Validation of the RIDASCREEN(®)FAST Milk Kit

• Published in: Journal of AOAC International 2016-03, Vol.99 (2), p.495-503
• Main Authors: Weiss, Thomas, Lacorn, Markus, Flannery, Jonathan, Benzinger, M Joseph, Bird, Patrick, Crowley, Erin S, Goins, Dave, Agin, James R, Gilani, Sarwar, Poepping, Bert, Garber, Eric
• Format: Article
• Language: English
• Subjects: Animals; Caseins - analysis; Chemical properties; Enzyme-Linked Immunosorbent Assay; Food Analysis; Food testing equipment; Identification and classification; Lactoglobulins - analysis; Milk - chemistry; Milk proteins
• ISSN: 1060-3271; 1944-7922
• DOI: 10.5740/jaoacint.15-0290

The RIDASCREEN(®)FAST Milk test is a sandwich ELISA for the rapid quantification of milk proteins in various foods. The specific antibodies target casein and β-lactoglobulin. Samples are extracted and can then be analyzed in less than 40 min. The calibration curve covers a range from 2.5 to 67.5 mg/kg milk protein. The assay was validated with cookies, infant formula, chocolate dessert, ice cream, and sausages. All negative samples were found well below the LOQ of 2.5 mg/kg. Recoveries of the spiked samples were mostly in the range of 80-120%. The LOD of the ELISA was found below 1 mg/kg. The analysis of 39 different substances of interest revealed that no cross-reactivity above the LOQ occurred. Ruggedness testing proved that variations in incubation temperature, reagent volume, incubation time, extraction temperature, and extraction time had no significant influence. The stability at 4-8°C of three independent lots was investigated and found to exceed 18 months. Very good lot-to-lot consistency and no significant loss of the analytical capacity over the shelf life were observed. Incurred cookies and chocolate dessert samples were prepared and analyzed by an independent laboratory; mean recoveries of 94.4 and 102.2% and mean SDs of 10.9 and 6.3%, respectively, were found. For the 0 mg/kg level for both materials, all samples tested returned values of