Antibacterial activity of Citrus paradisi essential oil

Abstract

The aim of this work was to determine the effectiveness of Grapefruit (Citrus paradisi) essential oil to inhibit the growth of wild food-borne spoilage and pathogenic bacterial strains. Additionally, the chemical composition and physical properties of this essential oil was evaluated. Essential oil was obtained as a byproduct from agro-processing industry in the province of Corrientes, Argentina. Monoterpene hydrocarbon limonene representing 93% (v/v), quantified by gas chromatography, was the major component of essential oil. Citrus paradisi essential oil inhibited growth of Escherichia coli, Staphylococcus aureus, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. diacetylactis, Leuconostoc mesenteroides subsp. dextranicum and Lactobacillus plantarum. The lowest concentration of essential oil (4.29ppm) was required to inhibit Lactococcus lactis subsp. lactis 207c VCOR (8.27±0.13 log10 CFU/ml) according to the Minimum Inhibitory Concentration. The effect of this oil on growth of wild strain 207c VCOR (9.17±0.024 log10 CFU/ml) was determined at different times by total count and spectrophotometric absorption to 560 nm. At the moment of essential oil injection, the number of microorganisms was 1.29±0.17x109 CFU/ml and, at 24 hours of contact, only 6.3±0.5x106 CFU/ml was detected. These results show that oil has a bactericidal effect if counts with and without addition of essential oil were compared. The loss of viability was 1.82x109 CFU/ml under these experimental conditions. This essential oil has very strong potential applicability as a natural antibacterial agent for food industry, particularly for pasta manufacture which is facing serious spoilage problems due to lactic bacteria activity.