RAPID ISOLATION AND DETECTION OF <i>ESCHERICHIA COLI</i> O157:H7 IN FRESH PRODUCE

Abstract

ABSTRACT This study describes a rapid method for the isolation and detection of Escherichia coli O157:H7 present at low levels (0.04–0.4 cfu/g) in fresh salad produce. Following a short enrichment (5 h at 42C), samples were processed using Pathatrix, a novel recirculating immunomagnetic capture system, linked to real‐time polymerase chain reaction and/or selective agar plating. Processing of post‐enrichment sample aliquots (10 mL diluted 1:25) and the use of preblocked paramagnetic anti‐ E. coli O157:H7 beads enhanced target pathogen recovery on selective agar plates in cases where a high microbial load of nontarget microflora was present. This is of particular relevance to the testing of bean sprouts. This method has the potential to provide a result within 7 h. The speed of result offers significant benefits for outbreak investigations and allows the rapid screening of salad produce for E. coli O157:H7 contamination prior to product entering the distribution chain.