Application of the Stomacher for rapid homogenization of sputum and the serial streak dilution method for quantitative culture.

Techniques for sputum homogenization and quantitative cultural methods have enabled clinical microbiologists to make a more objective assessment of the bacterial flora found in lower respiratory tract infection. This paper describes the application of the Colworth Stomacher for rapid and effective homogenization of sputum and the use of a calibrated loop for quantitative culture of the homogenate. The Stomacher (A. J. Seward, London SEI 9U6) has been designed for the blending of powders, liquids, samples for microbiological analysis, emulsification, and extraction. A suitable plastic bag containing the sample is placed in the stomaching area and sealed near the top by the closed Stomacher door. Two paddles alternately squeeze the bag and its contents against the inner aspect of the door (Sharpe and Jackson, 1972).