Place slide on staining rack and flood with methanol. Let stand 30 s, pour off methanol, and allow slide to air-dry. Heat slide gently from below with small Bunsen burner until steam is seen. Wait 1-2 min and repeat this step. Let stand 30 s, pour off stain, and rinse slide thoroughly with clean tap water.
Crystals are usually somewhat smaller than spores.
Therefore, unless free spores can be seen, cultures should be held at room temperature for a few more days and re-examined for toxin crystals. Interpreting test results . On the basis of the test results, identify as B . cereus those isolates which are actively motile and strongly hemolytic and do not produce rhizoid colonies or protein toxin crystals. Nonmotile B . These nonpathogenic strains of B .