Investigation of the influence of plant tissue damage on the attachment of Listeria to fresh salad produce

Abstract

Vegetables and fruits are an important for a healthy life due to them containing nutritionally important minerals and vitamins. Green salads (spinach, lettuce) are popular convenience consumer products, however evidence is increasing that these ready to eat salads have been identified as a source of foodborne illness. There are many pathogenic bacteria which are transmitted by food that can cause serious disease. One of the most important is Listeria monocytogenesbecause it can cause invasive infections and especially because of its ability to grow at low (food refrigeration) temperatures. The aim of this study is to investigate whether compounds released from damaged fresh salad leave have an effect on Listeria growth and virulence. The results in this report show that Listeria was highly responsive to the salad extracts and that growth and biofilm formation were both increased compared to un-supplemented control cultures. Plant derived chemicals also stimulated Listeria growth in serum-SAPI medium. The results also showed that Listeria treated with salad extract was more virulent in a Galleria mellonella infection model.