[Code of Federal Regulations]
[Title 21, Volume 1]
[Revised as of April 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR500.84]

[Page 13]
 
                        TITLE 21--FOOD AND DRUGS
 
CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN 
                          SERVICES (CONTINUED)
 
PART 500--GENERAL--Table of Contents
 
 Subpart E--Regulation of Carcinogenic Compounds Used in Food-Producing 
                                 Animals
 
Sec. 500.84  Operational definition of ``no residue''.

    (a) On the basis of the results of the chronic bioassays and other 
information, FDA will determine whether any of the substances tested are 
carcinogenic.
    (b) If FDA concludes that the results of the bioassays do not 
establish carcinogenicity, then FDA will not subject the sponsored 
compound to the remainder of the requirements of this subpart.
    (c) For each sponsored compound that FDA decides should be regulated 
as a carcinogen, FDA will analyze the data from the bioassays using a 
statistical extrapolation procedure.
    (1) For each substance tested in separate bioassays, FDA will 
calculate the concentration of the residue of carcinogenic concern that 
corresponds to a maximum lifetime risk to the test animal of 1 in 1 
million. FDA will designate the lowest value obtained as So.
    (2) FDA will consider that ``no residue'' of the compound remains in 
the edible tissue when conditions of use of the sponsored compound, 
including any required preslaughter withdrawal period or milk discard 
time, ensure that the concentration of the residue of carcinogenic 
concern in the total diet of people will not exceed So. 
Because the total diet is not derived from food-producing animals, FDA 
will make corrections for food intake. FDA will designate as 
Sm the concentration of residue of carcinogenic concern that 
is permitted in a specific edible product.