The Same Dye Can Be in Your Cereal and Your Detergent

Here's a fact that surprises almost everyone. A single dye molecule can appear in your breakfast cereal and in a household cleaning product, listed under two completely different names on the two labels. Nothing shady is happening. It's just that food and non-food products use different naming systems for the same colorants, which makes the overlap almost invisible unless you know how to spot it.

Once you know the trick, ingredient labels become considerably more interesting. Let's decode it.

One Molecule, Several Names

Synthetic colorants get named according to the system in use, and there are several systems running at once.

Take Brilliant Blue FCF. In American food it's labelled FD&C Blue No. 1. In Europe it's E133. In the international Colour Index used across dyes and pigments it's CI 42090. And in non-food contexts, the same molecule is commonly known as Acid Blue 9.

Four names, one substance. A shopper comparing a cereal box to a cleaning product label would have no obvious way of knowing they were looking at the same thing, because the labels aren't speaking the same language.

The Color Index Is the Decoder Ring

If you want to cut through the naming confusion, the Color Index number is the thing to look for.

CI numbers identify the actual chemical, regardless of what industry is using it or what marketing name it goes by. Tartrazine is FD&C Yellow 5 in food, E102 in Europe, and CI 19140 everywhere. Sunset Yellow FCF is Yellow 6, E110, and CI 15985. Allura Red AC is Red 40, E129, and CI 16035.

Cleaning products don't typically print CI numbers on the front of the pack, and food labels don't either. But once you know the same molecules travel between categories under different names, the phrase "contains colour" on any label stops feeling like a throwaway detail.

Why Colorants Turn Up Across So Many Categories

This isn't a conspiracy, it's economics and chemistry.

Synthetic colorants are stable, consistent, inexpensive and produced at industrial scale. A dye that reliably delivers the same blue batch after batch is useful to anyone selling something that needs to look a particular way, whether that's a cereal, a drink, a shampoo or a cleaning product. So the same well-characterised molecules end up used broadly.

What they have in common everywhere is the job description. Colorants make a product look a certain way. In cereal, the colour isn't nutrition. In detergent, the color isn't cleaning. In both cases it's there for your eyes.

The Detergent Version of the Story

Cleaning products use colorants for two purposes, and it's worth separating them.

First, colouring the product itself, so the liquid or powder looks the way shoppers expect. 

Neither purpose involves removing soil. Cleaning comes from surfactants lifting oil and dirt, enzymes breaking down specific stains, and oxygen working on the bonds that make stains visible.

How to Spot Colorants on Any Label

The good news is that this check takes seconds once you know the vocabulary.

On food, look for colour names with numbers: Blue 1, Yellow 5, Red 40, or E-numbers in the 100s. On household products, look for terms like colorant, dye, CI followed by a five-digit number, or names in the Acid Blue and Basic Violet families. Words like hueing agent or bluing agent point specifically at dye meant to tint fabric.

And the simplest signal of all: if a product isn't coloured, there's nothing to look for. CocoClean's laundry powder contains no synthetic dyes at all, so no colorant appears on the list under any naming system.

Frequently Asked Questions

Can the same dye be in food and cleaning products?

Yes. Colorant molecules are identified differently across industries. Brilliant Blue FCF, for example, is FD&C Blue No. 1 in American food, E133 in Europe, CI 42090 in the Colour Index, and Acid Blue 9 in non-food contexts.

What is a CI number?

A Color Index number, an international identifier for a specific colorant molecule. It stays the same regardless of industry or trade name, which makes it the most reliable way to identify what a dye actually is.

Why do cleaning products contain dye at all?

To color the product so it looks the way shoppers expect.

How do I avoid dyes in laundry detergent?

Check the ingredient list for colorant, dye, CI numbers, or hueing and bluing agents. A product with no synthetic dyes will have none of these listed. CocoClean's powder contains no synthetic dyes.

The Bottom Line

The same colorant molecule can genuinely appear in a breakfast cereal and a cleaning product, hidden behind different naming systems in each. The Colour Index number is what links them, and the job the dye does is the same in both places: make something look a particular way.

CocoClean's laundry powder skips the whole question by containing no synthetic dyes, alongside no added fragrance and no optical brighteners.

Nothing added for looks. Cleans like a dream.