Biodiversity of antifungal lactic acid bacteria isolated from raw milk samples from cow, ewe and goat over one-year period E. Delavenne, J. Mounier, F. Déniel, G. Barbier, G. Le Blay ⁎ UEB, France Université de Brest, EA3882 Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IFR148 ScInBioS, ESMISAB, Technopôle de Brest Iroise, 29280 Plouzané, France abstract article info Article history: Received 18 September 2011 Received in revised form 23 January 2012 Accepted 5 February 2012 Available online 12 February 2012 Keywords: Antifungal lactic acid bacteria Biodiversity Milk Cow Ewe Goat Antifungal lactic acid bacteria (ALAB) biodiversity was evaluated in raw milk from ewe, cow and goat over one year period. Lactic acid bacteria were enumerated using 8 semi-selective media, and systematically screened for their antifungal activity against 4 spoilage fungi commonly encountered in dairy products. Depending on the selective medium, between 0.05% (Elliker agar) and 5.5% (LAMVAB agar) screened colonies showed an antifungal activity. The great majority of these active colonies originated from cow (49%) and goat (43%) milks, whereas only 8% were isolated from ewe milk. Penicillium expansum was the most frequently inhibited fungus with 48.5% of colonies active against P. expansum among the 1235 isolated, followed by Mucor plumbeus with 30.6% of active colonies, Kluyveromyces lactis with only 12.1% of active colonies and Pichia anomala with 8.7% of active colonies. In the tested conditions, 94% of the sequenced active colonies belonged to Lactobacillus. Among them, targeted fungal species differed according to the Lactobacillus group, whose presence largely depended on year period and milk origin. The Lb. casei and Lb. reuteri groups, predominantly recovered in summer/fall, were overrepresented in the population targeting M. plumbeus, whereas isolates from the Lb. plantarum group, predominantly recovered in spring, were overrepresented in the population targeting K. lactis, the ones belonging to the Lb. buchneri group, predominantly recovered in spring, were overrepresented in the population targeting P. anomala. Raw milk, especially cow and goat milks from the summer/fall period appeared to be a productive reservoir for antifungal lactobacilli. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Milk and fermented dairy products are favorable environments for yeasts and molds growth that can be involved in fermentation or food spoilage (Rohm et al., 1992). They may ferment lactose and sucrose, utilize lactate, hydrolyze lipids and proteins and may grow at refrigera- tion temperatures (Huis in't Veld, 1996). Food spoilage fungi may be re- sponsible for production of gas, alcohol and undesirable aromatic compounds leading to flavor and texture defects, and economic losses (Rohm et al., 1992; Torkar and Vengust, 2008). Certain molds may also synthesize a wide panel of mycotoxins detrimental to the consumer health (Nelson, 1993; Pitt, 2000; Tantaoui-Elaraki and Khabbazi, 1984). To avoid fungal spoilage, numerous chemical preservatives are used, in- cluding organic acids, sodium benzoate, potassium sorbate, potassium benzoate and pimaricin (Brul and Coote, 1999; Smith and Hong-Shum, 2003). However, increasing resistances of fungi toward chemical preser- vatives, consumers demand for healthy and natural products and legis- lation evolution (Brul and Coote, 1999), have lead industrials to find new means of preservation such as bioprotective cultures like Micro- GARD® and HOLDBAC™ (Danisco, Niebûll GMBH, Germany). Lactic acid bacteria (LAB) are good candidates for fermented dairy food biopreservation. They are naturally present in yogurts, creams, fresh and mature cheeses and some of them possess antimicrobial ac- tivities (Pfeiler and Klaenhammer, 2007; Schnurer and Magnusson, 2005). Moreover, most of them belong to the qualified presumption of safety (QPS) and generally recognized as safe (GRAS) lists which insure their safe use in food (Bernardeau et al., 2008; Rossetti et al., 2009). Only few lactic acid bacteria such as enterococci remain ex- cluded from this status and require more vigilance because of their role in infection cases and spreading of antibiotic resistance genes (Mathur and Singh, 2005). Based on literature data, 0% to 75% LAB would have antifungal properties (De Muynck et al., 2004; Gerez, et al., 2009; Magnusson et al., 2003; Rouse et al., 2008; Schillinger and Villarreal, 2010; Valerio et al., 2009; Voulgari et al., 2010). This huge variation in the percentage of active LAB is explained by differences in methods for activity testing including medium utilized for LAB growth and targeted fungi. Until now, no study has systematically de- scribed, in a specific niche such as milk, the prevalence and the period- ical variations of antifungal LAB, tested with the same method, and compared these data with the total number of LAB present in the same sample. International Journal of Food Microbiology 155 (2012) 185–190 ⁎ Corresponding author at: Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, ESMISAB, Technopôle Brest-Iroise, 29280 Plouzané, France. Tel.: + 33 290915110; fax: + 33 290915101. E-mail address: gwenaelle.leblay@univ-brest.fr (G. Le Blay). 0168-1605/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.ijfoodmicro.2012.02.003 Contents lists available at SciVerse ScienceDirect International Journal of Food Microbiology journal homepage: www.elsevier.com/locate/ijfoodmicro