Label-free immuno-sensors for the fast detection of Listeria in food

Listeria monocytogenes is one of the major foodborne pathogen found in a large set of foodstuff. With the aim of decreasing listeriosis occurrence, the early detection of this pathogen in food products is of tremendous interest. So far, the reference method and all the alternative methods require a pre-enrichment step lasting 24 h to several days. Then, an aliquot of the enriched sample is collected and characterized according different methods including genetic analysis, or beads immuno-agglutination. With the aim of significantly decreasing the overall processing time, we propose an approach involving the detection of alive bacteria during their growing phase via the use of an immuno-chip SPR imaging process. Listeria specific antibodies were also produced and chemically grafted on the biochip before being selected for their ability to distinguish different Listeria strains. Finally, this approach allows the detection of a very low number of L. monocytogenes present in foodstuff.