Tuesday, February 1, 2011

Nanny Tip-Freezing your Food at Home

There are a few ways that fruits and vegetables can be frozen to improve their quality.  In the food industry a number of products will be used which are labeled as “IQF” which means “individually quick frozen.”  For example, to individually quick freeze something like berries, you would take fresh berries, and lay them out in a single layer on a cookie sheet or other long thin pan, and freeze them prior to putting them together in a freezer bag.  This way, the berries are frozen, but they aren’t frozen into a big clump that needs to be thawed prior to using some of the berries.  This is of benefit since only those berries you want to use are used and the rest remain frozen, with no decrease in quality.

I prefer the IQF method, but you can always freeze peas or berries or corn, after blanching, as one big bag, not individually.  Blanching is the method where fresh fruits or vegetables are dipped in boiling water for a few seconds to kill surface bacteria and stop or slow enzyme activity.  Once a food is picked, enzyme activity will eventually lead to its demise (like a banana or avocado turning brown).  The main problem with freezing as a full bag, and not individually, is that it freezes slower.  With cooked foods that you are freezing, this can be a problem as it takes the middle of the food hours longer than the outside to freeze, and can allow bacteria a few hours longer to grow before they are frozen.  When the food is thawed, the bacteria wake up and start multiplying again until the food can be cooked or reach an internal temperature of 140 °F (60°C).

Basically, the rule of thumb for freezing is that you want to take your foods from cooked or room temperature down to completely frozen in the shortest amount of time possible.  How do you do this?  Freezing the food in the smallest portions possible will lead to shorter freezing times.  It takes a lot less time to freeze 1 berry than it does to freeze a gallon of berries.  Blanching is essential for some foods, mostly vegetables or fruits that don’t last very long once picked.  Freezer bags are essential.  They block moisture passing out of the bag and oxygen passing into the bag, which leads to freezer burn.  Other regular bags do not.  Remember, most foods will survive the freezing process, so freeze your foods in as small of portions and as fast as possible and they’ll last a lot longer and taste so much better.


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