The effect of the stirring rate on the crystallization of sodium chlorate was studied in more than 200 experiments using a set-up that allows to perform sets of 20 simultaneous experiments. The crystallization conditions were those that according to previous results lead to only one of both L and D enantiomorphic forms under stirring. The probability of D crystallization was determined using a statistical analysis based on the central limit theorem. The stirring dependence of induction times and crystal size distribution is reported. The stirring effect was correlated with differences between surface and bulk crystallization. The probability of D crystallization was detected to be slightly higher than that of the L, in contradiction with some previous reports, and that might be attributed to the chiral contamination of the bio-organic world on the starting materials and on the system. Our analysis allows to detect that the D-enantiomorph induction by chiral contamination occurs mainly in the nucleation at the interface air/water, which can be related to the expected higher concentration of the contaminants (bioorganic chiral amphiphiles e.g. DNA or proteins) on the surface of the solution. (C) 2007 Elsevier B.V. All rights reserved.