Industrial Crops and Products 42 (2013) 243–250 Contents lists available at SciVerse ScienceDirect Industrial Crops and Products journa l h o me page: www.elsevier.com/locate/indcrop Antimicrobial activity of lavandin essential oil formulations against three pathogenic food-borne bacteria Salima Varona a,∗ , Soraya Rodríguez Rojo a , Ángel Martín a , María José Cocero a , Ana Teresa Serra b , Teresa Crespo b,c , Catarina M.M. Duarte b,c a High Pressure Processes Group, Department Chemical Engineering and Environmental Technology, University of Valladolid, Spain b Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal c Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal a r t i c l e i n f o Article history: Received 6 September 2011 Received in revised form 3 April 2012 Accepted 19 May 2012 Keywords: Lavandin essential oil Antimicrobial Biocide Foodborne pathogens PGSS PGSS-drying Spray-drying a b s t r a c t Lavandin (Lavandula hybrida) essential oil contains components with biocide and antiviral properties that can be used as substitutes of antibiotics. This application requires an appropriate formulation of the essential oil. In the present work, the antimicrobial activity of free and encapsulated lavandin essential oil against three pathogenic bacteria (Gram-negative: Escherichia coli; Gram-positive: Staphylococcus aureus and Bacillus cereus) was determined. The formulations were prepared using innovative high-pressure techniques (PGSS and PGSS-drying) as well as spray-drying. Carrier materials used for the encapsulation were soybean lecithin, n-octenyl succinic anhydride (OSA) modified starch and poly-caprolactone. Results demonstrated that lavandin oil antibacterial activity could be enhanced by encapsulation, due to the protection and control release of the oil. As well, encapsulation might present an interesting opportunity to facilitate the action of antimicrobials, improving essential oil penetration inside of the outer membrane. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Public concern about the use of antibiotics in livestock feed has increased, because the emergence of antibiotic resistant bac- teria and their possible transmission from livestock to humans. In fact, in the European Union the use of synthetic antibiotics, health and growth promoters as additives in livestock feed is prohibited since 2006 (European Parliament and Council Regulation (EC) No. 1831/2006). In this context, one possible solution is the used of essential oils. Essential oils are recognized as safe substances (ESO, GRAS – 182.20) by the Food and Drug Administration (2005) and some contain compounds which can be used as antibacterial addi- tives (Ait-Ouazzou et al., 2011; Cox et al., 2001; Nerio et al., 2010; Miˇ si´ c et al., 2008; Muyima et al., 2002). However, the required concentration of the essential oils for an effective biocide action can be about 100 times higher than that of a standard antibiotic (e.g. streptomycin and nystatin) (Hanamanthagouda et al., 2010). Thus, essential oils must be adequately formulated to protect them from degradation, evaporation and to provide a controlled release. The encapsulation has demonstrated to improve the antibacterial ∗ Corresponding author. E-mail address: salimavarona@gmail.com (S. Varona). activity of several antibiotics (Drulis-Kawa and Dorotkiewicz-Jach, 2010). The formulations tested in this work are based on lavandin essential oil and were prepared using three types of carriers, namely: lecithin, OSA modified starch and polycaprolactone, using three different encapsulation processes: PGSS (particles from gas saturated solutions), PGSS-drying (PGSS-D) and spray-drying (SD). The preparation of these formulations is reported in Varona et al. (2009, 2010, 2011). Spray-drying is one of the best-known conventional technolo- gies for the precipitation and co-precipitation of particles for food and pharmaceutical application, but its main drawback is the high temperature needed. PGSS and PGSS-drying are new technologies which use compressed carbon dioxide as solvent. This solvent is non toxic, environmentally friendly and can be eliminated completely from the final product by depressurization. PGSS and PGSS-drying processes allow to work mild conditions and therefore to reduce lavandin oil degradation. The PGSS process takes advantage to the fact that polymers can be saturated with carbon dioxide decreasing their melting temperature (De Paz et al., 2010). The present study takes into consideration the possible use of lavandin essential oil (Lavandula hybrida) as a natural bio- cide by means of a suitable formulation. With this aim, several lavandin oil formulations has been produced and tested against 0926-6690/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.indcrop.2012.05.020