RETRACTED: A medium for the presumptive detection of Enterobacter sakazakii in infant formula (Retracted Article. See vol 23, pg 409, 2006)

A differential-elective medium for the isolation of Enterobacter sakazakii was developed. It is based on the presence of an enzyme alpha-glucosidase in this species that can differentiate this organism from other members of the family Enterobacteriaceae. Nutrient agar (NA) was supplemented with 4-methyl-umbelliferyl alpha-D-glucoside (alpha-MUG). This Substrate was metabolized by the enzyme to yield an UV fluorescent product. E sakakakii formed yellow pigmented UV fluorescent colonies on NA with alpha-MUG. Fifty-six E. sakazakii strains from culture collections were examined and found positive for both characteristics. Fifty-eight formula products from 11 countries were sampled in their entity by using a pre- and selective enrichment method following ISO 8523. The selective enrichment was streaked on NA + alpha-MUG and violet red brilliant green (VRBG) agar. Twenty-one (36%) of products were positive for Enterobacteriaceae. E. sakazakii was isolated from eight out of 58 infant formula products representing 13.8%. (C) 2003 Elsevier Ltd. All rights reserved.