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What is Pasteurization & How Does it Work?

July 16, 2019

There’s a lot of confusion around what it means to pasteurize milk and why it’s done. Here’s what you need to know. Simply put, pasteurization is the process of heating then cooling milk to eliminate potentially harmful bacteria without affecting the taste or nutritional value. Pasteurization is not bad for you, but quite the opposite. The process is intended to make milk safer to drink.

What is pasteurization?

Pasteurization is the process of heating and cooling food to kill bacteria. The process of pasteurization was invented over 150 years ago by French scientist Louis Pasteur. He found that thermal processing (in basic terms, heating) could destroy, deactive, or eliminate unwanted bacteria and pathogens.

Pasteurization does not add any chemicals or other additives to milk, nor does it remove the nutrients found in milk. It is simply a process of heating and cooling to kill harmful pathogens. It does not alter milk otherwise.

Eventually, the process made its way to the United States and into the dairy industry. It has since become an industry standard and regulation to ensure milk is safe to drink.

How does it work?

There are different types of pasteurization, but the most common is known as High-Temperature Short-Term (HTST) pasteurization, or flash pasteurization. This method extends the shelf life of milk by keeping it fresh for two to three weeks.

HTST entails heating followed by quickly cooling the milk. The chilled, raw milk is heated by passing between heated stainless steel plates until the milk reaches 161°F. It stays at this temperature for at least 15 seconds to kill bacteria before it is quickly cooled back to its original temperature (39°F).

From there, the milk is packaged and delivered to your local grocery store.

What about raw milk?

The raw milk debate is a hot topic. Raw milk is milk that comes straight from the cow. Some claim there are health benefits of drinking raw milk, but to-date these benefits have not been scientifically proven. The problem with raw milk is that it does carry potentially harmful pathogens that can make us very sick and pose serious health risks. In the state of Nevada there are no certified raw milk dairies. All Nevada milk is pasteurized. It’s transported from the farm to the processing facility, like Model Dairy, where it undergoes the pasteurization process, is bottled, and shipped to your local grocery store.

What are the benefits of pasteurized milk?

Pasteurized milk is safe, wholesome and nutritious—allowing you to feel good about the milk you and your family are consuming. With 9 essential nutrients including 8 grams of protein and only three ingredients, milk is one of the most nutrient-dense beverages you can consume. Our farmers take their responsibility to provide healthy, safe and nutritious milk very seriously. We want to keep all our Nevada families healthy and strong.

Learn more about local dairy, ask an expert, and join the conversation.

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