In the early
years of frozen food, a whole host of complaints poured in about things like
cardboard texture, funny color, and no taste. Some people also worried about
lost nutrients and bacterial contamination during processing and
Then ARS scientists began the
Time-Temperature Tolerance Project. Building their own freezing facilities
inside their lab, scientists experimented with every step in the process, from
selection of the variety grown to harvesting, handling, blanching, freezing,
packaging, storing, and transporting products to market.
What these scientists learned helped
immeasurably to ensure the survival and growth of the U.S. frozen food
In time, they devised nine principles for
freezing vegetables. Producers still follow these cardinal rules today.
The Nine Principles for Freezing
1. The product must be freezable. Peas
freeze; cucumbers do not.
2. The variety must be suitable. Garden
peas, for example, freeze better than peas grown for canning.
3. The raw product must be first-class.
Freezing preserves defects as well as superior quality.
4. Handling between field and plant must be
as prompt as possible.
5. Natural enzymes must be inactivated by
6. Freezing must be fast enough to ensure
quality, yet economical enough to be competitive.
7. The plant must be kept sanitary and the
line clean to prevent contamination by molds, yeasts, and bacteria.
8. Packaging must ensure that no moisture is
lost during a year's storage.
9. Storage temperatures must be uniform, and
never, never exceed 0 degrees F.