Microbial Profiling of Smer-Ripened Cheeses: Identification of Starter Cultures and Environmental Microbiota  
[PERSON]  
1 Department of Microbiology and Antibiotic Resistance, Veterinary Research Institute, Hudcova 296/70, 621 00 Brno, Czech Republic, [EMAIL_ADDRESS] (K.K. ): [EMAIL_ADDRESS] (M.E. ): [EMAIL_ADDRESS] (M.K. ): [PERSON](D.K. ): [EMAIL_ADDRESS] (V.B.) [PERSON]  
1 Department of Microbiology and Antibiotic Resistance, Veterinary Research Institute, Hudcova 296/70, 621 00 Brno, Czech Republic, [EMAIL_ADDRESS] (K.K. ): [PERSON]M.E. ): [PERSON]: [PERSON](D.K. ): [EMAIL_ADDRESS] (V.B.) [PERSON]  
1 Department of Microbiology and Antibiotic Resistance, Veterinary Research Institute, Hudcova 296/70, 621 00 Brno, Czech Republic, [EMAIL_ADDRESS] (K.K. ): [PERSON]M.E. ): [PERSON]: [EMAIL_ADDRESS] (D.K. ): [EMAIL_ADDRESS] (V.B.) Footnote 20: email: vladimir. cultures and thermophilic cultures. This classification is important for various types of cheese as temperature changes affect the behaviour of the bacteria and, thereby, the cheese-making and ripening processes. Mesophilic cultures include, for example, _Lactococcus lactis_ subsp. _lactis, Lactococcus lactis_ subsp. _cremoris_, some _Lactobacillus_ species and _Leuconostoc mesenteroides_[1; 2] and are intended for basic dairy products, such as cottage cheeses, fresh cheeses, semi-hard cheeses, and smear-ripened cheeses [1]. In contrast, thermophilic cultures include _Streptococcus salivarius_ subsp. _thermophilus_, _Lactobacillus helveticus_, and various subspecies of _Lactobacillus delbrueckii_ and are primarily used in the production of high-heat cheeses, pasta filata-type cheeses, mozzarella, and Dutch-type cheeses [1; 2]. In the production of smear-ripened chees, additional bacteria are deliberately applied to the cheese surface to develop the characteristic soft, moist rind [2]. Traditionally, a technique known as old-young smearing was used, which entails washing aged (old) cheese with a saline solution and subsequently using that solution to wash freshly made (young) cheese [2]. However, for safety reasons, this method has been replaced in commercial cheese production by using defined adjunct cultures of smear-associated bacteria. Commonly used adjunct bacteria include _Brevibacterium lintens_ (newly reclassified as _Brevibacterium aurantiacum_), _Brevibacterium casei_, _Staphylococcus equorum_, and occasionally _Microbacterium gubbeenense_, _Glutamicibacter_ spp. or _Corynebacterium casei_[2; 3]. These bacteria degrade proteins and fats in the cheese, leading to the production of aromatic compounds such as ammonia and sulphur, which contribute significantly to the distinctive aroma of the cheese. In addition to flavour enhancement, these bacteria also help soften the interior of the cheese, creating a creamy texture. Controlled application of adjunct bacterial cultures is crucial for achieving the characteristic appearance, including the reddish or orange rind, and for ensuring the safety and consistency of the cheese during the ripening process. The development of surface microbiota is further supported by yeasts that are applied by spraying onto the cheese surface. _Debaryomyces hansenii_ and other commonly used yeasts, such as _Geotrichum candidum_, _Kluyveromyces marxianus_, and _Candida Krusei_, decidify the cheese environment and thus promote the growth of smear bacteria [4]. Their proteolytic and lipolytic activity and the production of volatile compounds in yeast cultures also contribute to the organoleptic properties of the cheese [5]. In addition to starter and adjunct cultures, a variety of other microorganisms are present in the microbiota of smear-ripened cheeses [6; 7; 8]. Excluding pathogenic bacteria that may enter the production environment through raw milk or human carriers, these microorganisms, primarily found on the cheese surface, usually originate from the cheese plant environment, such as the brine bath or ageing surfaces [6; 7].