Resistance evaluation biological controller yeast to substances "GRAS" - (Generally Regarded As Safe) / Avaliação da resistência de leveduras biocontroladoras à substâncias “GRAS” - (Generally Regarded As Safe)

Abstract

Biological control has been integrated into substances known as "GRAS" (Generally Regarded As Safe), these substances are commonly used as food additives, and its main role is to assist the biological agents antagonistic action. This study aimed to test the effects of five "GRAS substances " over the growth of four strains of yeast (5822, 5852, 5859, 5872) selected by presenting characteristics of good biocontrol agents. To perform the test, the strains were grown in GYMP broth with the addition of substances sodium bicarbonate, sodium carbonate, calcium carbonate, calcium chloride and potassium chloride at concentrations of 1%, 3% and 5% with the exception of chloride whose potassium concentrations were 0.1%, 0.5% and 1% (maximum concentration permitted by law). On days 1, 4, 7, and 10 after incubation an aliquot of 50 µl was removed and plated cultures, and the results expressed as CFU / ml. Among the four tested strains, only 5852 was able to survive seven days in the presence of sodium bicarbonate at the three concentrations tested. Demonstrating the ability of this yeast to be used in integrated biological control protocols with this substance.