The present invention provides a method and system for monitoring, detecting, and/or characterizing a biological particle that may be present in a sample. The method may be accomplished in a sealed container by utilizing a first step time-dependent spectroscopic technique to obtain at least two measurements of a growth composition comprising a sample and correlating said measurements for the detection and/or characterization of a biological particle that may be present in the sample. The method further provides for a subsequent step for the separation, characterizion and/or identification of the microorganisms in the sealed container.