Sulfonamide residues in pork: past, present, and future

Abstract

The Food Safety and Inspection Service (FSIS) of the U. S. Department of Agriculture (USDA) has been involved for a number of years with the problem of sulfonamide residues in pork. In the 1970s, concern was raised regarding the use of sulfonamides when food safety criteria used for premarketing approval of new animal drugs and the safety data base for sulfonamides were found to be inadequate. Regulatory analytical methods for monitoring sulfonamides were developed and put to use by FSIS. With educational efforts by government and industry, by 1980 it was thought that the problem was being solved. In the 1980s, however, the sulfonamide violation rate began to increase; the USDA strengthened its educational programs, developed a rapid test for sulfonamides and pursued regulatory initiatives. By 1987 sulfonamide violations in liver tissue (i.e., greater than .1 ppm) had declined to 3.8%; however, new toxicological information associating sulfamethazine with the development of follicular cell adenomas of the thyroid gland in rats and mice led the FSIS to begin an enhanced sulfamethazine control program in the spring of 1988. The FSIS believes that production quality assurance is the key to prevention. The Agency's initiatives toward this end are designed both to encourage industry accountability and to provide disincentives for violators. The current approaches to the sulfonamide problem hold the clear promise of a satisfactory solution.