Role of erythrosine in the inhibition of adhesion of Lactobacillus fermentum strain 737 to mouse stomach tissue.

The mechanism by which the food colour erythrosine inhibits the adhesion of Lactobacillus sp. to squamous epithelium in the mouse stomach was investigated using an in vitro adhesion assay. Inhibition of adhesion occurred only after growth of L. fermentum in erythrosine which bound to the bacterial cell surface. Erythrosine did not interfere with the receptor on the epithelial cell surface. Growth, but not the ATP content per cell, was affected by the presence of erythrosine in the growth medium. No consistent correlation between hydrophobicity and growth in two different broths was noted when erythrosine was present. Analyses of phenol/water extracts and transmission electron micrographs revealed no reduction in extracellular polysaccharide after growth in the presence of erythrosine. It was concluded that erythrosine affects bacterial metabolism thereby preventing production of the bacterial adhesin which is not the extracellular polysaccharide.