What is unpasteurised dairy? Risks, nutrition, and food safety

October 24, 2025 •

3 min read

According to the CDC, from 1998 through 2018, there were over 200 outbreaks linked to unpasteurised milk, sickening thousands. Understanding what is unpasteurised dairy is crucial for making informed decisions regarding milk and other dairy products, particularly for high-risk groups.

Quick Summary

Unpasteurised dairy is milk that has not been heat-treated to kill harmful pathogens. The production and consumption of this raw milk carry significant risks of foodborne illness due to contaminants like E. coli, Salmonella, and Listeria, without offering proven nutritional superiority.

Key Points

Definition: Unpasteurised dairy, or raw milk, is milk that has not been heated to kill bacteria, unlike pasteurised milk.
Food Safety Risk: Raw milk poses a significant risk of foodborne illness from pathogens like E. coli, Salmonella, and Listeria, which can lead to severe or life-threatening health issues.
No Proven Nutritional Advantage: Contrary to popular belief, pasteurised and unpasteurised milk have no meaningful difference in essential nutrient content; pasteurisation does not significantly diminish nutritional value.
Vulnerable Populations: Children, the elderly, pregnant women, and individuals with weakened immune systems are particularly susceptible to the severe consequences of consuming raw dairy.
Legality Varies: Regulations for the sale and distribution of unpasteurised dairy products differ significantly by region, and it is illegal for interstate commerce in the US.
Raw Milk Cheese: Certain cheeses can be made from raw milk, but regulations often require specific aging periods to reduce bacterial risk.

Understanding unpasteurised dairy

Unpasteurised dairy, also known as raw milk, is milk that has not undergone pasteurisation, a heat-treatment process to eliminate disease-causing bacteria. This means raw milk can contain various bacteria, some of which are harmful. While proponents suggest raw milk has nutritional advantages and better flavor, public health organizations caution about the significant health risks associated with potential contamination.

The pasteurisation process

Pasteurisation involves heating milk to specific temperatures for a set time to kill harmful bacteria. High-Temperature Short-Time (HTST) pasteurisation, a common method, heats milk to at least 71.7°C (161°F) for 15 seconds. This process effectively kills pathogens without significantly altering the milk's nutritional content, taste, or texture. Ultra-High Temperature (UHT) pasteurisation uses even higher temperatures for a shorter time, extending shelf life significantly.

Significant food safety risks

The main concern with unpasteurised dairy is the risk of contamination by dangerous bacteria, which can occur during milking or from the animal itself. The CDC has linked numerous foodborne illness outbreaks to raw milk. Common bacteria found in raw milk include:

Campylobacter: Causes gastrointestinal symptoms.
E. coli O157:H7: A severe strain that can cause kidney failure.
Listeria monocytogenes: Particularly dangerous for pregnant women and newborns.
Salmonella: Leads to fever, diarrhea, and cramps.

Vulnerable populations like children, pregnant women, the elderly, and those with weakened immune systems face higher risks of severe complications. Recent concerns also include the potential for viruses like H5N1 avian influenza in raw milk.

Nutritional content vs. health risks

Despite claims of superior nutrition in raw milk due to enzymes and probiotics, scientific studies show no significant difference in essential nutrients compared to pasteurised milk. Any minimal loss of heat-sensitive vitamins during pasteurisation is easily offset by a balanced diet. The potential severe health consequences of raw milk contamination far outweigh any unproven benefits.

Unpasteurised dairy products and legality

The sale of unpasteurised fluid milk is prohibited in many areas, including interstate commerce in the US. However, regulations for unpasteurised products like cheese vary. Some regions allow raw milk cheese sales if aged for a specific period, typically 60 days, as this process can reduce bacterial risk. Still, public health advice suggests high-risk individuals avoid soft unpasteurised cheeses. The legality and availability of raw milk products depend on location and type. For further information, the Food and Drug Administration provides guidance on the risks of raw milk [https://www.fda.gov/food/buy-store-serve-safe-food/dangers-raw-milk-unpasteurized-milk-can-pose-serious-health-risk].

Comparison of Unpasteurised and Pasteurised Dairy


Feature	Unpasteurised (Raw) Dairy	Pasteurised Dairy
Processing	Unheated or minimally heated.	Heat-treated to kill bacteria.
Food Safety	High risk of harmful bacteria.	Low risk of harmful bacteria.
Nutritional Content	No significant difference in essential nutrients compared to pasteurised milk.	Retains essential nutrients.
Flavor Profile	Described as richer by proponents.	Consistent, mild flavor.
Shelf Life	Shorter shelf life.	Extended shelf life.
Legality	Highly regulated; varies by location.	Widely available and often legally mandated for commercial sale.

Conclusion

While some find unpasteurised dairy appealing due to minimal processing, the scientific evidence highlights significant safety concerns. Pasteurisation is a safe method to consume milk without losing essential nutrition. The risk of serious illness from unpasteurised dairy, particularly for vulnerable groups, outweighs unproven benefits. Public health experts recommend pasteurised dairy for safety.

Potential raw milk products to avoid

Raw Fluid Milk: Highest risk.
Soft Cheeses: Higher risk if unpasteurised.
Raw Cream, Yogurt, and Ice Cream: Can carry the same pathogens as raw milk.

High-risk groups should be cautious

Pregnant Women: High risk for Listeria.
Infants and Young Children: Vulnerable to severe infections.
Older Adults: Higher risk due to compromised immune systems.
Immunocompromised Individuals: Increased risk.

Frequently Asked Questions

Unpasteurised dairy is considered a risk because it can harbor harmful bacteria, such as Salmonella, E. coli, and Listeria, which are not killed by heat treatment. These pathogens can cause severe foodborne illnesses.

No, pasteurisation does not meaningfully reduce milk's nutritional value. Studies show that essential nutrients like calcium and protein remain intact, and any minor loss of heat-sensitive vitamins is not significant.

While the aging process for some hard, unpasteurised cheeses (like Parmigiano-Reggiano) helps reduce bacterial risk, soft cheeses made with raw milk still pose a significant threat. Public health advice recommends high-risk groups avoid all unpasteurised cheese, especially soft varieties.

Even with meticulous hygiene on the farm, contamination is still possible and unpredictable. No farmer can guarantee that raw milk is completely free of harmful bacteria. Public health organizations advise against consuming raw milk regardless of its source.

Individuals at high risk for serious complications should avoid unpasteurised dairy. This includes pregnant women, infants and young children, older adults, and people with compromised immune systems.

The primary difference is the heating process. Pasteurized milk is heated to kill pathogens, making it safe for consumption, while raw milk is not. This difference accounts for the vastly different food safety profiles.

Reputable products will be clearly labeled as 'pasteurised,' 'unpasteurised,' or 'raw milk' on the packaging. If the label doesn't specify, it is generally assumed to be pasteurised for products sold in stores.