Validation of Delvotest® Fast BT for Detection of β-Lactams and Tetracyclines in Raw Cow's Milk: Performance Tested MethodSM 102104.

Abstract

Delvotest® Fast BT is a rapid test for qualitative detection of β-lactams and tetracycline residues in raw, comingled cow's milk. The test kit was validated under the AOAC Performance Tested MethodSM certification program. Detection capabilities of penicillin G and tetracycline residues were determined. Also, the test method ruggedness, cross-reactivities, interference and masking effects by other antibiotic residues, influence of bacterial and somatic cells, product consistency, and stability of the test kit were studied. The test cassette is placed in the specially designated incubator (Delvotest® Fast Start III), the milk sample is added to the loading site, and the cassette is incubated for 7 min at 50°C. The test result is read instrumentally using a specially designated reader (Delvotest® Fast Go Max). Measurements in the method developer study and subsequent confirmation during independent laboratory study showed detection capabilities of 2.1 ppb penicillin G and 95 ppb tetracycline. Regarding robustness, no false positives nor false negatives were found in the method ruggedness, cross-reactivity, masking, and interference studies. In addition, the test performance is not affected by a high number of bacterial or somatic cells present in the milk sample. Stability studies demonstrated good performance of the kit during the shelf life of 12 months. The validation study demonstrates that Delvotest® Fast BT conforms to the product performance claims and confirms the robustness of the test toward small variations in the operation parameters and normally expected variations in milk samples. Delvotest® Fast BT provides users in the entire milk flow logistics from grass to glass (e.g. farmers and dairies) with a rapid and easy to use method for qualitative detection of β-lactams and tetracycline residues in raw cow's milk.