ORIGINAL RESEARCH Application of indigenous strains of lactic acid bacteria for semi-industrial production of autochthonous Montenegrin Njegu  si cheese ALEKSANDRA MARTINOVIC, 1,2 * JUDITH NARVHUS, 2 ROGER K ABRAHAMSEN, 2 HILDE M ØSTLIE 2 and SIV B SKEIE 2 1 Faculty of Food Technology, Food Safety and Ecology, University of Donja Gorica, Donja Gorica bb., Podgorica 81000, Montenegro, and 2 Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, Aas N-1432, Norway Most of the traditional dairy products of south-eastern Europe are produced from unpasteurised milk without addition of selected starter cultures. These artisanal products have an interesting bio- diversity of indigenous microbiota. In Montenegro, one of the most popular traditional cheeses is Njegu  si cheese, belonging to the group of hard cheeses. Most of the cheeses are produced from ewes’ milk, but cows’ milk is also widely used. In Montenegro, there are no existing legal regula- tions defining the specificities of the production or the raw material used for the production of auto- chthonous food products. Therefore, the producers make the decision about what type of milk to use for cheese production. One of the priorities of the food producers in Montenegro is to obtain a larger scale, standardised production of traditional food products, which are of good quality and considered safe for the consumers. Therefore, in this study, indigenous strains of lactic acid bacte- ria isolated from various Montenegrin artisanal dairy products were tested as starter cultures for the production of Njegu  si cheese. Three isolates were selected and used as starter cultures in pilot plant experiments for the production of Njegu  si cheese. When applying an adequate combination of added bacterial strains as starters, the flavour of Njegu  si cheese, produced under pilot plant condi- tions, was comparable to that of the artisanal origin. Keywords Lactic acid bacteria, Njegu  si cheese, Traditional cheese production. INTRODUCTION Farmhouse fermented milk products are made using traditional technology developed in the country or region where the food is produced, and can be considered as part of the country’s cultural heritage. The natural microbiota isolated from farmhouse fermented milk products repre- sents a reservoir for obtaining strains with speci- fic features, which could be used as starter cultures in the dairy industry (Marilley and Casey 2004). Such strains may differ in many important properties, such as their rate and extent of acid production, sensitivity to bacterio- phage infection and ability to degrade casein. Montenegro is a small country, but due to its climate and geographical characteristics, it has a high diversity of traditional food products, including dairy products (Dozet et al. 1996). In the various regions of the country, different tra- ditional dairy foods are produced, such as soft, semihard and pasta filata cheeses, and fermented milk. The type of product made is influenced by climate conditions and type of the livestock breed in the different areas. One of the most appreciated and best known traditional Montenegrin cheeses is Njegu  si cheese, dating back to the time of the Roman Empire when Montenegro was a part of Doclea, and the cheese was distributed to Rome under the name ‘Caseus Doclestes’ (Marke  s 1973). Its production was recorded later in the travelogue of Heinrich Stieglitz when describing the hospi- tality of the people from Njegu  si and the extre- mely good taste of the cheese that he was served (Stieglitz 1841). *Author for correspondence. E-mail: aleksandra.martinovic@ udg.edu.me © 2018 Society of Dairy Technology Vol 71 International Journal of Dairy Technology 1 doi: 10.1111/1471-0307.12480