Raw Milk, Thermised and Pasteurised Cheese

A strong, atypical flavour, followed by a downgrade. The raw milk Cheddar was the disappointment in an experiment by McSweeney and colleagues.[9] If you expect a treatment label to promise deliciousness, here is your first surprise: it tells you how the milk was handled, not whether you will want a second slice.

The difference between raw milk, thermised and pasteurised cheese starts before cheesemaking. Heat changes the milk's microbial population and some enzymes, shaping risk control and ripening. Recipe, hygiene and storage matter too, and pasteurisation cannot prevent contamination after treatment.[1][3][8][9][16]

Your quick guide to the milk behind the cheese

• In the EU and Great Britain, raw milk has not been heated above 40 °C or undergone a treatment with an equivalent effect.[1][2]
• Codex describes thermisation as less intense than pasteurisation but gives no temperature band.[3]
• Many US cheese standards require at least 60 days of curing at no less than about 1.7 °C (35 °F) when unpasteurised dairy ingredients are used.[5]

Pull up a chair at the cheese vat

Each treatment changes what enters the vat. The table helps you separate what happens to the milk from what that means for safety and flavour. The processing definitions apply to the jurisdictions named; the flavour findings come from particular experimental cheeses.[8][9]

Treatment and where it applies	What happens to the milk	What it means for microbes	What flavour research found
Raw milk, EU and GB	Milk from farmed animals has not been heated above 40 °C or undergone a treatment with an equivalent effect.[1][2]	There is no pasteurisation step to kill susceptible pathogens in the milk.[3]	Naturally occurring flora and enzyme activity remain and can influence ripening.[8][9]
Thermised milk, Codex reference	Heat treatment is less intense than pasteurisation and aims to reduce microorganisms.[3]	It reduces microorganisms rather than providing pasteurisation's validated pathogen control.[3]	Experimental thermisation changed both flora and a milk enzyme involved in fat breakdown.[8]
Pasteurised milk, EU and GB	At least 72 °C for 15 seconds, at least 63 °C for 30 minutes, or an equivalent treatment.[1][2]	Treatment controls susceptible pathogens, but contamination can happen afterwards.[3][16]	Microbes and enzymes remain active during ripening; starter enzymes contributed in experimental Cheddar.[8]

Why heated curd can still mean raw milk cheese

You might see curd being heated and wonder how the cheese can still be called raw. EU Regulation 853/2004 makes the distinction: raw describes the milk, not the highest temperature the curd reaches later. Curd is the coagulated part of milk that becomes cheese, and heating it is a different operation from pasteurising the incoming milk. Australia's cheese processing rules make this distinction explicit too.[1][10]

EU pasteurisation rules include a negative alkaline phosphatase test immediately after treatment, where applicable. This measures the activity of an enzyme used as a treatment indicator. Where the test is unsuitable, for example for some non-bovine products, the EU text allows other assurances under the operator's hazard control system.[1]

Great Britain's assimilated version of Regulation 853/2004 keeps the raw milk definition and the principal pasteurisation options. Later EU provisions do not automatically change Great Britain's law.[2]

In the United States, 21 CFR 133.3(d) defines pasteurisation for dairy ingredients in cheese. Familiar options are approximately 63 °C (145 °F) for 30 minutes or 72 °C (161 °F) for 15 seconds, applied to every particle. The regulation also lists shorter, hotter treatments. For an ingredient containing at least 10% fat, the specified temperature must rise by about 2.8 °C (5 °F).[5]

Thermisation: a gentler heat, a distinct treatment

Thermisation turns down the heat, but it has its own definition. Codex describes it as less intense than pasteurisation, with the purpose of reducing microorganisms. Its milk hygiene code gives no temperature band, and Codex is an international reference with legal force where incorporated into applicable law.[3]

For a specific historical definition, look to the UK's 1995 Dairy Products (Hygiene) Regulations. These specified 57 °C to 68 °C for at least 15 seconds, with a positive phosphatase reaction. Those figures belong to that historical law, not a current worldwide standard.[4] In a controlled Cheddar experiment, researchers used 65 °C for 15 seconds for thermisation and 72 °C for 15 seconds for pasteurisation.[8]

Flavour has a whole cast of characters

Heat changes the participants in ripening; it does not switch ripening off. Raw milk brings its own enzymes and naturally occurring microorganisms, known as indigenous flora. In Hickey and colleagues' Cheddar experiment, researchers compared three milk treatments over 168 days of ripening.[8]

Heat reduced both the number and diversity of microorganisms. It also extensively or completely inactivated lipoprotein lipase, a milk enzyme that releases fatty acids from fat.[8]

Yet the milk's own enzymes were not doing most of that work. Enzymes from the starter culture, the microorganisms added to guide fermentation, were the main contributors to fat breakdown in all three cheeses. The milk's own enzyme activity contributed more in the raw milk cheese and less in its thermised counterpart.[8]

