## 1 Introduction
[15] investigated the possibility of using essential oils obtained from various herbal plants to extend the shelf life of fresh chicken sausages that were packaged under aerobic conditions and stored at \(4\pm 1\)\({}^{\circ}\)C (20 days). In storage tests, the authors observed that clove oil had the best antioxidant effect in sausages and cassia essential oil was the most effective in preventing the growth of microorganisms. [PERSON] [16] investigated the effect of thyme essential oil on the shelf life of chicken meatballs during the refrigerated storage period (12 days, \(4\pm 1\)\({}^{\circ}\)C). Their study showed that thyme essential oil added to meat batter and applied to the surface of the product significantly slowed down lipid oxidation processes and the growth of many bacterial species, and thus extending the shelf life of meatballs. However, according to the author, an important criterion determining the usefulness of plant essential oils for meat products is the sensory acceptability of these products. Another study [17] proved that vacuum packaging material coated with rosemary oil could be added instead of rosemary essential oil in meat batter to extend the shelf life of refrigerated chicken meatballs. This type of packaging effectively inhibited microbial growth and lipid oxidation and improved the sensory properties of chicken meatballs. [PERSON] et al. [18] highlighted that _Ziziphora clinopodioides_ essential oil can be used as a natural antimicrobial alternative to synthetic chemical preservatives in RTE meat products such as raw chicken meatballs. In their study, meatballs treated with different concentrations of this essential oil showed better microbiological, chemical, and organoleptic properties compared to the control product until the end of the storage period (12 days). [PERSON] et al. [19] attempted to compare the effect of thyme oil and liquid smoke produced from beech sawdust on the quality parameters, including microbiological, physicochemical, and sensory characteristics, of chicken meatballs stored at refrigerated temperature for 12 days. Herbs and plant species are a good source of compounds with antioxidant and antimicrobial effects for food. Sage (_Salvia officinalis_ L.)--a species belonging to the Lamiaceae family--is one such valuable plant. Evidence confirms the use of sage by ancient humans for food and medicinal purposes. The wide applications of sage have been attributed to its unique properties including pleasant taste and preservative and therapeutic effects [20]. Research data show that sage contains many bioactive compounds, such as antioxidant [21; 22] and antibacterial ones [23; 24]. Study results demonstrate that sage preparations may allow for prolonging the storage stability of various meat products from pork [22; 25; 26; 27], beef [28], and poultry [29; 30]. Among the bioactive ingredients of sage, which have been proven to have both antioxidant and antibacterial properties, the following are mentioned: camphor, \(\alpha\)-thujone, and eucalypt [22; 23; 24]. Apart from this, sage preparations, such as water extract, essential oil, and ethanol extracts, have been successfully used in mechanically separated chicken meat that was vacuum-packed and stored in a frozen state (\(-18\)\({}^{\circ}\)C, 9 months) [31] and in vacuum-packed mechanically deboned chicken meat stored at refrigerated temperature (4-6\({}^{\circ}\)C, 14 days) [23]. The aim of the present work was to assess the effect of various sage preparations on quality parameters--including oxidation stability of lipids and microbial quality--of vacuum-packed chicken meatballs containing MSM from chickens during 14-day storage at +4 \(\pm\) 1\({}^{\circ}\)C. This study is one of its kind as no study has so far investigated the possibility of using various sage preparations obtained under laboratory conditions from the same raw material (dried sage leaves) to extend the storage stability and safety of this type of RTE meat products.