Modifications and Adaptations of the Charm II Rapid Antibody Assay for Chloramphenicol in Honey

The Charm II screening method for the presence of chloramphenicol in honey has a sensitivity of 0.3 ppb. This screening method is a simple, rapid antibody assay using [³H]chloramphenicol and a binding reagent. Analysis of different types of honey revealed considerable differences in results. Honey can be liquid, crystallized (creamed), or partially crystallized and is classified by the U.S. Department of Agriculture into seven color categories: water white, extra white, white, extra light amber, light amber, amber, and dark amber. Fortified and nonfortified liquid amber honey tested appropriately with the Charm II unit and the negative control provided with the unit after slight modifications were made. However, approximately 70% of creamed honey samples fortified at 0.6 ppb did not test positive for the presence of chloramphenicol using the provided negative control. Matrix quenching effects were evaluated, and these effects were accounted for by establishing different assay conditions for different honey types.