HOMOGENEOUS SAMPLE PREPARATION OF RAW SHRIMP USING DRY ICE

Sample homogeneity is critical to accurate and reproducible analysis o f trace residues in foods. A method of uniform sample preparation usin g dry ice is described for shrimp. Other sample preparation techniques for raw shrimp produce nonhomogeneous samples. Sample homogeneity was determined through analysis of chloramphenicol added to intact tiger or white shrimp prior to sample preparation. Simulated chloramphenicol residue levels were 50, 15, 10, and 5 ppb. No significant differences were noted when analyses of shrimp inoculated with chlor-amphenicol p rior to sample preparation with dry ice were compared with analyses of shrimp spiked after grinding with dry ice. Grinding shrimp with dry i ce produced samples with homogeneous chloramphenicol residues. This te chnique should be applicable to other tissues and vegetable products.