Treatment of vegetable sauces with enterocin AS-48 alone or in combination with phenolic compounds to inhibit proliferation of Staphylococcus aureus

The antimicrobial activity of enterocin AS-48 against Staphylococcus aureus was tested in vegetable sauces, alone and in combination with phenolic compounds. When added alone at 25 microg/ml, AS-48 inactivated all detectable staphylococci in napoletana and pesto sauces stored at 22 degrees C, but it only caused limited growth inhibition when these sauces were stored at 10 degrees C, as well as in other sauces such as carbonara and green sauce for fish. At 80 microg/ml, AS-48 eliminated all detectable staphylococci in napoletana, pesto, and green sauce for fish regardless of storage temperature, but it still had much more limited effect in carbonara sauce. Antistaphylococcal activity was potentiated significantly when AS-48 was used in combination with the phenolic compounds carvacrol, geraniol, eugenol, terpineol, caffeic acid, p-coumaric acid, citral, and hydrocinnamic acid. The efficacy of the combined treatments depended both on the phenolic compound and the type of sauce. In carbonara sauce stored at 22 degrees C, the combinations of 80 microg/ml AS-48 and 20 mM hydrocinnamic acid or 126 mM carvacrol reduced viable counts of staphylococci below detection limits for up to 30 days.