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Inhibitory Effect of Eleutherine americana Merr. Extract on Staphylococcus aureus Isolated from Food
Author(s) -
Ifesan B.O.T.,
Hamtasin C.,
Mahabusarakam W.,
Voravuthikunchai S.P.
Publication year - 2009
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2008.01004.x
Subject(s) - staphylococcus aureus , biology , food science , inhibitory postsynaptic potential , traditional medicine , medicine , bacteria , endocrinology , genetics
About 106 samples of ready‐to‐eat foods were purchased over a period of 3 mo out of which 76 (71.69%) were contaminated with Staphylococcus aureus . S. aureus isolated from the food samples were characterized phenotypically using traditional biochemical methods. Ninety‐four percent of the isolates were mannitol fermenters, 86% positive for coagulase test, while 80% produced lipase enzyme. Antibiotic susceptibility test revealed that 21% and 63% of the food isolates were resistant to oxacillin and penicillin, respectively. The antibacterial activity of the bulb of Eleutherine americana used in Thai cuisine was investigated by agar disc diffusion using 2.5 mg of the crude extract and produced inhibition zone between 14.5 and 15.7 mm, while the minimum inhibitory concentration (MIC) value ranged from 0.06 to 1.00 mg/mL on both food isolates and reference strains. Growth curve in the presence of the crude ethanol extract at 4 MIC showed bacteriostatic effect by 5 log reduction relative to the control. Partially purified fractions tentatively identified by column chromatography were suspected to be responsible for the antibacterial property. This study suggests that E. americana bulb has potential for application as a natural preservative in foods.