Contents lists available at ScienceDirect LWT - Food Science and Technology journal homepage: www.elsevier.com/locate/lwt The microbiota of Kalathaki and Melichloro Greek artisanal cheeses comprises functional lactic acid bacteria Georgia Zoumpopoulou a,∗ , Konstantinos Papadimitriou a,1 , Voula Alexandraki a , Eleni Mavrogonatou b , Katerina Alexopoulou a,c , Rania Anastasiou a , Marina Georgalaki a , Dimitris Kletsas b , Efe Tsakalidou a , Efstathios Giaouris c a Laboratory of Dairy Research, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece b Laboratory of Cell Proliferation and Ageing, Institute of Biosciences and Applications, National Centre for Scientific Research “Demokritos”, Athens, Greece c Laboratory of Biology, Microbiology and Biotechnology of Foods, Department of Food Science and Nutrition, School of the Environment, University of the Aegean, Lemnos, Greece ARTICLEINFO Keywords: Artisanal cheeses Kalathaki cheese Melichloro cheese Microbiota Probiotic ABSTRACT Artisanal cheeses, in particular those prepared from raw milk, are the most commonly used ecosystems to mine microorganisms with both technological and human-health related potential. In the present study, the micro- biota of two Greek artisanal cheeses, the PDO Kalathaki and the non-PDO Melichloro, was explored via classical microbiological analysis. Lactic acid bacteria isolated mainly belonged to the genus Enterococcus (66%) and to a lesser degree to Pediococcus (15%), Leuconostoc (8%), Lactobacillus (6%) and Lactococcus (5%). From the 112 initial isolates, 32 were selected and studied for their probiotic potential, i.e. safety traits, survival under gas- trointestinal tract conditions, antimicrobial activity, adhesion, angiotensin I-converting enzyme inhibitory ac- tivity and immunomodulation of human monocytes. Two isolates, namely Lactobacillus brevis ACA-DC 1705 and Leuconostoc mesenteroides ACA-DC 1738, exhibited the most promising probiotic potential due to strong angio- tensin I-converting enzyme inhibitory activity and anti-infammatory modulation of immune cells, respectively, and, thus they could be used as adjuncts in novel functional products. 1. Introduction Fermented dairy foods, in particular cheeses and fermented milks, have been part of the human nutrition worldwide since ancient times, comprising an important part of a balanced diet. Despite the in- dustrialization of cheese making over a century ago, artisanal dairy products are constantly gaining the attention of consumers in recent years. Indeed, nowadays, consumption of artisanal and specialty cheeses is increasing and consumers are willing to pay more for high quality products. In particular, despite concerns about potential safety issues, consumers’ preference for raw milk cheeses is constantly growing because of their intense and diverse favor and aroma notes compared to pasteurized milk cheeses (Waldman & Kerr, 2015). Artisanal cheeses, in particular those prepared from raw milk, are the most commonly used ecosystems to discover new microorganisms with both technological and human-health related potential. Over the last decades, research tools have been developed, which allow the specifc targeting of individual genes and entire metabolic pathways responsible for the desired performance of a starter culture or a pro- biotic strain (De Vos & Hugenholtz, 2004). Nevertheless, innovations in the area of fermented foods and human health depend, besides on economic factors, also on a delicate balance between science and technology, safety and legislation, market needs and consumers’ atti- tude. This makes targeted screening of the natural microbial diversity of traditional dairy foods a more market-friendly approach than genetic engineering. Thus, the search for new starter cultures and probiotics is still relying on the screening of a large number of isolates, preferably selected from natural and spontaneously fermented foods, with respect to desired technological performance and health-related functionalities (Leroy & De Vuyst, 2004). Greece has a long tradition in small ruminant farming, i.e. sheep and goats, and thus sheep and goat milk make almost 60% of the total milk production while the remaining 40% is cow milk. The sheep and goat livestock extends to almost 10 million sheep and 5 million goats, https://doi.org/10.1016/j.lwt.2020.109570 Received 6 December 2019; Received in revised form 26 April 2020; Accepted 7 May 2020 ∗ Corresponding author. Laboratory of Dairy Research, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos, 118 55, Athens, Greece. E-mail address: gz@aua.gr (G. Zoumpopoulou). 1 Present address: Department of Food Science and Technology, University of Peloponnese, Kalamata, Greece. LWT - Food Science and Technology 130 (2020) 109570 Available online 14 May 2020 0023-6438/ © 2020 Elsevier Ltd. All rights reserved. T