Effect of interaction with food constituents on plant extracts antibacterial activity

Abstract

Gaillac red wine powder and Cinnamon cassia essential oil were selected for their in vitro antibacterial activity against Staphylococcus aureus CNRZ3 and Listeria innocua LRGIA 01, respectively. In order to assess the potential application of Gaillac wine powder to the preservation of raw meat, its antibacterial activity was assayed in Mueller Hinton broth supplemented with up to 20% (w/w) bovine meat proteins (bovine meat protein content): Gaillac wine powder as well as resveratrol, a stilbene polyphenol present in red wine, lost their antibacterial activity, likely as a result of interactions of Gaillac wine antibacterial molecules with bovine meat proteins at the expense of their interactions with S. aureus CNRZ3 cells. Cinnamon cassia essential oil antibacterial activity assays in Tryptone Soya broth, skimmed, semi-skimmed, and whole milk showed that its antibacterial activity was significantly reduced by milk fat globules but not by milk proteins: it could thus be used for the preservation of skimmed milk. The developed methodology based on the use of microbiological media mimicking the composition of perishable foods or of liquid foods such as sterilized milk with various milk fat contents could be used for the rapid screening of antibacterial plant extracts of interest for perishable foods preservation.