Antibacterial activity of smoke wood condensates against Aeromonas hydrophila, Yersinia enterocolitica andListeria monocytogenes at low temperature Original Research Article

The antibacterial activity of four commercial preparations of smoke condensates was tested against three psychrotrophic foodborne pathogens (Aeromonas hydrophila, Yersinia enterocolitica and Listeria monocytogenes). The effects of the recommended concentrations for the use of one dried (S) and three liquid (L1, L2, L3) extracts were examined in tryptic soy broth for 21 days at refrigeration temperature. The results revealed that smoke extracts differed considerably in their ability to inhibit the growth of the investigated pathogens. A. hydrophila was the most susceptible organism. Extracts L1, L2 and S caused a gradual decline in A. hydrophila viable cell counts to reach undetectable levels. Extracts S was bacteriostatic to L. monocytogenes and Y. enterocolitica. Extract L1 reduced populations of these organisms during the experiment. Extract L2 reduced the population of L. monocytogenes. This extract did not affect, however, Y. enterocolitica growth. The least effective extract was L3 which only inhibited the growth of A. hydrophila during the experimental period and did not show any effect against L. monocytogenes and Y. enterocolitica. The compounds and their relative concentrations identified and quantified by gas chromatography/mass spectrometry varied greatly among the analysed condensates. No relation has been shown between the antimicrobial activity and the concentration of phenols of smoke preparations.