A method and composition for extracting an analyte from a test sample such as grain, so as to determine whether the test sample is contaminated with a toxin. The method is particularly useful for detecting the presence in a batch of grain of a mycotoxin, such as for example aflatoxin, ochratoxin, T2, zearalanone, vomitoxin (deoxynivalenol a/k/a DON), patulin and fumonisin. Extraction is performed with use of a composition that includes a proteinaceous material, such as albumin, as an extraction agent.