Natural antimicrobials are being more and more considered as alternative approach for controlling
growth of microorganisms in food. The objective of this study was to evaluate the pomegranate extract’s
(PE) potential to be used as a natural preservative in ready to eat meats. Listeria monocytogenes was the
main target. In a preliminary assessment with the disk diffusion method PE showed inhibitory effect
against all five tested species, in the following order of increasing sensitivity: L. monocytogenes, Bacillus
subtilis, Bacillus cereus, Escherichia coli and Staphylococcus aureus.
No viable cells of L. monocytogenes were detected after incubation in BHI broth in presence of 7.5% v/v
of the liquid PE (or 24.7 mg dry PE/ml). This concentration was considered as the Minimal Bactericidal
Concentration (MBC) of the tested PE. Two pure components commonly found in PE, namely gallic and
ellagic acids were also tested in BHI broth, however they did not show considerable inhibition of
L. monocytogenes. PE in a concentration equal to the measured MBC was tested against L. monocytogenes
in meat paté at different temperatures. At 4 C during 46 days the extract inhibited the growth in meat
paté by 4.1 log CFU/g compared to the control, which had reached log 9.2 CFU/g already on the 18th day.
Inhibition was less pronounced at higher temperatures. The results indicate that the PE has a potential to
be used as a natural preservative in meat products.