More microbial activity can give you a different flavour without giving you a better one. McSweeney and colleagues compared raw, pasteurised and microfiltered Cheddar: commercial graders and a trained taste panel rated the pasteurised and microfiltered cheeses highly, unlike the downgraded raw milk cheese. These results belong to the cheeses and conditions studied, but the reminder is useful: judge the cheese, not its treatment label. Your cheeseboard need not become an ideological commitment.[9]

What the sixty-day rule can and cannot tell you

Many US cheese standards permit unpasteurised dairy ingredients only when the cheese is cured for at least 60 days at no less than about 1.7 °C (35 °F). Notice that the temperature is a minimum, not a maximum. The particular cheese standard determines which route is permitted.[5]

That ageing period does not guarantee freedom from pathogens. During its fiscal year 2014 to 2016 assignment, FDA tested 1,606 raw milk cheeses aged for 60 days and detected Listeria monocytogenes in 10 samples, or 0.62%. Those are results from an agency sampling programme, not a prediction of the risk from your individual serving.[6]

Pasteurised cheese needs protection after treatment too. New Zealand's MPI identifies equipment, personnel and cross-contamination between raw materials and finished products as possible contamination routes for both pasteurised and raw milk cheeses. Milk treatment is one part of a wider system of hygiene and process controls.[3][16]

How Canada, Australia and New Zealand approach the cheese

In Canada, cheese from an unpasteurised source generally needs storage before sale. Food and Drug Regulations B.08.044 sets out this requirement, subject to specified exceptions. B.08.030 defines stored as held at 2 °C or above for at least 60 days from the start of manufacture. Separate exceptions cover processing ingredients and certain trade transactions.[7]

Australia's Standard 4.2.4 applies in Australia only. Alongside pasteurisation, it permits routes combining milk heat treatment with long storage of the cheese under controlled temperatures. Division 5 provides a separate pathway for raw milk cheese, with additional controls.[10]

Another route brings together heating the curd, low final moisture and a long maturation period. Think of these as parts of one process, not interchangeable temperature options.[10]

New Zealand uses MPI's Animal Products Notice: Raw Milk Products, issued on 23 June 2022 and effective from 1 July 2022. It combines processing controls and product characteristics with food safety criteria. These include absence of Listeria monocytogenes in five 25 g samples taken across a lot.[11]

At the counter, let the label start the conversation

Look for the treatment wording, and ask if it is unclear. In the EU and Great Britain, Regulation 853/2004 requires the words "made with raw milk" on products made with raw milk whose manufacturing process includes no heat treatment or physical or chemical treatment.[1][2] Canada separately requires the manufacturing start date on whole cheese from an unpasteurised source.[7]

MPI advises looking for raw or unpasteurised wording and asking staff when necessary.[16] A maker or seller can clarify the treatment. If you are following medical advice, establish the cheese type too, and consult the guidance for your country. Whether heat was used is only part of the answer.[12][13][15]

When you need extra care, look at country and cheese style

National advice differs, and several countries distinguish between cheese styles. The November 2026 summaries below explain who each piece of advice covers and what it says about raw milk cheese. For individual guidance during pregnancy or with a weakened immune system, speak to your midwife or medical team.[12][13][14][15][17]

Country	Who the advice is for	What the official advice says	Guidance date
UK	Pregnancy	The NHS lists pasteurised or unpasteurised hard cheeses, such as cheddar, gruyère and parmesan, as safe. It advises thoroughly cooking foods made from unpasteurised milk, such as soft ripened goats' cheese with a white coating on the outside, apart from the hard cheeses it lists as safe.[12]	November 2026
United States	Pregnancy	FDA advises people who are pregnant to avoid cheeses made with unpasteurised raw milk.[13]	November 2026
Canada	People at greater risk of food poisoning	Health Canada advises avoiding raw milk cheese.[14]	November 2026
Australia	Older people, pregnancy and weakened immunity	FSANZ lists raw milk cheeses as higher risk choices and pasteurised dairy as the alternative. Soft cheeses and cheeses ripened at the surface have additional advice.[15]	November 2026
New Zealand	Pregnancy	MPI advises avoiding raw milk cheeses.[16]	November 2026
France	Pregnant women, immunocompromised people, people over 65 and young children	ANSES advises avoiding raw milk cheese except cooked pressed cheeses such as gruyère or comté.[17]	November 2026

Scotland's separate restrictions on raw drinking milk concern a different product from cheese.[20] Follow the cheese advice above rather than carrying a drinking milk rule across to every dairy product. Whatever treatment you choose, look for a clear label, a properly controlled cheesemaking process and the relevant national advice.[3][12][16]

General information only, not medical advice: follow the official guidance where you live.

The Rind Question

Questions people ask

What is the difference between raw, thermised and pasteurised milk?

