Pasteurization: a key to food safety and a service FBIC provides

From an Expert's Perspective

This month, we hear from Edmund Co, Research Lead with the Food & Beverage Innovation Centre.

Before urbanization, most milk was consumed locally. This raw milk was fit for consumption because local rural consumers had adapted to the pathogens in the milk, and it wouldn’t make people sick. Throughout the early modern age, urbanization began, which saw the movement of large numbers of people to cities.  These individuals, either migrants from the countryside or born in the city, no longer had the immunity to milk pathogens that rural milk drinkers had. As a result, consumption of raw milk by these individuals often led to severe illnesses.

The solution to this was pasteurization, named after the French father of microbiology, Louis Pasteur. Pasteurization, as it applies to foods, is the application of a heat treatment to kill off pathogens. Thankfully, most pathogens are easy to kill, but as with most solutions, new problems arose.

“At the Food & Beverage Innovation Centre, pasteurization is conducted using a pilot-scale HTST pasteurizer supplied by MicroThermics, Inc., one of most versatile and useful pieces of equipment available to our clients.”
– Edmund Co, Research Lead, Food & Beverage Innovation Centre

Pasteurization used to consist of heating a large batch of milk until a certain temperature was reached. This was problematic because large vats of milk take a long time to heat up and large vats heat unevenly. The result was that the milk, though safe, had an extremely off-putting burnt flavour. Equally important was that a long heating time resulted in the loss of nutrients, such as vitamin B, from the milk. The solution was to heat small quantities of milk to a high temperature and cool the milk rapidly. This solution was known as High-Temperature, Short-Time (HTST). Unlike traditional pasteurization, which was essentially done in a large kettle, an HTST apparatus consisted of a series of metal plates with bumps and ridges (to facilitate heating). Cold milk on one side of a plate is heated to the appropriate temperature by steam on the other side of the plate. Once pasteurization is completed, the heated milk is cooled by a cooling medium. More energy-friendly arrangements ingeniously use heated milk to heat cold milk with the cold milk cooling the heated milk. By law, milk in Ontario should be heated to 63 °C for no less than 30 minutes (traditional batch pasteurization) or heated to 72 °C for no less than 16 seconds.

At the Food & Beverage Innovation Centre (FBIC), pasteurization is conducted using a pilot-scale HTST pasteurizer supplied by MicroThermics, Inc. The pasteurizer features the traditional plate arrangement characteristic of HTST pasteurizers. While most HTST pasteurizers are designed to handle fluid products, the MicroThermics pasteurizer available at FBIC can handle a wide variety of products, such as fruit juices and beverages, protein shakes, sauces, smoothies and even puddings. The MicroThermics pasteurizer can also serve as a “pre-heating” step in other food processing operations. Commonly, milk is pasteurized before it is homogenized. The MicroThermics pasteurizer not only ensures that the processed food is safe to eat but also ensures that the product can be processed further with ease. Due to this, the MicroThermics pasteurizer is one of the most versatile and useful pieces of equipment in the FBIC Beverage Pilot Plant.

Interested in learning more about our pasteurization possibilities or other innovation projects?
Explore our website, and contact David DiPietro, Research & Innovation Manager, Business Development, at [email protected].