Antibacterial Activity Of Essential Oil Of Syzygium cumini Leaf Against Pathogenic And Spoilage Bacteria Isolated From Cheese

Abstract

local cheese has been reported to be a high risk food in Nigeria due to the possible transmission of numerous spoilage and pathogenic bacteria. This study therefore investigated not only the spoilage and pathogenic bacteria associated with local cheese sold within Ilorin metropolis but also microbiological food safety of the food through the use of Syzygium cumini oil as a preservative. Samples of wara were collected from selected seller across the metropolis and analysed for the presence of different bacterial species using spread plate method on appropriate selective growth media. All the bacterial isolates were identified using biochemical test. Invitro therapeutic efficacy of S.cumini oil aginst foodborne isolates was carried out using Kirby-Bauer method. The most six prevalent bacterial isolates were Bacillus subtilis, Proteus vulgaris, Escherichia coli, Listeria monocytogene, Salmonella typhimurium and Staphylococcus aureus were isolated from the wara. Hydrodistilled leaves of Syzygium cumini yielded 0.32% (v/w) of essential oil. Examination of the oil by GC and GC/MS uncovered that the greater part of the oil was comprised by sesquiterpenes. Other outstanding constituents were Cis-Beta-Farnesene (1.40%), Beta-Ocimene (2.11%), Beta-bisabolol (1.48%), Beta-Ocimene (2.11%), and D-Limonene (2.89%). Antibacterial action was measured base on the zone of inhibition and minimum inhibitory concentration. The oil repressed the development of Proteus vulgaris at 25% concentration, Escherichia coli at 12.5% concentration, Listeria monocytogene at 6.25% concentration, Salmonella typhimurium at 12.5% concentration and Staphylococcus aureusat 6.25% concentration while no action was recorded against B. subtilis. Highest activity, represented by diameter of zone of clearance around the loaded wells was recorded for Staphylococcus aureus. Accordingly, the oil can be an elective method for averting spoilage in stored wara in this manner expanding its time span of edibility.