milk cartons

Why do certain containers of cow’s milk have a longer expiration date?

Every Sunday after Church, I head to our local grocery store with my weekly shopping list. Some weeks I’m more prepared then others but one thing that is always on my list is milk. I have mentioned in previous posts that grocery shopping should not be stressful; however, with all the food labels out there, how can it not be? Choices are great and signs of a healthy market, but I don’t believe that being overwhelmed should be one of the side effects. You might have noticed on milk labeling that certain containers of cows’ milk have a longer shelf life. How does this milk not spoil?

The quick answer has to do with two different pasteurization techniques. The milk either undergoes high-temperature, short-time, (HTST) pasteurization or ultra-high temperature pasteurization (UHT) for a longer term shelf life. Before I describe the two most common pasteurization methods, let me briefly explain the pasteurization process.

Pasteurization is an important process that ensures that milk and dairy products are safe for everyone to consume. According to the Grade “A” Pasteurized Milk Ordinance,¹ pasteurization is the process used to kill bacteria without affecting the taste or nutritional value of milk. The Ordinance defines pasteurization as heating every particle of raw milk or milk product, in properly designed and operated equipment, to a certain temperature for a specific period of time.¹ The dairy industry, the Center for Disease Control along with the Food and Drug Administration (FDA) along with many other health and scientific organizations strongly support the pasteurization of milk. You can read the FDA’s position statement here.

What are the differences between HTST and UHT then?

High temperature, short time (HTST) pasteurization – or traditional pasteurization:

  • Heats the milk to a required minimum temperature of 72◦C (161◦F) for at least 15 seconds.¹
  • Removes 99.9% of the bacteria in the milk.
  • On average, dairy processors recommend HTST milk be consumed eighteen (18) days from the date it is bottled.

Ultra high temperature pasteurization (UHT) or ultra-pasteurization (UP):

  • The milk has to be thermally processed at or above 138◦C (280◦F) for at least two seconds.¹
  • The process eliminates a larger percentage of bacteria than HTST pasteurization.
  • On average, dairy processors recommend UHT milk be consumed sixty (60) days from the date it is bottled.

How does organic milk stay fresh for so long? The shelf life for organic milk actually has nothing to do with the milk being organic. The extended shelf life (seen in both organic and conventional milk) is because of the pasteurization process. Organic products are not as commonly produced, so they often have to travel further to reach store shelves. All milk and dairy products (regardless if it is conventional or organic) are antibiotic free and I have posts dedicated to just this topic, click here to read more or here.

At our house, we don’t have any problem going through 2 gallons of 2% milk weekly, but if you are looking for milk with a longer shelf life, I would highly recommend you buy UHT milk.

We are proud to be in the dairy industry for many reasons. It not only takes food safety very seriously, but it also supports consumer choice. The bottom line is that carton to carton, bottle to bottle, all milk is wholesome, safe, and nutritious.

Originally posted on Mackinson Dairy.

Mary Faber

About Mary

My family raises dairy cows in Pontiac, IL. Milk from our farm ends up in bottles of Prairie Farms milk you can buy at your local grocery store.

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