Are Nisin and Natamycin (E234, E235) Halal?

Nisin (E234) and natamycin (E235) are preservatives made by microbes. Nisin is a small protein produced by Lactococcus lactis, the same kind of bacterium that sours milk. Natamycin is an anti-mould compound produced by the soil bacterium Streptomyces natalensis. Both are made by fermentation, neither involves an animal, and both are Halal.^[3][5]

What they do

• Nisin stops certain bacteria, especially spore-formers. It is used in processed and spreadable cheese, some cream desserts, tinned foods and, in some countries, cooked meats. US rules list it as a generally recognised food substance.^[2]
• Natamycin stops moulds and yeasts on surfaces. Its main EU use is on the rind of hard and semi-hard cheeses and on the casing of dry sausages, where it keeps mould off without getting into the food much.

EFSA has reviewed nisin for use across these foods.^[1] Certifier E-number lists put both with the additives that need no source check.^[6]

"Grown on milk"

Nisin is often produced in a dairy-based fermentation broth, which is why it sometimes appears in discussions about vegan foods. For Halal purposes this changes nothing: milk is Halal, and the preservative is purified from the broth.

The food still decides

These preservatives are almost always found on foods that have their own question:

• Cheese with natamycin on the rind still depends on how it was set. Microbial rennet or rennet from a Halal-slaughtered animal is Halal, pork rennet is not, and rennet from a calf not slaughtered Islamically is a scholarly difference; see cheese.
• Dry sausages with natamycin on the casing depend on the meat and its slaughter; see salami.
• Processed cheese with nisin depends on the cheeses and emulsifying salts in it.

For the everyday preservative in cakes, drinks and dips, see potassium sorbate (E202).