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 that 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 Ordinancepasteurization 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 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.
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A few of the products that undergo high temperature, short time, or HTST pasteurization.

  • 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 kills any bacteria found in the milk.
    • On average, dairy processors recommend UHT milk be consumed sixty (60) days from the date it is bottled.

Milk that undergoes UHT pasteurization clearly identifies this on the product’s package.

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 and 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 though is that carton to carton, bottle to bottle, all milk is wholesome, safe, and nutritious.0606

Reference

  1. U.S. Department of Health and Human Services, Public Health Service, Food and Drug Administration. Grade “A” Pasteurized Milk Ordinance…2009 Revision. Washington, D.C.: USDHHS, PHS, FSA. May 15, 2002. http://1.usa.gov/1GGb6yS Accessed April 29, 2015.

About Mary Faber

Mary Mackinson Faber of Pontiac, Illinois serves as the Controller for Graymont Cooperative Association. Mary also manages her family’s dairy and grain farm’s social media presence. Mary’s goal is to start a conversation between people who grow and produce food and the people buying it. Mary received her bachelor’s degree in Agriculture Business and Master of Business Administration from Illinois State University. She and her husband, Jesse, have two children. Mary and Jesse are the 2015 Excellence in Agriculture Award winners for Illinois and were runners-up for the American Farm Bureau Federation (AFBF) Young Farmers & Ranchers Excellence in Agriculture Award.

Comments

  1. Thanks for that clarification. My wife and I don’t go through milk very fast so I’d certainly prefer the UHT. I’ll have to see if my stores carry that for the conventional milk I prefer

  2. Rick Leonard says:

    This is a great site and I am bookmarking it. I appreciate the explanation regarding how milk shelf life is affected by pasteurization method.

    As a kid, one of my chores was daily milking. We were not in the dairy business but had a cow for our own household consumption. Occasionally, we would run the milk through a cream separator and sometimes hand churn the cream into butter. My mother religiously pasteurized any milk for consumption or cooking in a device that resembles slow cookers. I do recall that a fair amount of milk tended to get thrown out even with pasteurization, but because we had daily fresh supply for much of the year, shelf life was not that critical.

    I am wondering what the average shelf time for raw milk is? The theory with raw milk is that milk is naturally free of pathogens and harmful items are only added during processing. If you raise animals on “clean pastures”, and avoid stresses on animals, pasteurization is essentially unnecessary. But I presume it is bacteria that spoils milk and I know from personal experience that raw milk has a much shorter shelf life.

  3. Denis Ward says:

    Additionally, the third method of pasteurizing milk is called Vat pasteurization. It is the original method. Milk is heated to 145 degrees and held for 30 minutes. It is then cooled and bottled. It usually has a 16 day code. Some products, cream and flavored milk, have to be heated to 150 or 155 degrees and held for the 30 minutes. Generally this process will not change the structure of the milk as much as the higher temperature pasteurizing so the flavor is closer to fresh from the cow. All methods retain the natural nutrition and goodness of milk.

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