Major scientific results from the T-TT program
Although frozen-food research had begun long before the initiation of
the T-TT program, it had been carried out by a variety of groups both
in industry and academe. The useful information obtained prior to 1948
was fragmented with many unanswered questions. The WRRC program was the
first large-scale systematic investigation of the problems of delivering
a quality product from the farm to the consumer, in a fashion that would
keep the consumer interested in making future purchases. Among the innovative
results emanating from the WRRC work were:
Generating practical working models for a large variety of frozen
Predicting the stability and quality of frozen food over time by
using mathematical equations.
Discovering that 0°F is the critical temperature to maintain
stability in most frozen foods, a result that is still followed today
in most household freezers.
Recommending to the transportation industry the maximum time different
food types could be warmed above 0°F without significant deterioration.
Identifying specific aroma compounds for a wide variety of foods.
Establishing analytical methods for measuring "quality."
Establishing the stability periods for frozen foods, leading to
a star marking system often used to help the consumer know how long a
particular food can remain in cold storage before it begins to deteriorate.
Inventing "dehydrofreezing," wherein certain foods, such
as potatoes, are partially dehydrated before freezing, resulting in financial
savings because of reduced volume and weight.
Improving the blanching process for the preparation of frozen vegetables,
including the Individual Quick Blanching (IQB) and the Vibrating IQB cooler.
Discovering that for some foods, notably orange juice and onions,
the addition rather than the removal of an enzyme was important for quality
Eliminating salmonella contamination in fresh and frozen liquid
The T-TT work investigated a complex process, and produced complex results.
As it progressed, the frozen food industry quickly accepted its results
and adopted its recommendations. Any scientific investigation also inevitably
generates as many new questions as it answers. In a 1968 book, Van Arsdel
commented, "in the following chapters (5)
the reader will find puzzles and unanswered questions; every such question
should be looked upon as an opportunity, a door which only needs to be
unlocked." Thus the T-TT work led to another level of research still
conducted today by a variety of groups in many different locations.
"One generalization apparent from work on this project and from published
reports by others is that the quality and acceptability of frozen foods
are eroded away by every experience, whether it be holding for a long
time at even a "good" temperature or experience of a higher
temperature for even a short time, and that the erosion is progressive
and irreparable. Frozen foods have a memory for adverse experiences."