How Does Milk Pasteurization Work?
Milk is one of the most highly regulated and carefully handled foods in the United States and for good reason. Before it ever reaches the grocery shelf, it goes through a critical step called pasteurization. This process involves heating milk to specific temperatures for set periods of time to kill harmful bacteria, which makes the milk safe to drink and extends its shelf life. It’s a standard step on New York dairy farms and in processing plants across the country, and a key reason why our dairy supply is both fresh and safe.
What Is Pasteurization?
Pasteurization is a heat treatment process. It’s designed to destroy potentially dangerous pathogens, like Listeria, Salmonella, and E. coli, without affecting the taste, texture, or nutritional value of milk. The process doesn’t sterilize milk, but it reduces bacteria to levels that are considered safe for consumption. The goal is to make milk safer, while still preserving the qualities that make it fresh and flavorful.
Types of Milk Pasteurization
There are a few different methods used to pasteurize milk, and each one uses heat and time a little differently:
HTST – High-Temperature, Short-Time
This is the most common method used in New York and throughout the United States. Milk is heated to 161°F for at least 15 seconds, then rapidly cooled. It’s efficient, effective, and ideal for large volumes of milk moving through commercial processing plants.
VAT (or LTLT) – Low-Temperature, Long-Time
This method involves heating milk to 145°F and holding it for 30 minutes. It’s typically used for smaller batches of milk, especially by artisan dairies or specialty processors.
UHT – Ultra-High Temperature
UHT heats milk to 280°F for just a couple of seconds. This process allows the milk to be shelf-stable for several months without refrigeration, though it may have a slightly different taste. It’s often used for single-serve cartons or milk sold in regions with limited cold chain infrastructure.
The Equipment That Makes It Happen
Behind every glass of pasteurized milk is a carefully designed system of tanks, piping, and heat exchangers.
Balance Tanks hold raw milk and help regulate flow into the system.
Heat Exchangers are used to bring milk up to and back down from pasteurization temperatures quickly and efficiently.
Holding Tubes ensure milk stays at the correct temperature for the exact time required.
Flow Diversion Valves automatically route milk back to be reprocessed if it doesn’t meet the time and temperature standards.
These components work together to maintain precise conditions and ensure every drop of milk is treated safely and consistently.
A Walkthrough of the
Pasteurization Process
Raw milk enters the processing facility and is stored in a balance tank.
Milk flows through a heat exchanger, where it is pre-warmed.
It moves through the heating phase, reaching the target temperature (HTST, VAT, or UHT depending on the system).
Milk holds at that temperature for the designated time.
Cooled rapidly in another section of the heat exchanger.
If it passes all checks, it moves forward to be packaged. If not, it’s rerouted.
Packaged, refrigerated, and ready for delivery.
Why It’s the Standard in New York
Pasteurization is required by law in New York. New York State takes dairy safety seriously, and the pasteurization process plays a key role in protecting public health and ensuring consumer trust. New York is one of the top dairy-producing states in the country, and our commitment to quality starts with the milk itself. By using pasteurization, New York dairy farms and processors deliver a product that’s not only delicious, but also meets the highest standards of milk safety.
Resources:
Dairy4Good – Processing Milk Section