An in vitro cultivation model for Salmonella having contact to epithel
ial cells was developed, which led to an increase in the production of
toxic substances. The toxin assay on CHO-K1 cells was used for the de
termination of the toxic activities. Salmonella strains cultivated in
contact with a monolayer of the intestinal cell line IEC-6 produced co
nsiderably more toxin than Salmonella strains cultivated on VERO cells
. The toxin formed was heat-labile.