0139–3006/$ 20.00 © 2017 Akadémiai Kiadó, Budapest Acta Alimentaria, Vol. 46 (1), pp. 92–99 (2017) DOI: 10.1556/066.2017.46.1.12 ENHANCEMENT OF BACTERIOCIN PRODUCTION AND ANTIMICROBIAL ACTIVITY OF PEDIOCOCCUS ACIDILACTICI HA-6111-2 J.M. GARCIA a , S.M. CASTRO a,b , R. CASQUETE a,c , J. SILVAª, R. QUEIRÓS b , J.A. SARAIVA b and P. TEIXEIRA a * a Laboratório Associado, Escola Superior de Biotecnologia, CBQF – Centro de Biotecnologia e Química Fina –, Universidade Católica Portuguesa, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto. Portugal b QOPNA, Departamento de Química, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro. Portugal c Nutrición y Bromatología Escuela de Ingenierías Agrarias, Universidad de Extremadura, Badajoz. Spain (Received: 16 June 2016; accepted: 5 October, 2016) The effect of sequential treatments of pressure (50–150 MPa, 10 ºC, 5 min) and temperature (57 ºC, 15 min) on the survival and bacteriocin production of Pediococcus acidilactici HA-6111-2 cells in the exponential growth phase was assessed. The growth curves were fitted with the modified Gompertz model, and the estimated maximum specific growth rate was considered to be pressure dependent. A delay in the maximum value of bacteriocin production was registered for more severe pressure conditions, but it was found more notorious for pressure followed by temperature treatments. At lower pressure intensity treatment, regardless of the application order, there was an enhancement of bacteriocin production per cell when compared to the control while maintaining the maximum production value. Bacteriocin production after the treatments can be described by an exponential model. Keywords: enhancement, bacteriocin production, Pediococcus acidilactici HA-6111-2, sequential treatments Biopreservation of foods could be an effective approach to solve microbial spoilage of food products, to reduce foodborne illness and to address the concern of consumers about the safety of chemical preservatives (PAPAGIANNI & ANASTASIADOU, 2009). Therefore, the search for natural food preservation methods is desirable and has received increasing attention in recent years. Previous reports suggest that bacteriocin-producing bacteria are one of the most promising natural food biopreservatives (LEROY et al., 2003), and lactic acid bacteria (LAB) with bacteriocin-producing abilities, such as pediococci strains, could be used in food manufacturing processes to control the growth of Listeria monocytogenes (DICKS et al., 2004) often encountered in fermented foods (FERREIRA et al., 2006). Application of bacteriocins as biopreservatives has proven to be effective along the food chain (e.g. veterinary, aquaculture, and agriculture) (DIEZ-GONZALEZ, 2007; HOLTSMARK et al., 2008; BAKKAL et al., 2012). Non-thermal processes, such as high hydrostatic pressure (HHP), can effectively enhance the safety and shelf life of several food products lacking chemical preservatives without compromising their organoleptic properties and nutritional qualities (RENDUELES et al., 2011; SHANKAR, 2014). HHP has been often described as an economical and technological alternative to thermal processes (MARTÍNEZ-RODRÍGUEZ et al., 2012; SHANKAR, 2014). In the hurdle concept, simultaneous or sequential techniques that act synergistically are applied to * To whom correspondence should be addressed. Phone: +351 22 558 0001; fax: +351 22 509 0351; e-mail: pcteixeira@porto.ucp.pt