Disclosed are methods and apparatus obtaining in-situ, real-time data associated with a sample stream obtained by a downhole sampling apparatus disposed in a borehole that extends into a subterranean formation. The obtained data includes multiple fluid properties of the sample stream. The sample stream includes native formation fluid from the subterranean formation and filtrate contamination resulting from formation of the borehole in the subterranean formation. The obtained data is filtered to remove outliers. The filtered data is fit to each of a plurality of models each characterizing a corresponding one of the fluid properties as a function of a pumpout volume or time of the sample stream. Based on the fitted data, a start of a developed flow regime of the native formation fluid within the subterranean formation surrounding the borehole is identified.