UNITED STATES DEPARTMENT OF AGRICULTURE
Consumer and Marketing Service
Fruit and Vegetable Division
Processed Products Standardization

and Inspection Branch

: FOR USE OF USDA : A ~ 412
sPROCESSED FOOD INSPECTORS:

“ae September 1967
TO: All Processed Food Inspectors

FROM: Fred Dunn, Chief of the Branch

SUBJECT: Frozen Whole Kernel Corn -~
Evaluation of Tenderness and Maturity

I PURPOSE AND’ SCOPE ceo

The evaluation of the factor of "Tenderness and Maturity”
in frozen corn continues to challenge the expertise of
inspection personnel’! ! This instruction is not intended to
solve the entire problem but will promote greater objec—
tivity to the inspector's judgment.

Ir INSPECTION PROCEDURE
Follow these steps in evaluating tenderness and maturity:

1) Thaw the frozen corn in accordance with the Branch
instructions.

2) Select a representative sub-sample (about 100 kernels)
and apply the "squeeze" test. :

3) Classify the kernels into the following categories:

Pre-miik or blister
Milk .

Early cream

Cream

Early dough

Dough.

4) Determine the tentative grade classification and
tentative score point based upon the squeeze test
keeping in mind that for --

Grade A —- Milk or Early Cream
Grade B -- Cream
Grade C -- Early Dough to Dough.

Distribution - A -- See reverse side --

Agriculture ~ Washington


Tit

5) Adjust the tentative score point within the appropriate
grade according to the results of the squeeze test. For
example, in Grade A if the kernels are predominantly
in the milk stage the sample unit should receive a higher
tentative score than if they: are predominantly in the
early cream stage. The score is adjusted downward
depending upon the number of kernels in the next lower
grade classification as per the scoring guide in this
instruction.

6). Gonfirm tentative grade and score point by cooking a
representative number of samples. This is very important
since the effect of pericarp can best be determined on
the cooked sample. The testing of cooked samples will
also confirm the inspector's judgment in classifying
individual kernels into the proper maturity level.

7) If evaluation of the cooked sample does not confirm the”
squeeze test, adjust the score point and grade based on
the cooked sample. This is the way the consumer is going
to use the product and should be the final test as far as
the tenderness and maturity score is concerned.

8) Whenever practical check samples according to the tri-
metric test (see memorandum A-155). Although this
procedure is time consuming and requires good laboratory
technique, it tends to -prottote uniformity of inspection
results.

SCORING GUIDE

In most seasons it is difficult to control the harvesting

to the point that all the corn delivered will be reasonably
uniform’ maturity. Consequently, occasional kernels of lower
quality will be found in some of the sample units. Therefore,
allow a maximum of 10% by count of kernels of the next lower
grade than that grade ¢lassification indigatéd by the squeeze
test. For example, in the Grade'A classification allow a
maximum of 10% kernels that may be in the cream stage, sub-
ject to verification by the cook test.

The presence of pre-milk or blister corn is undesirable in
all the grade classifications. Consequently ‘the score and
probably grade must be lowered when significant number of
blister (water) kernels are present.

As a guide, permit a maximum of blister kernels ~~
In Grade A 15% by count

In Grade B 25% by count
In Grade C -~ 50% by count.