Frozen food jokes are always fun:

• "You know what I do when I get scared by frozen food? Ice cream!"

• "I made the mistake of biting into some half-frozen food. Then I realized doing that wasn't very well thawed out."

Amusing, but freezing veggies and fruit is no joke. It's smart.

Vegetables lose 15% to 77% of their vitamin C within a week of harvest, according to a paper in the Journal of the Science of Food and Agriculture. Fruits lose their vitamin C as well. And a wide range of other important nutrients disappear from most produce somewhere between being picked, shipped, distributed, put on grocery store shelves, and kept in your fridge.

By contrast, studies show that most well-frozen fruits and vegetables go through little change in nutrient content. For instance, fresh spinach loses only 30% of its vitamin C after 12 whole months if it's frozen to -4 F.

Here’s what you need to do:

1. Wash and dry whole berries or fruit slices and spread on a sheet pan so they are not touching. Put them in the freezer until hard.

2. For veggies like beans or broccoli, wash, trim and blanch in boiling water, dry with paper towels, and chill in the fridge.

3. Then put fruit and vegetables in plastic bags; extract all air and seal tightly to avoid freezer burn.