Inhibition of Listeria monocytogenes growth in Cheddar cheese by an anionic peptides-enriched extract from whey proteins Véronique Demers-Mathieu a , Sylvie F. Gauthier a, * , Michel Britten b , Ismaïl Fliss a , Gilles Robitaille b , Julie Jean a a Dairy Science and Technology (STELA) Research Center and Institute of Nutraceuticals and Functional Foods (INAF), Department of Food Sciences and Nutrition, Université Laval, Quebec city, QC, Canada G1V 0A6 b Agriculture et Agroalimentaire Canada, Centre de Recherche et de Développement sur les aliments, 3600 boul. Casavant O., St-Hyacinthe, QC, Canada J2S 8E3 article info Article history: Received 26 October 2012 Received in revised form 4 March 2013 Accepted 5 March 2013 abstract The efficacy of an anionic peptides-enriched extract (APEE), produced by nanofiltration of a tryptic hydrolysate from whey proteins, to inhibit the growth of Listeria innocua and Listeria monocytogenes in reconstituted Cheddar cheese was studied. The antimicrobial activity of APEE in reconstituted cheese was greater against L. monocytogenes than L. innocua and was higher in storage at 30  C than at 4  C. The combination of 20 mg g 1 of APEE and 1.75% salt/moisture (S/M) in cheeses incubated for 7 days at 30  C was the most efficient condition to inhibit the growth of Listeria. Using these conditions, L. monocytogenes counts were significantly reduced by 1.1 and 1.5 log cfu g 1 , compared with cheeses without APEE and prepared with lactococci at 1.75 and 3.5% S/M, respectively. These results suggest that antimicrobial anionic peptides from whey proteins can contribute to control pathogen in reduced-salt Cheddar cheeses. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction In the dairy industry, Listeria monocytogenes constitutes a leading safety problem since milk and dairy products, notably cheeses, are one of the sources of food-borne listeriosis (Donnelly, 2001; McLauchlin, Mitchell, Smerdon, & Jewell, 2004). The impor- tance of this psychotropic pathogen in dairy products results from its ability to grow or survive under a wide range of environmental conditions such as refrigeration temperature, low pH, and high salt concentrations (Doyle, 1988; Farber & Peterkin, 1991; Harvey & Gilmour, 1992). L. monocytogenes can survive for several weeks in a variety of cheeses, including those with low moisture content like Cheddar (Ryser & Marth, 1987). Elimination of L. monocytogenes in cheese is a major concern and represents an attractive research target. Food additives can be used against Listeria, but consumers are now seeking products that are made with natural ingredients, minimally processed and low in salt (Devlieghere, Vermeiren, & Debevere, 2004). Many studies have demonstrated that the control of Listeria growth in cheese can be achieved by bacteriocins used as natural food additives (Cleveland, Montville, Nes, & Chikindas, 2001), or by adding bacteriocin- producing lactic acid bacteria in the process of cheese-making (Eppert, Valdes-Stauder, Gotz, Busse, & Sherer, 1997; Reviriego, Fernández, & Rodríduez, 2007; Rodríguez, Arqués, Gaya, Nuñez, & Medina, 2001; Rodríguez, Gaya, Nuñez, & Medina, 1998). This later strategy allows the production of natural antimicrobial peptides in cheese without labelling the presence of antimicrobial agents on the package. The major bacteriocins used for such appli- cations are nisin from Lactococcus lactis strains, pediocin from Pediococcus acidilactici strains, and sakacins from Lactobacillus sakei strains (Devlieghere et al., 2004). Among these bacteriocins, nisin is commercially available and widely used in dairy industry as natural preservative, especially in cheeses (Thomas, Davies, Delves- Broughton, & Wimpenny, 1998). However, the effectiveness of added bacteriocins or bacteriocin-producing strains in cheese can be limited by a range of factors such as a limited spectrum of activity, spontaneous loss of bacteriocin synthesis (genetic instability), low diffusion in solid cheese matrices, poor adaptation of the culture to refrigeration temperature and cheese environment, inactivation through proteolytic enzymes or binding to food ingredients, low production level, and the emergence of bacteriocin-resistant bac- teria (Devlieghere et al., 2004). Consequently, the development of new natural antimicrobial preservatives to control Listeria growth in cheeses remains an important objective for the dairy industry. Antimicrobial peptides from milk proteins can be considered as safe and natural preservatives because they are generally obtained * Corresponding author. Tel.: þ1 418 656 2682. E-mail address: Sylvie.Gauthier@fsaa.ulaval.ca (S.F. Gauthier). Contents lists available at SciVerse ScienceDirect International Dairy Journal journal homepage: www.elsevier.com/locate/idairyj 0958-6946/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.idairyj.2013.03.008 International Dairy Journal 32 (2013) 6e12