Zero tolerance versus zero risk

Abstract

The scientific basis and the practical implications for assigning zero tolerance are discussed for chloramphenicol, chloroform and clenbuterol. Zero tolerance for chloramphenicol and chloroform is regulated by Regulation (EC) 470/2009. The use of chloramphenicol as an antibiotic is banned in food-producing animals e.g. in the EU, USA, Canada and Australia. Yet, in some parts of the world chloramphenicol is still widely used for treatment of infections in humans; the therapeutic dosage is ca. 3.75 g/day for 5 days. Chloramphenicol can be found in the environment due to human use, but can also be produced by Streptomycetes in the soil. The zero tolerance for chloroform in foods is remarkable; it is classified as a possible carcinogen (Group 2B) but many substances with higher carcinogenic potential have been assigned maximum residue limits. In addition, humans can be frequently exposed to low levels of chloroform, depending on their activities and the quality of tap water: chloroform is formed upon hypochlorite use in swimming pools, is a residue from hypochlorite based disinfection agents, and can be formed upon chlorination of tap water. Clenbuterol has the ability to increase the muscle-to-fat body ratio, which makes its illegal use to obtain leaner meats in livestock popular. Moreover, it is also attractive for use by athletes and therefore has been banned by the World Anti Doping Agency (WADA).