Lysozyme
What it does
Preservative (cheese).
How it's made
Extracted from egg white.
Lysozyme is a natural preservative — an enzyme that breaks down the cell walls of certain bacteria — used mainly to prevent unwanted bacterial growth in cheese, particularly to stop "late blowing" (gas and off-flavours) in hard cheeses. It is the same enzyme found in tears, saliva and egg white, where it forms part of natural defences.
Commercial lysozyme is extracted from hen egg white, which is an especially rich source. The egg white is processed to separate and concentrate the lysozyme, which is then purified — often by crystallisation — into a food-grade enzyme preparation.
The purified lysozyme is standardised for its activity and added in small amounts to cheese milk. Because it is derived from egg, its presence must be declared for people with egg allergy; it works by dissolving the walls of the specific bacteria that spoil cheese, protecting the product during maturation.
Possible reactions
Egg-derived — an allergen concern.