The History of Pasteurisation: How Boiling Milk Saved Millions from Deadly Food Poisoning

Can you imagine drinking milk which has not been pasteurised? Pasteurisation is a mild heat treatment that is used to kill harmful germs in food and drinks. Did you know that the process is named after French scientist Louis Pasteur, who first demonstrated it in the 1860s? Today, we will delve deeper into the fascinating history of milk pasteurisation.

Timeline: A Look into The History of Pasteurisation

A 2025 study, published in the Foods journal, shared the brief history of milk pasteurisation. Let us take a look at it:

Louis Pasteur’s Invention

The concept of food preservation by heating started in 1809 when Nicolas Appert introduced the appertization process. Later, French chemist and pharmacist Louis Pasteur created a theoretical framework explaining how heat kills spoilage microorganisms. By 1863, Pasteur had applied this heating technique to solve spoilage issues in wine and beer. This process of heating liquids to specific temperatures to kill microbes eventually became known as pasteurisation. 

Campaign to Promote Milk Pasteurisation 

In 1889, Strauss and Monrad started a campaign to promote milk pasteurisation throughout the United States. During the same year, the connection between raw milk consumption and the transmission of animal pathogens to humans was also established. Moreover, milk pasteurisation quickly gained popularity in Denmark as a crucial step to reduce the risk of spreading tuberculosis. 

First Commercial Milk Pasteurisation Tool

In 1891, Sheffield Dairy Farms installed the first commercial milk pasteurisation equipment in the USA. This initiative for public health led to the first law mandating milk pasteurisation in Chicago in 1909. 

Since then, pasteurisation has been adopted as a standard and important practice in the commercial dairy industry worldwide. The main aim of pasteurisation is to eliminate harmful pathogenic bacteria, while also reducing spoilage bacteria. 

First Commercial Milk Pasteurisation Plant 

According to the Encyclopedia Britannica, the first commercial milk pasteurisation plant was established in the US in the early 20th century by the physician and public health activist Charles North. It used the low-temperature–long-time (LTLT) process, which is still used in small processing units where the yield is typically less than 1,000 liters (264 gallons) per hour. 

More modern techniques consist of continuously passing milk from a storage tank through a series of heat exchangers (thin metal plates), which typically heat the milk to 72 °C (162 °F) for 15 seconds. This is followed by rapid cooling to 4 °C (39 °F). This technique, used in continuous flow operations, is known as high-temperature–short-time (HTST) pasteurisation. It is suitable for large-scale, commercial units that process more than 5,000 litres (1,320 gallons) of milk per hour on average. 

Importance of Milk Pasteurisation

As per the aforementioned study, pasteurisation destroys microbes, thereby significantly extending the shelf life of milk. These heating techniques successfully eliminate over 99.9% of dangerous vegetative pathogens such as E coli, Salmonella, and Listeria. 

The main target of standard pasteurisation is to eliminate the most temperature-resistant pathogens such as Mycobacterium tuberculosis. While pasteurisation guarantees milk safety, it does not destroy all heat-resistant bacterial spores, which needs higher sterilisation temperatures. 

Despite modern alternatives, traditional thermal pasteurisation is still the most vital tool in preventing deadly food poisoning from dairy. Today, this simple yet revolutionary boiling technique continues to save millions of lives by making milk a safe staple food. 

Conclusion

The history of pasteurisation focuses on a monumental leap in food safety, transforming raw milk from a potential health hazard into a reliable, nutritious staple. Today, Louis Pasteur's revolutionary heating technique remains an important global practice, continuing to protect millions of people from deadly foodborne illnesses every day.