King prawn flavour tails

What it is. A bright white pigment used to make sweets, icing, sauces and coatings look opaque and white.

Why it is used. Purely cosmetic. It changes appearance, not taste or safety of the food.

What the evidence says. In 2021 the EU food safety body EFSA concluded it could no longer be considered safe as a food additive, mainly because possible genetic damage from the tiny particles could not be ruled out. That is a precautionary call rather than proof of harm in people.

Banned as a food additive in the EU since 2022. Still permitted in the UK and the US, which reached different conclusions on the same evidence. A clear case of the same additive, different rules.

Assessed against EFSA, UK FSA, US FDA. Full entry for E171

What it is. A gel forming fibre extracted from red seaweed.

Why it is used. Thickens dairy, plant milks, desserts and some processed meats.

What the evidence says. Food grade carrageenan is permitted. A degraded form called poligeenan is harmful, but that is not what goes into food. Some lab and animal work links carrageenan to gut inflammation, which keeps it under review, but human evidence is limited and mixed.

Permitted, including in organic food in many places, though a few specialist products avoid it as a precaution.

Assessed against EFSA, JECFA. Full entry for E407

What it is. A sugar alcohol, about half as sweet as sugar, which also holds moisture.

Why it is used. Used in sugar free sweets and gum, and to keep baked goods soft.

What the evidence says. Not a toxicity question at all. Sugar alcohols are poorly absorbed, so a large amount draws water into the gut and has a laxative effect. That is well established, predictable and dose dependent, which is why the label has to say so.

Permitted. Foods with more than 10 per cent polyols must carry the statement that excessive consumption may produce laxative effects.

Assessed against EFSA, UK FSA. Full entry for E420

What it is. The sodium salt of glutamate, an amino acid found naturally in tomatoes, cheese and mushrooms.

Why it is used. Boosts savoury, umami flavour in stocks, crisps, ready meals and sauces.

What the evidence says. The old idea of MSG causing headaches and flushing, once called Chinese restaurant syndrome, has not held up in controlled trials. Regulators worldwide treat it as safe at normal intake. A genuinely useful example of a feared additive that the evidence exonerates.

Permitted and classed as safe. Adds to total sodium, so it counts towards salt if a product uses a lot.

Assessed against EFSA, JECFA, US FDA. Full entry for E621