Antimicrobial Activity of Some Plant Essential Oils Against Listeria monocytogenes

Abstract

The antimicrobial activity of 32 plant essential oils commonly used in food industry was examined against four strains of Listeria monocytogenes and one strain of Listeria innocua. Two different procedures were carried out to test the essential oils, a paper disc diffusion method and an inhibition curve. In the former procedure an absolute ethanolic solution (1:5 v/v) of each oil was tested on the plates inoculated with a bacterial concentration of 106 CFU/ml. Five of the 32 essential oils (cinnamon, clove, origanum, pimento, and thyme) showed antibacterial activity. Some of the five oils were also tested at lower concentration (1:50 v/v). The inhibition curve to study antilisteric efficacies of the five oils in a saline solution system was examined. Pimento oil showed marked and rapid activity (generally within 1 h of exposure), whereas clove, origanum, and thyme oils showed a more slow activity. The antilisteric activity of the tested oils seems to be strain dependent. A L. monocytogenes strain was also tested in a food matrix (minced pork meat) against thyme essential oil. Minced pork meat with thyme oil reduced the L. monocytogenes population by ca. 100-fold over the first week of storage.

Concise and informative title: evaluation of selected spices in extending shelf life of paneer

“…In addition to imparting flavour, certain spices prolong the shelf life of foods due to their bacteriostatic or bacteriocidal activity, and some prevent rancidity by their antioxidant activity (Shelef 1984). Many plant essential oils of spices are active against various food borne bacteria and moulds (Aureli et al 1992). Selected spices have been reported to have antimicrobial properties.…”

Evaluation of efficacy of turmeric as a preservative in paneer

“…Inhibitory activity of herbs and derivatives on the growth of bacteria, fungi and microbial toxins has been well reported (Zaika 1988). Many plant essential oils of herbs are active against various food borne bacteria and molds (Aureli et al 1992). Herbs and spices have also been well known for their medicinal, preservative and antioxidant properties (Souza et al 2005) hence they could be used for food preservation as main or adjuvant antimicrobial substances.…”

Effect of ethanolic extract of clove on the keeping quality of fresh mutton during storage at ambient temperature (25 ± 2 °C)

“…Reports on the use of spices or herbs as preservatives can be traced to 1550 BC, when the ancient Egyptians used certain spices for food preservation. Spices like clove and cinnamon generally used in Indian culinary have been reported to exhibit suppressing action on many food borne pathogens (Bahk et al 1990;Aureli et al 1992;Jeyashakila et al 1996;Lis-Balchin and Deans 1997;Smith-Palmer et al 1998;Moreira et al 2005;Mytle et al 2006). The antimicrobial activity of clove has been extensively reviewed (Subbulakshmi and Naik 2002).…”