What an E number is
An E number is a code for a food additive authorised for use in the European Union — colours, preservatives, emulsifiers, thickeners, flavour enhancers and the like. The E stands for Europe. Additives are assessed for safety by the European Food Safety Authority and authorised under EU law. The same numbers are used, without the E, in the International Numbering System of the Codex Alimentarius, which is why codes such as 471 appear on labels far outside Europe.
An E number tells you that a substance is authorised and what it is chemically. It does not tell you where it came from, and nothing in the system records whether a product is halal.
Why the same number can be halal in one product and not in another
A code names a substance, not a recipe. Mono- and diglycerides of fatty acids are the same molecules whether they were made from palm oil or from pork fat, and the label may print E471 either way. Two products on the same shelf can carry the same code with different sources behind it.
Broadly, additives come from four kinds of source. Some are plant-based, mineral or synthetic in every commercial form: E100 curcumin from turmeric, pectin (E440) from citrus peel and apple, agar (E406) and carrageenan (E407) from seaweed, and the synthetic preservatives E202 potassium sorbate and E211 sodium benzoate. Some are made by fermentation: E330 citric acid from sugar with Aspergillus mould, and E621 monosodium glutamate from starch or molasses. Some come from animals: gelatine (E441) from skin and bone, E542 bone phosphate, E1105 lysozyme from egg white, and animal rennet, which has no E number, from the stomach lining of a calf. And a large group can be either plant or animal, depending on the manufacturer.
For an animal source, knowing the animal is not the whole answer. Beef gelatine and calf rennet are permissible only if the animal was slaughtered according to Islamic requirements, so "bovine" on a label does not settle it. Egg, the source of E1105, raises no slaughter question at all.
The additives people ask about most
Gelatine (E441) is made by boiling animal skin and bone — most commonly pork, sometimes beef — and is found in gums, marshmallows, some yoghurts and capsule shells. Fish gelatine also exists. Pectin and agar do the same gelling job from plants, and a product that uses them instead avoids the question.
E471, mono- and diglycerides of fatty acids, is the single most asked-about additive. It is an emulsifier in bread, cake, ice cream and margarine, made from fats that may be plant or animal, pork included, and the label almost never says which. E472e (DATEM), common in bread, is built on the same fatty acids and carries the same question. Look for a halal mark or a declaration of vegetable origin.
E120, cochineal or carmine, is a red colour made from crushed cochineal insects and used in yoghurts, sweets and drinks. The schools differ on eating insects other than locusts: the Maliki school is broadly permissive, the Hanafi and Shafi'i schools are not, and it is widely avoided for that reason. E904, shellac, is a resin secreted by the lac insect and used to glaze sweets, fruit and tablets. Because it is a secretion rather than the insect itself, several scholars treat it more leniently than carmine, but the schools differ here too.
E920, L-cysteine, is a dough conditioner in bread. It was historically produced from feathers, hog bristle or human hair; most is now made by bacterial fermentation, but not all, and it is common enough in bread to be worth checking.
Ethanol (E1510) is used as a solvent to carry flavourings rather than as a drink. The majority position is that a quantity too small to intoxicate, and not consumed as a drink, does not make the food prohibited; some hold to stricter avoidance.
Less famous, but the same question: glycerol (E422) and triacetin (E1518), which is built on it; stearic acid (E570), and magnesium stearate in tablets; and the flavour enhancers E631, E627 and E635 in crisps and instant noodles, which can come from meat, fish or fermentation. Beta-carotene (E160a) is itself plant or synthetic, but the carrier used to disperse it can be gelatine or animal fat. On the reassuring side, lecithin (E322) is almost always soya or sunflower.
What "doubtful" (mashbooh) means, and how to resolve it
Between what is clearly permitted and what is clearly prohibited lies the doubtful — mashbooh. With additives, the doubt is almost never about the ruling; it is about the facts. If the E471 in a loaf came from vegetable oil it is fine, if it came from pork fat it is not, and the packet does not say.
The customary practice is to leave the doubtful alone until the doubt is resolved, and resolving it usually means finding one fact. A halal mark from a certifying body answers it. A declaration of vegetable origin answers the source question for that ingredient. A vegan or vegetarian marking generally rules out ingredients from slaughtered animals, though it says nothing about alcohol used as a solvent. Failing those, ask the manufacturer in writing which source they use in that specific product. A written answer about one product is worth more than a brand's general reputation, because sources change when suppliers do.
Why certifying bodies do not always agree
Certifiers do not all apply the same standard. They differ on slaughter — whether stunning before slaughter is acceptable, and whether machine slaughter is. They differ on alcohol: how much residual ethanol a finished product may contain, and whether ethanol is acceptable as a processing aid at all.
They differ on transformation (istihala): whether a substance chemically transformed out of a prohibited source, such as gelatine or glycerol made from pork, takes a new ruling. Some jurists hold that complete transformation changes the ruling; others hold that it does not, or that industrial processing does not amount to complete transformation. And they differ, as the schools do, on insects, which decides E120 and E904.
What settles the question for the product in your hand
For a specific product, the answer is its own halal certification, or the manufacturer's statement about that product. This checker explains what each additive is made from and where the uncertainty lies. It cannot know which source a particular factory used last month. Where the source varies, treat the entry here as the question to ask and the certification as the answer.
If you do not recognise the certifying body, look it up: most publish their standards, and some national halal authorities list the bodies they recognise. Where the schools differ — on insects, on transformation, on traces of alcohol — the position of the school you follow is the one that answers your question.
To use the search above, type an E number (E471, or just 471), an additive's name, or a food such as bread. Each result shows its source category and links to its own page, with where it is found and what the question about it is.