggs must go under the regulations. ## 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. https://vigiovo.com/en/how-it-works.md 4 min read.