Use of antibiotics in livestock and human health concerns.

Animal feed additives have for many years constituted the largest and most controversial category of antimicrobial use. The primary concerns addressed have been the generation of antibiotic resistance in animal bacterial and the influence of such resistance on human health. Studies designed to shed light on the controversy generally have yielded information leading to ambiguous conclusions. A 1989 report from the National Academy of Sciences was the latest of a long collection of assessments that have been meant to provide expert guidance to regulatory authorities on this matter. The FDA has been trying for some time to determine whether a regulatory decision on existing products is warranted. After several decades of research directed at this question, most qualified study groups have reported a paucity of appropriate information necessary to judge the reality of a public health risk.