# How to identify cracked eggs during grading > A cracked egg, or check, has a broken shell but intact shell membranes; if the membranes also break and the contents leak, it is a leaker. Visible cracks are found by visual inspection or a camera; hairline cracks need candling or acoustic testing. In Brazil, clean cracked eggs go to industrial processing, and eggs that are both dirty and cracked are discarded. Updated: 2026-10-09 · URL: https://vigiovo.com/en/resources/how-to-identify-cracked-eggs · Português: https://vigiovo.com/recursos/como-identificar-ovos-trincados.md ## Key takeaways - A check (broken shell, intact membranes) and a leaker (membranes broken) are different defects with different destinations. - Class A requires an undamaged shell, so no cracked egg can be sold as Class A in Brazil or the EU. - In Brazil a clean cracked egg with intact membranes goes to processing; a dirty cracked egg has no use as human food. - Cameras detect visible cracks; hairline cracks need candling or acoustic testing. ## What is a cracked egg? A cracked egg is one whose shell is cracked or broken while its [shell membranes](https://vigiovo.com/en/resources/glossary#shell-membranes) remain whole, with nothing leaking. US regulations use exactly that test: a check is an egg with a broken or cracked shell whose membranes are intact and contents not leaking (7 CFR 57.1). When the crack also breaks the membranes and the contents are exposed or exuding, the egg is no longer a check but a [leaker](https://vigiovo.com/en/resources/glossary#leaker). The difference matters because the membranes are the last barrier between the inside of the egg and the environment. ## Why can't a cracked egg be sold as Class A? Brazil's RIISPOA requires [Class A](https://vigiovo.com/en/resources/glossary#class-a) eggs to have a shell and cuticle "of normal shape, smooth, clean, intact" (Decree 9.013/2017, art. 225). The EU rule is equivalent: shell and cuticle of normal shape, clean and undamaged (Delegated Regulation (EU) 2023/2465, art. 3). So a crack takes the egg off the table even when the inside looks perfect. Where it goes next depends on two things: whether the membranes are intact and whether the shell is clean. **Where a cracked egg goes in Brazil** | Situation | Destination | Basis | | --- | --- | --- | | Clean, cracked, membranes intact | Industrial processing, as quickly as possible | RIISPOA, art. 227 | | Dirty and cracked | Banned from egg products; discarded immediately | RIISPOA, art. 228; MAPA FAQ on Ordinance 612 | | Shell and membranes broken, contents exposed | Unfit for human consumption | RIISPOA, art. 500 | ## What types of crack are there? In grading practice, cracks are sorted by how visible they are: - **Visible crack**: a thin, elongated line you can see by eye or in a photo, often branching. - **Star crack**: several short lines radiating from an impact point. - **[Hairline crack](https://vigiovo.com/en/resources/glossary#hairline-crack)**: too fine to show under normal light; only candling or acoustic testing reveals it. - **Leaker**: the crack has gone through the membranes and contents are leaking. ## How do you identify cracked eggs, and which method detects what? No single method catches every crack. Each sees part of the problem, and grading lines combine more than one: **Crack detection methods** | Method | Detects | Misses | Speed | | --- | --- | --- | --- | | Human visual inspection | Visible cracks and leakers | Hairline cracks; fatigue at volume | Limited by the operator | | Camera with computer vision | Visible cracks, leakers, dirt | Hairline cracks | Continuous, egg by egg | | Candling (light behind the egg) | Fine and hairline cracks, interior defects | Light dirt on the shell | Depends on operator or machine | | Acoustic testing | Hairline cracks, through the change in resonance | Dirt and interior defects | High, on dedicated equipment | Candling is mandatory in registered Brazilian establishments (RIISPOA, art. 223). A camera placed before it doesn't replace it: it removes dirty and visibly cracked eggs so candling works on a cleaner batch. See the full comparison in [candling vs computer vision](https://vigiovo.com/en/resources/candling-vs-computer-vision). ## How does Vigiovo detect cracks on the conveyor? Vigiovo looks for cracks with [black-hat and top-hat](https://vigiovo.com/en/resources/glossary#black-hat-top-hat) filters, which highlight thin lines darker or lighter than the shell. A line only counts as a crack if it is elongated (at least 5 times longer than wide), long (at least 0.35 of the egg radius) and deep (it reaches at least 0.4 of the radius into the shell instead of following the rim). If the total crack length reaches 0.8 of the radius, the egg is graded cracked. That limit is a Vigiovo configuration value, tuned when each line is calibrated, not a legal standard. On video each egg is measured 3 times as it passes and rejected only if the crack shows up in 2 of them. Details in [how it works](https://vigiovo.com/en/how-it-works). ## Frequently asked questions ### Can a cracked egg be eaten? A cracked egg cannot be sold as Class A. In Brazil, if the shell is clean and the membranes are intact, it goes to industrial processing as quickly as possible (RIISPOA, art. 227). If it is dirty and cracked, it has no use as human food and must be discarded. ### What is the difference between a check and a leaker? In a check the shell is cracked but the shell membranes are intact and nothing leaks. In a leaker the shell and membranes are broken and the contents are exposed or exuding (7 CFR 57.1). ### Can a camera detect hairline cracks? No. Hairline cracks don't show under normal light, so no ordinary camera sees them. They need candling or acoustic testing. A camera catches visible cracks and dirt before those steps. ## Sources - [Decreto nº 9.013/2017 (RIISPOA)](https://www.planalto.gov.br/ccivil_03/_ato2015-2018/2017/decreto/d9013.htm), Presidência da República (Brasil) - [7 CFR § 57.1 Definitions (Inspection of Eggs)](https://www.ecfr.gov/current/title-7/subtitle-B/chapter-I/subchapter-C/part-57/subpart-A/section-57.1), U.S. Electronic Code of Federal Regulations - [Delegated Regulation (EU) 2023/2465, marketing standards for eggs](https://eur-lex.europa.eu/eli/reg_del/2023/2465/oj/eng), EUR-Lex - [Perguntas e respostas sobre a Portaria MAPA nº 612/2022 (versão de 05/06/2023)](https://wikisda.agricultura.gov.br/manual_ovos/perguntas_e_respostas_port612_2023.pdf), Ministério da Agricultura e Pecuária (MAPA) ## Read next - [Dirty eggs: what counts as dirty and how to grade them](https://vigiovo.com/en/resources/dirty-egg-grading.md) (Guide, 2026-10-09): When an egg counts as dirty, whether it can be washed, where it goes under Brazilian and EU rules, and how to measure shell dirt with a camera. - [Candling vs computer vision: what each one detects](https://vigiovo.com/en/resources/candling-vs-computer-vision.md) (Comparison, 2026-10-09): Candling compared with camera inspection in egg grading: which defects each detects, speed, record keeping and why the two methods work best together. ## 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.