The antimicrobial activity of carvacrol, a compound present in the essentia
l oil fraction of oreganum and thyme, toward the foodborne pathogen Bacillu
s cereus on rice was studied. Carvacrol showed a dose-related inhibition of
growth of the pathogen. Concentrations of 0.15 mg/g and higher inhibited t
he growth and the extent of inhibition depended on the initial inoculum siz
e. To decrease the input of carvacrol on the taste and flavor of the produc
t, a combined treatment with the structure analog cymene was tested. Due to
the smell and taste of carvacrol at high concentrations, carvacrol was com
bined with cymene, a natural antimicrobial compound with a similar structur
e. A synergistic effect was observed when 0.30 mg/g carvacrol was combined
with 0.27 mg/g cymene. Finally it was demonstrated that a common taste enha
ncer like soya sauce also increased the antimicrobial action of carvacrol t
oward B. cereus. The antimicrobial activity of carvacrol with cymene or soy
a sauce was influenced by the addition of NaCl.