EFFECT OF OLEUROPEIN AND SODIUM-CHLORIDE ON VIABILITY AND METABOLISM OF LACTOBACILLUS-PLANTARUM

The effect of the addition of oleuropein (OLP) and NaCl on the growth and the Dr-lactic acid production of Lactobacillus plantarum DSM 10492 has been investigated by using an unconventional medium. The growth o f L. plantarum was not inhibited by the addition of increasing amounts of untreated OLP in the presence or absence of glucose. However, bact erial cells grew in quantity slightly with OLP alone. The increased ad dition of NaCl was associated with a delay in growth. Moreover, there was no growth with 8% NaCl. The addition of both NaCl and OLP resulted in growth inhibition, and the survival of cells decreased strongly. T he main fermentation product was DL-lactic acid, but acetic acid was a lso detected after a prolonged incubation. L. plantarum produced DL-la ctic acid in the presence of OLP alone but its formation decreased wit h increasing levels of OLP. On the other hand, heat-treated OLP had a bactericidal effect.