In the EU and Great Britain, raw milk has not been heated above 40 °C or undergone a treatment with an equivalent effect. Thermisation uses less intense heat than pasteurisation to reduce microorganisms, while pasteurisation controls susceptible pathogens during treatment.

Can raw milk cheese be heated during cheesemaking?

Yes. Raw describes the incoming milk, not the highest temperature reached by the curd later. Heating the curd is a different operation from pasteurising the milk.

Does raw milk make cheese taste better?

A treatment label does not tell you how good a cheese will taste. In one Cheddar comparison, the raw milk cheese was downgraded, while pasteurised and microfiltered cheeses were rated highly.

Does ageing raw milk cheese for 60 days make it free from pathogens?

No. The ageing period does not guarantee freedom from pathogens. Many US cheese standards require at least 60 days of curing at no less than about 1.7 °C when unpasteurised dairy ingredients are used, but the particular cheese standard determines which route is permitted.

Can I eat raw milk cheese during pregnancy?

The NHS lists pasteurised or unpasteurised hard cheeses, such as cheddar, gruyère and parmesan, as safe during pregnancy. It advises thoroughly cooking foods made from unpasteurised milk, such as soft ripened goats' cheese with a white coating, apart from the hard cheeses it lists as safe. See the NHS guidance and ask your midwife or medical team about your circumstances.

Sources

1. European Union, Regulation (EC) No 853/2004 laying down specific hygiene rules for food of animal origin, Annex I, point 4.1; Annex III, Section IX, Chapters II and IV. Supplied sheet cites the November 2024 consolidation; the live official index identifies a May 2026 consolidation. Full consolidated-text verification remains an editorial hold. Official regulation record.

2. The National Archives, Regulation (EC) No 853/2004, assimilated Great Britain text, Annex I and Annex III. Relevant extracts supplied in fromage.co.uk fact sheet A453, 6 November 2026. Live legal-text retrieval unsuccessful.

3. Codex Alimentarius Commission, Code of Hygienic Practice for Milk and Milk Products, CAC/RCP 57-2004, adopted 2004, amended 2007 and 2009. Annex II, Appendix B, thermisation and pasteurisation. Code PDF.

4. The National Archives, The Dairy Products (Hygiene) Regulations 1995, SI 1995/1086, Schedule 5, Part II, as made. Historical provision supplied in fact sheet A453. Official instrument.

5. US Food and Drug Administration, 21 CFR Part 133: Cheeses and Related Cheese Products, particularly §§ 133.3(d) and 133.113, electronic text retrieved November 2026. Regulatory text.

6. US Food and Drug Administration, Microbiological Surveillance Sampling: FY14-16 Raw Milk Cheese Aged 60 Days, content current March 2024. Sampling summary.

7. Government of Canada, Food and Drug Regulations, C.R.C., c. 870, B.08.030, B.08.044 to B.08.046, consolidated electronic text retrieved November 2026. Definitions and sale and marking provisions.

8. Hickey, D. K., Kilcawley, K. N., Beresford, T. P. and Wilkinson, M. G., Lipolysis in Cheddar Cheese Made from Raw, Thermized, and Pasteurized Milks, Journal of Dairy Science, 90, 47 to 56, 2007. Research paper.

9. McSweeney, P. L. H. and colleagues, Contribution of the indigenous microflora to the maturation of cheddar cheese, International Dairy Journal, 3(7), 613 to 634, 1993. Author institution's published abstract. Research record.

10. Australian Government, Standard 4.2.4: Primary Production and Processing Standard for Dairy Products, compilation F2021C00670, as at 3 June 2021, clauses 15 and 16 and Division 5. Official compilation PDF.

11. New Zealand Ministry for Primary Industries, Animal Products Notice: Raw Milk Products, issued 23 June 2022, effective 1 July 2022, definition 1.2 and clause 4.9. Notice.

12. NHS, Foods to avoid in pregnancy, electronic guidance retrieved November 2026. Pregnancy advice.

13. US Food and Drug Administration, Listeria (Food Safety for Moms-to-Be), electronic guidance retrieved November 2026. Pregnancy advice.

14. Health Canada, Unpasteurized or raw milk, modified 29 September 2026. Raw milk cheese advice.

15. Food Standards Australia New Zealand, Food safety for vulnerable people, electronic guidance retrieved November 2026. Vulnerable-group advice.

16. New Zealand Ministry for Primary Industries, Is it safe to drink raw milk and eat raw milk products?, official indexed text retrieved November 2026. Raw milk products advice.

17. ANSES, Fromages au lait cru : quels risques pour la santé et comment mieux les prévenir ?, 8 April 2022. ANSES advice.

18. US Centers for Disease Control and Prevention, How Listeria Spread: Soft Cheeses and Raw Milk, electronic guidance retrieved November 2026. Dairy and Listeria advice.

19. Food Standards Scotland, Dairy and eggs, electronic guidance retrieved November 2026. Scottish dairy guidance.

Last checked: November 2026

Last checked November 2026.