Lysozyme (E1105) — Hidden Processing Agent — Is It Vegan?

Lysozyme appears most often in hard and semi-hard cheeses. During ripening, Clostridium tyrobutyricum can germinate from heat-resistant spores and ferment lactic acid to produce gas, causing a defect known as late blowing — cracks, splits, and off-flavors. Adding lysozyme to the cheese milk inhibits these bacteria, serving as an alternative or supplement to nitrate salts. It is commonly associated with Gouda, Edam, Grana Padano, Manchego, and some Parmesan-style cheeses, though use varies by producer.

In winemaking, lysozyme is used to control lactic acid bacteria, allowing producers to manage or delay malolactic fermentation and to reduce reliance on sulphur dioxide. It also has pharmaceutical and over-the-counter uses, such as in some throat lozenges. In each case the enzyme works at the production stage rather than appearing as a headline ingredient, which is why checking the label is necessary.

Because commercial lysozyme is extracted from hen eggs, any product containing E1105 is not vegan, and it is also relevant to people with egg allergies. In cheesemaking, producers who avoid lysozyme have several established options for controlling late blowing: nitrate salts, bactofugation (spinning spores out of the milk by centrifuge), microfiltration, and stricter milk hygiene. These methods target the same spoilage bacteria without an egg-derived additive, though they do not make a dairy cheese vegan.

For those seeking fully plant-based options, the practical alternative is choosing dairy-free cheeses and wines made without animal-derived processing aids. In wine, sulphur dioxide remains the conventional microbial control, and many producers now market low-intervention or vegan-certified bottles. Looking for vegan certification or an allergen statement is the most reliable way to confirm a product was made without lysozyme.

In the European Union, lysozyme derived from egg is treated as a declarable allergen. Foods and beverages that contain it must indicate the presence of egg, appearing on labels as wording such as 'lysozyme (egg),' 'E1105,' or 'enzyme (egg).' For wine, allergen labeling of egg-derived lysozyme has been required in the EU since the 2012 vintage, which makes affected wines easier to identify than those fined with isinglass, which may not always trigger an allergen declaration.

In the United States, egg is one of the major allergens covered by federal food labeling law, so an egg-derived ingredient like lysozyme must be disclosed on packaged foods that contain it. These rules mean that, while lysozyme is a production-stage aid, its egg origin usually surfaces somewhere in the allergen information. Reading the full ingredient and allergen statement, rather than only the main ingredient list, is the surest way to catch it.