Explainer · Defects and grading
Faecal contamination on eggs: what to do with them in grading
An egg with faecal dirt on an intact shell is unfit for human consumption as it is (RIISPOA, art. 500 V). In Brazil, if the shell is intact and the egg goes to industrial processing, mechanical washing is mandatory. If the shell is also cracked, the egg has no use as human food and must be discarded.
Updated · 5 min read
What counts as faecal dirt on an egg?
Faecal dirt is excrement stuck to the shell of an egg that is still whole. RIISPOA treats this case specifically: eggs with "external dirt from faecal material" are unfit for human consumption in the form they are in (art. 500 V). The same item also covers eggs that have come into contact with substances able to transmit strange odours or flavours.
An egg with faeces on its shell is also a dirty egg. It falls outside Class A, which requires a shell of normal shape, smooth, clean and intact (art. 225, I). So faecal dirt is not only a matter of appearance: it changes where the egg can go.
What is the risk of an egg with faecal dirt?
The risk is microbiological. Faecal material can carry microorganisms onto the surface of the shell, and the rules treat the penetration of those microorganisms as the problem washing must solve. MAPA requires washing to be done entirely by mechanical means, with procedures that prevent microbial penetration into the interior of the egg (MAPA, question 30).
The decision about an egg depends on two questions: is the shell whole or cracked, and is the egg going to industrial processing? The next section covers each case.
Can an egg with faecal dirt be washed?
Yes, if the shell is whole and the egg is going to industrial processing. MAPA says washing is mandatory only for eggs that are both dirty and intact, and for eggs that will go to industrial processing (question 28). MAPA Ordinance 612/2022 defines washing as the step that sanitises eggs and makes it mandatory for dirty, uncracked eggs going to industrial processing (art. 18, as stated in question 38).
A dirty egg with faecal dirt that is also cracked is a different case. RIISPOA bans using or washing dirty cracked eggs to make egg products (art. 228). MAPA states that they have no use at all as human food and must be discarded immediately, or broken into an identified container to guarantee their correct destination (questions 5 and 26).
| Situation | Destination under the rules |
|---|---|
| Faecal dirt, shell whole | Unfit as it is (art. 500 V); mechanical washing for industrial processing (question 28) |
| Faecal dirt and cracked | No use as human food (question 5); cannot be washed for egg products (art. 228) |
| Clean, shell whole | Can be Class A if it meets the other requirements of art. 225 |
What can a camera see in this case?
A camera sees the dirt on the surface, but cannot tell what material it is made of. Faeces, soil, blood and yolk stuck to a shell can look alike in colour and brightness, and grading does not separate cases by the origin of the dirt.
Vigiovo measures the area of dirt on the shell and grades the egg as dirty when that area reaches 3% or more of the visible shell. That is a configuration value, calibrated on each line, not a legal standard. It separates dirty eggs from clean ones; it does not say whether the dirt is faecal, and it does not see inside the egg. Details in how it works.
To find where the dirt comes from, the quality team has to look at the house and the collection system. See also dirty eggs: what counts as dirty and how to identify cracked eggs.
How do you reduce faecal dirt on the farm?
The dirt starts in the house, not at grading. As a general rule of practice, the longer an egg stays in the nest or cage, the greater the chance that dirt sticks to the shell. The factors that matter most are:
- frequent collection, so eggs spend less time in the nest;
- clean, dry nests and litter;
- maintained collection belts, so broken eggs do not smear their neighbours;
- tracking the dirty-egg rate per house and per day, to notice changes early.
The washing rules, including what changes for each destination, are in egg washing rules in Brazil. On what a camera cannot see inside the egg, see candling vs computer vision.
Frequently asked questions
Can an egg with faeces on its shell be sold?
- Not in the form it is in. RIISPOA treats an egg with external dirt from faecal material as unfit for human consumption (art. 500 V). If the shell is whole, the egg can go to industrial processing after mechanical washing (MAPA, question 28).
Can a dirty, cracked egg with faecal dirt be used?
- Not for human food. MAPA states that dirty cracked eggs have no use as human food (question 5). RIISPOA also bans using or washing dirty cracked eggs to make egg products (art. 228).
Can Vigiovo tell faecal dirt from other dirt?
- No. Vigiovo measures the area of dirt on the shell and grades the egg as dirty when that area passes its configured limit. It does not identify what the dirt is made of, and it does not see inside the egg. The source of the dirt has to be traced on the farm.
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.