Ecophysiological attributes of Salmonella typhimurium in liquid culture and within a gelatin gel with or without the addition of oregano essential oil

The growth of Salmonella typhimurium in liquid culture and in a gel matrix system at two pH values (5.0 and 7.0) with (0.03% w/v) or without oregano e ssential oil was studied. It was shown that the type of growth media (liqui d or gel) influenced significantly both the type of end-product formation a nd growth of bacteria as well as the inhibitory efficacy of the essential o il. The oil inhibited S. typhimurium more strongly in the liquid medium tha n in the gelatin matrix. In particular, the addition of essential oil in ge latin matrix delayed the initiation of growth and caused a slight suppressi on of the maximum population level, while in liquid culture, growth was pre vented completely in identical conditions. Structure also was found to affe ct the rate of consumption of glucose and the rate of production of end pro ducts. Formic and acetic acids were produced in both systems, while an unid entified peak was formed only in broth samples.