Effect of Essential Oils on Germination and Growth of Some Pathogenic and Spoilage Spore-Forming Bacteria

Abstract

The use of essential oils as a food preservative has increased due to their capacity to inhibit vegetative growth of some bacteria. However, only limited data are available on their effect on bacterial spores. The aim of the present study was to evaluate the effect of some essential oils on the growth and germination of three Bacillus species and Geobacillus stearothermophilus. Essential oils were chemically analyzed using gas chromatography and gas chromatography coupled to mass spectrometry. The minimal inhibitory and bactericidal concentrations of vegetative growth and spore germination were assessed using the macrodilution method. Germination inhibitory effect of treated spores with essential oils was evaluated on solid medium, while kinetic growth was followed using spectrophotometry in the presence of essential oils. Essential oil from Drypetes gossweileri mainly composed of benzyl isothiocyanate (86.7%) was the most potent, with minimal inhibitory concentrations ranging from 0.0048 to 0.0097 mg/mL on vegetative cells and 0.001 to 0.002 mg/mL on spore germination. Furthermore, essential oil from D. gossweileri reduced 50% of spore germination after treatment at 1.25 mg/mL, and its combination with other oils improved both bacteriostatic and bactericidal activities with additive or synergistic effects. Concerning the other essential oils, the minimal inhibitory concentration ranged from 5 to 0.63 mg/mL on vegetative growth and from 0.75 to 0.09 mg/mL on the germination of spores. Spectrophotometric evaluation showed an inhibitory effect of essential oils on both germination and outgrowth. From these results, it is concluded that some of the essential oils tested might be a valuable tool for bacteriological control in food industries. Therefore, further research regarding their use as food preservatives should be carried out.

Inhibition of bacterial human pathogens on tomato skin surfaces using eugenol‐loaded surfactant micelles during refrigerated and abuse storage

“…Plant-derived essential oil components (EOCs) are composed of heterogeneous mixtures of organic compounds, some volatile, that may be obtained from parts of plant tissues (e.g., buds, flowers, seed, leaves, twigs, fruits, bark, woods, and roots) by steam distillation and/or solvent extraction (Burt, 2004;Seow, Yeo, Chung, & Yuk, 2014). EOCs have been widely studied for their capabilities to inhibit the growth, or reduce numbers, of foodborne bacterial microbes in liquid and on solid foods (Lawrence & Palombo, 2009;Nazzaro, Fratianni, De Martino, Coppola, & De Feo, 2013;Nuñez & Aquino, 2012;Park, Kang, & Song, 2018;Smith-Palmer, Stewart, & Fyfe, 1998;Voundi et al, 2015). EOCs containing phenolic groups in particular are reported to exhibit antimicrobial activity against several bacterial foodborne pathogens (Rota, Carraminana, Burillo, & Herrera, 2004;Seow et al, 2014).…”

Inhibitory Effect of Spice Powders on the Development of Heated and Irradiated <i>Bacillus subtilis</i> Spores as Evaluated by Calorimetry

“…On bacterial cells, these essential oils damage cell membranes and perturb metabolic activities in bacteria. Also for spores, Voundi et al 2015 reported that essential oils of thyme suppressed the germination of spores from Bacillus cereus, B. subtilis and Bacillus megaterium.…”

Optimized Culture Conditions for the Detection of Selected Strains of Bacillus in Eye Creams

“…In this study, essential oils contained in Product C inhibited the cells, and the cells were practically not detected after 24 h pre-enrichment at 30 • C and remained under the detection limit (0.04 log MPN/g). Voundi et al [23] demonstrated that some essential oils had a bactericidal effect on vegetative cells and an inhibitory effect on both the germination and the outgrowth of Bacillus spores. Essential oils could damage a variety of targets within bacterial cells, particularly the membrane and cytoplasm, and in certain situations the action of these oils can completely alter the morphology of the cells [24].…”