To confirm the presence of inserts, 140 white colonies were picked from the organic salad sample, as well as M. Handschur et al. / Food and Chemical Toxicology 43 (2005) 1595–1605 1597 from packed salad sample respectively. The picked colonies were resuspended in 40 ml TE buffer [10 mM Tris,1 mM EDTA, pH = 8].