[Code of Federal Regulations]
[Title 9, Volume 1]
[Revised as of January 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 9CFR113.29]

[Page 606-607]
 
                  TITLE 9--ANIMALS AND ANIMAL PRODUCTS
 
  CHAPTER I--ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF 
                               AGRICULTURE
 
PART 113_STANDARD REQUIREMENTS--Table of Contents
 
Sec.  113.29  Determination of moisture content in desiccated biological 
products.

    Methods provided in this section must be used when a determination 
of moisture content in desiccated biological products is prescribed in 
an applicable Standard Requirement or in the filed Outline of Production 
for the product. Firms currently using methods other than those provided 
in this section for determining the moisture content in desiccated 
biological products have until November 5, 2004 to update their Outlines 
of Production to be in compliance with this requirement.
    (a) Final container samples of completed product shall be tested. 
The weight loss of the sample due to drying in a vacuum oven shall be 
determined. All procedures should be performed in an environment with a 
relative humidity less than 45 percent. The equipment necessary to 
perform the test is as follows:
    (1) Cylindrical weighing bottles with airtight glass stoppers.
    (2) Vacuum oven equipped with validated thermometer and thermostat. 
A suitable air-drying device should be attached to the inlet valve.
    (3) Balance, accurate to 0.1 mg (rated precision 0.01mg).
    (4) Desiccator jar equipped with phosphorous pentoxide, silica gel, 
or equivalent.
    (5) Desiccated vaccine in original sealed vial. Sample and control 
should be kept at room temperature in their original airtight containers 
until use.
    (b) Test procedure:
    (1) Thoroughly cleaned and labeled sample-weighing bottles with 
stoppers should be allowed to dry at 60 3 [deg]C 
under vacuum at less than 2.5 kPa.
    (i) Transfer hot bottles and stoppers into the desiccator and allow 
to cool to room temperature.
    (ii) After bottles have cooled, insert stoppers and weigh and record 
the weights of the bottles as ``A.''
    (iii) Return weighing bottles to the desiccator.
    (2) Remove the sample container seal.
    (i) Using a spatula, break up the sample plug and transfer the 
required amount of sample to the previously tared weighing bottle.
    (ii) Insert the stopper and weigh and record the weights of the 
weighing bottles as ``B.''
    (3) Place the weighing bottle with the stopper at an angle in the 
vacuum

[[Page 607]]

oven. Set the vacuum to < 2.5 kPa and the temperature to 60 3 [deg]C.
    (4) After a minimum of 3 hours of drying time, turn off the vacuum 
pump and allow dry air to bleed into the oven until the pressure inside 
the oven is equalized with the prevailing atmospheric pressure.
    (5) While the bottle is still warm, replace the stopper in its 
normal position and transfer the weighing bottle to the desiccator.
    (i) Allow a minimum of 2 hours for the weighing bottle to cool to 
room temperature or for its weight to reach equilibrium.
    (ii) Weigh, and record the weight as ``C.''
    (6) Calculate the percentage of moisture in the original sample as 
follows:

(B-C)/(B-A) x (100) = Percentage of residual moisture, where:
A = tare weight of weighing bottle
B-A = weight of sample before drying
B-C = weight of sample after drying

    (7) The results are considered satisfactory if the percentage of 
residual moisture is less than or equal to the manufacturer's 
specification.

[68 FR 57608, Oct. 6, 2003]