Cymbopogon citratus Essential Oil: Its Application as an Antimicrobial Agent in Food Preservation

Abstract

Antimicrobial in vitro and in situ efficacies of Cymbopogon citratus essential oil (lemongrass, LGEO) against 17 spoilage microorganisms (bacteria, yeasts and fungi) were evaluated. Additionally, its chemical composition, and antioxidant and antibiofilm activities were investigated. The LGEO exhibited a strong antioxidant activity (84.0 ± 0.1%), and its main constituents were citral (61.5%), geraniol (6.6%) and 1,8-cineole (6.4%). An in vitro antimicrobial evaluation revealed the lowest inhibition zone (1.00 ± 0.00 mm) in Pseudomonas fluorescens, and the highest inhibition zone (18.00 ± 2.46 mm) in Candida krusei. The values for the minimal inhibitory concentration were determined to be the lowest for Salmonella enteritidis and the highest for C. albicans. Furthermore, the concentration of ≥250 µL/L of LGEO suppressed the growth of Penicillium aurantiogriseum, Penicillium expansum, Penicillium chrysogenum and Penicillium italicum. The changes in the molecular structure of the biofilms produced by Pseudomonas fluorescens and Salmonella enteritidis, after their treatment with LGEO, confirmed its action on both biofilm-forming bacteria. Moreover, an in situ antimicrobial activity evaluation displayed the most effective inhibitory effectiveness of LGEO against Micrococcus luteus, Serratia marcescens (250 µL/L) and Penicillium expansum (125, 250 and 500 µL/L) growing on a carrot. Our results suggest that LGEO, as a promising natural antimicrobial agent, can be applied in the innovative packaging of bakery products and different types of vegetables, which combines commonly used packing materials with the addition of LGEO.

Assessment of Chemical Composition and Anti-Penicillium Activity of Vapours of Essential Oils from Abies Alba and Two Melaleuca Species in Food Model Systems

“…These EOs were obtained by a commercial producer Hanus Ltd. (Nitra, Slovakia), and were preserved at 4 °C in the laboratory refrigerator until their next use. Importantly, the research complements our knowledge gained in previous similar experiments [ 33 , 71 ]. In this regard, it provides a comprehensive overview of the biological effects of different types of commercial EOs obtained from the same company.…”

“…Many studies indicated antifungal efficacy of different EOs types against a wide range of fungal strains such as Penicillium spp. ( P. polonicum , P. expansum , P. citrinum , P. crustosum , P. funiculosum , P. brevicompactum , P. glabrum , P. oxalicum , P. chrysogenum ) [ 32 , 33 ]. Very strong antifungal action of the highest REO concentration against P. citrinum growth observed in our study is reinforced by the work of Farag et al [ 18 ], whose REO (in the concentration of 5 µL on the filter paper discs) exhibited the highest inhibitory effects (inhibition zone 18.3 mm) on the growth of Aspergillus (A.)…”

“…The volatile compounds of the EOs were determined using gas chromatography with mass spectrometry (GC-MS), as it was described by Valková et al [ 33 ]. In brief, the analysis was carried out by Agilent Technology 6890N (Agilent Technologies, Santa Clara, CA, USA) coupled to quadrupole mass spectrometer 5975B (Agilent Technologies, Santa Clara, CA, USA).…”

“…After the separation, the components were identified based on the comparison of their relative retention index and compared with the library mass spectral database (Wiley and NIST databases). The percentage composition of compounds (relative quantity; amounts higher than 0.1%) was measured based on the peak area [ 33 ]. The retention indices were experimentally determined by injecton of standard n-alkanes (C 6 –C 34 ) under the same chromatographic conditions.…”

“…Evaluation of the in vitro antifungal activity of the EOs was performed using the agar disc diffusion method, according to Valková et al [ 33 ] with minor modifications. For this purpose, an aliquot of 100 µL of culture media was inoculated on SDA.…”