Phenolic extracts from grape stems inhibit Listeria monocytogenes motility and adhesion to food contact surfaces

This study evaluated the effect of grape stems extracts on motility, surface energy and adhesion of L. monocytogenes to stainless steel and polypropylene surfaces. Stem extracts from Red Globe grapes showed a higher content of total phenolics than Carignan stems. Moreover, both extracts reduced adhesion of Listeria to stainless steel (0.77-2.22 log CFU cm-2) and polypropylene (0.71-2.38 log CFU cm-2) and completely inhibited bacterial motility at 4.5 and 5 mg mL-1 of Red Globe and Carignan extracts, respectively. Similarly, both extracts affected the surface energy of bacteria and modified the adhesion potential of L. monocytogenes to both surfaces. Otherwise, caffeic, ferulic and gallic acids, catechin and rutin, presented in both extracts, reduced adhesion of L. monocytogenes to stainless steel (0.39-2.04 log CFU cm-2) at 10 mM. In conclusion, Red Globe and Carignan grape stem extracts inhibited adhesion of L. monocytogenes to stainless steel and polypropylene surfaces by inhibiting motility and modifying its adhesion potential.