Comparing Pasteurization Methods

Traditional pasteurization is relatively effective at killing harmful bacteria in milk and cream. It requires that the dairy product be held at 145 degrees Fahrenheit for 30 minutes or 161 degrees Fahrenheit for 15 seconds. Most commercial dairies that use traditional pasteurization opt to bring the milk or cream to the higher temperature over a shorter period of time for the sake of efficiency.

Ultra-pasteurized milk or cream is held at 280 degrees Fahrenheit for a minimum of two seconds. It is then packaged on normal production lines and sold in the refrigerated section of the grocery store.

Dairy products labeled "ultra-high-temperature" or "UHT" have been ultra-pasteurized then packaged in a completely sterile environment using hermetically sealed containers.

Safety

Traditionally pasteurized cream is not completely sterile, but too few bacteria remain in the cream to cause illness.

Prior to opening the package, ultra-pasteurized cream is close to sterile. All bacteria present in the milk have been killed, but since it is not packaged in a hermetically sealed container, there is the possibility for bacteria to recontaminate the cream. After the container is opened, the risk of bacterial contamination is much higher.

All fresh cream, whether is has been pasteurized using traditional methods or ultra-pasteurized, should be kept in the refrigerator between 34 and 38 degrees Fahrenheit to minimize spoilage from recontamination.

UHT treated cream is packaged in a hermetically sealed container and does not require refrigeration prior to opening.

Shelf Life

Ultra-pasteurized cream will last significantly longer than cream that has been traditionally pasteurized, provided you store it in the refrigerator. Traditionally pasteurized cream has a shelf life of 10 to 21 days in the refrigerator, while ultra-pasteurized cream will last 30 to 90 days in the refrigerator, as long as it is unopened. UHT-treated cream is shelf-stable and does not require refrigeration before opening. It will last six months or more, provided the seal is not broken. Once you open a container of cream, you should consume it within a few days and store it in the refrigerator, regardless of the type of pasteurization used.

Flavor

Ultra-pasteurized cream is more sterile and has a longer shelf life than traditionally pasteurized cream, but it does have a slightly cooked flavor. If you plan to use the cream in a cooked dish, such as a sauce or cream soup, this may not be a problem. However, you may find that you prefer traditionally pasteurized cream for fresh recipes such as whipped cream.