E-numbers / Preservatives / E1105
also: egg-white lysozyme · hen egg lysozyme · muramidase
A natural enzyme from hen egg white, used mainly in hard cheese to stop unwanted bacterial fermentation during ripening.
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Medium Fat Hard Cheese [Medium Fat Hard Cheese (Unpasteurised Milk), Preservative (Egg Lysozyme)], Anti-Caking Agent (Cellulose)
Derived from egg white, a declarable allergen.
73
of the 43,325 UK supermarket foods we checked declare E1105 in their ingredients
That is 0.2%, counted by its code or its name.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Why it’s worth knowing. Derived from egg white, a declarable allergen. People with egg allergy must check labels: any food containing E1105 must declare it contains egg.
Lysozyme is a naturally occurring enzyme protein found in high concentrations in hen egg white. It is extracted and purified from eggs for use as a food preservative. The same enzyme is also present in human tears, saliva, and breast milk, where it plays a role in natural antimicrobial defence.
Lysozyme kills bacteria by attacking a key structural component of their cell walls, causing the cells to burst. In food, it targets Gram-positive bacteria, most importantly Clostridium tyrobutyricum, which causes a spoilage defect in hard and semi-hard cheeses called 'late blowing' (unwanted gas pockets and off-flavours forming during ripening). At the concentrations used in food it does not affect most Gram-negative bacteria.
Found primarily in hard and semi-hard cheeses such as Grana Padano, Gouda, Emmental, and aged Cheddar, where it is added to the milk before curdling. Also permitted in some wines to control lactic acid bacteria. On a label it appears as 'lysozyme', 'E1105', or 'egg white lysozyme', always accompanied by an egg allergen declaration.
Because lysozyme is a protein extracted from hen eggs, it is classified as an egg-derived ingredient and carries the same legal allergen status as egg white itself. Residual lysozyme protein can remain in finished cheeses at levels capable of triggering allergic reactions in egg-sensitive people. UK and EU food law require any food containing lysozyme to declare 'egg' in the allergen list, typically in bold on the label.
Residual lysozyme in Grana Padano-type cheeses was found at concentrations sufficient to trigger IgE-mediated reactions in egg-allergic individuals.
UK assimilated Regulation (EU) 1169/2011 (Food Information to Consumers) requires egg to be declared as an allergen in any food in which lysozyme (E1105) is used, regardless of the final residual level.
Lysozyme is highly effective against Gram-positive bacteria, which is why it works well against Clostridium species in cheese. However, it has little to no effect on most Gram-negative bacteria, which dominate many food spoilage and food safety concerns. Its activity also diminishes in acidic or very salty environments. It is not a broad-spectrum preservative.
Lysozyme effectively inhibits Clostridium tyrobutyricum in cheese at permitted use levels, preventing late blowing without significantly altering cheese flavour or texture.
Lysozyme has been evaluated by EFSA and the Scientific Committee on Food. No genotoxic, carcinogenic, reproductive, or developmental effects have been identified. As an enzyme present naturally in human biology, its toxicological profile is well understood. No numerical ADI has been set because the enzyme is broken down to amino acids in the gut like any dietary protein.
EFSA's Panel on Food Additives and Nutrient Sources (ANS) concluded that lysozyme does not raise concerns for genotoxicity or carcinogenicity, and that no numerical ADI is necessary given its nature as a protein enzyme.
Anyone with an egg allergy must avoid foods containing E1105, as it is derived from hen egg white and can trigger allergic reactions. Look for 'lysozyme', 'E1105', or 'egg' in the allergen declaration, typically printed in bold in the ingredients list. Hard aged cheeses are the most common source.
The one real issue here is straightforward: lysozyme comes from eggs, so egg-allergic shoppers need to check the label. UK law requires the allergen to be declared, so the information should always be visible. Beyond the allergen question, lysozyme is an enzyme the human body itself produces; it breaks down entirely during digestion. The science on broader health effects is quiet because there is nothing unusual to investigate. The concern is narrow, specific, and manageable with label-reading.
No. E1105 Lysozyme is approved for use in the UK as a food additive. It appears on the UK FSA approved additives list with authorised status confirmed as of 31 December 2020.
Yes, if you have an egg allergy. Lysozyme is extracted from hen egg white and is classed as an egg-derived allergen. UK law requires any food containing it to declare egg on the label, usually in bold. People with egg allergy have reported reactions to cheeses preserved with lysozyme.
Mainly hard and semi-hard cheeses such as Grana Padano, some Gouda, Emmental, and aged Cheddar. It is added to the milk before the cheese is made. It can also appear in some wines. Check the ingredients list for 'lysozyme', 'E1105', or 'egg' in the allergen statement.
No. Lysozyme is extracted from hen egg white, making it unsuitable for vegans and vegetarians who avoid eggs. Cheeses containing E1105 also carry an egg allergen declaration.
Last reviewed: 20 June 2026
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