Raw milk and raw-milk products can affect our health in both positive and negative ways. A study conducted by Agroscope summarises current findings from the research literature and classifies the positive effects and risks.
Today, we know that the bacteria in the human gut affect us in a number of ways: in addition to performing an immunological function, synthesising vitamins, and breaking down dietary fibre, they possess metabolic properties involved in the prevention of obesity and cardiovascular diseases. They even influence our mental health. For all these functions, it is essential to have a gut microbiome that is as varied as possible. Any diet that supports this diversity also encourages good health. Because of their high microbial diversity, raw milk and raw-milk products have a positive effect on gut microbiome diversity.
The sale and consumption of raw milk are regulated by law
Pursuant to Swiss food legislation, raw milk may not be advertised or offered for direct consumption. The point of sale (Fig.1) is required to provide information on the shelf-life, storage conditions and treatment of raw milk:
- Store at 5 °C or less
- Heat to at least 70 °C before consuming
- Consume within 3 days
In Switzerland, dispensing with heat treatment is therefore the personal responsibility of the consumer.
Differences between raw milk and heat-treated milk
The primary aim of heating milk is to reduce its bacterial content and ensure microbiological food safety. As a side effect of the heating process, however, heat-sensitive components of the milk are altered in a variety of ways. Because of the reduced microbial diversity and changes in the heat-sensitive components, various positive health effects of the raw milk, such as protection from allergies, are weakened or even completely lost. Production-related differences such as e.g. the higher omega-3 fatty-acid content are also significant. The effects on our health are long-term and multifactorial in nature, making them very difficult to document and quantify. The risks, however, often involve rather short-term effects with an obvious cause, such as e.g. microbial food poisoning. It is important not to overestimate the negative effects and underestimate the positive effects.
- The consumption of raw-milk products supports gut microbiome diversity and protects us from allergies, thus promoting good health.
- Heat-treated milk contains fewer bacteria – both health-promoting and problematic types – than raw milk, and thus ensures microbiological food safety.
- Heating the milk not only reduces microbial diversity, however, but also alters heat-sensitive components that have a positive effect on health.
- Certified raw-milk products (e.g. Vorzugsmilch in Germany or raw-milk cheeses) can retain many valuable properties of the raw milk while at the same time complying with food-safety requirements.
- The production of raw milk and raw-milk cheese is a complex system requiring inter alia well-trained professionals, healthy, infection-free herds, a trustworthy HACCP1 concept, validated hurdle technology2, and strict inspections carried out by the government or the private sector.
1 HACCP (Hazard Analysis by Critical Control Points) is a hygiene concept applied in food manufacture and distribution and in the hospitality and catering sector. HACCP seeks to guarantee food hygiene and safety by preventing food hazards that could lead to consumer illness or injury.
2 Hurdle technology is a food-technology preservation process ensuring the hygienic safety of foods.