Studies on nectarines revealed that cold storage influences sugar and organic acid profiles, helping to maintain flavor and enhance antioxidant properties during storage [10]. Innovative technologies, like high-pressure processing (HPP), effectively extend the shelf life of fruit-based products while preserving sensory and microbiological stability. For example, research on aronia berry puree demonstrated that HPP significantly reduces microbial growth with minimal impact on phenolic content and antioxidant properties, enabling up to 8 weeks of refrigerated storage [5]. These findings underscore the crucial role of optimized storage conditions and advanced preservation technologies in ensuring the quality of fruit-based products. According to Commission Regulation (EC) No. 2073/2005 [11], fruit mousses, as ready-to-eat products, must meet certain microbiological criteria. For _Listeria monocytogenes_, ready-to-eat products supporting its growth must not exceed 100 CFU/g at the marketing stage or during shelf life. Products that do not support its growth maintain levels below this threshold throughout the shelf life. Furthermore, _Salmonella_ spp. cannot be detected in 25 g samples, whether for ready-to-eat products or other foods. In addition, fruit mousses should meet different requirements for levels of _Escherichia coli_ and other pathogens depending on product type and composition [2]. Minerals are important in infant nutrition for their functions, such as proper development and the formation of the immune system. Due to the presence of a wide variety of fruits and vegetables in infant mousses, these products are naturally rich in minerals, particularly zinc, copper, or selenium. It is assumed that minerals are not particularly sensitive to external factors; hence, the study of their content in ready-to-eat products is limited [4]. The level of bioactive compounds in fruit and vegetable mousses are determined by the diversity of their ingredients. Mousses with a more diverse composition, consisting of more fruits or vegetables, are richer in bioactive compounds and have higher antioxidant properties [12]. Bioactive compounds are present in small amounts in foods and contribute to health improvement or exhibit preventive effects against various diseases [13]. The most popular in this group are phenolic compounds, including phenolic acids, flavonoids, tannins, stilbenes, and lignans [14]. These compounds not only exhibit potent antioxidant activity but also have antimicrobial, anti-inflammatory, and antiproliferative functions [15]. Despite their significance, only a few authors have studied the loss of bioactive compounds in fruit mousses under varying storage conditions. [PERSON] et al. [16] studied the effect of high-pressure technology on changes in polyphenol and anthocyanin contents in fruit mousses during storage under refrigerated conditions (4 \({}^{\circ}\)C). The authors demonstrated an 11% reduction in anthocyanins in the mousses. Also, [PERSON] et al. [17] observed a smaller reduction in the total phenolic content compared to the total anthocyanin content in blue honeysuckle berry pure during storage at 20 \({}^{\circ}\)C without light exposure. Additionally, they noted that vitamin C losses were influenced by the specific variety of blue honeysuckle and the duration of storage. [PERSON] et al. [18] found the greatest decrease in the total phenolic content in a four-grain puree with banana and blueberry, characterized by a high pH and lower initial bioactive compound levels. In contrast, minimal changes were observed in mango-carrot-sea buckthorn puree and fruit-yogurt puree with biscuit, which had lower pH values and higher phenol content. In addition, no study has been conducted that also shows the microbiological properties of the mousses after storage. Therefore, the present study aimed to investigate the effect of the storage conditions on the content of selected bioactive compounds and the microbiological properties of fruit mousses for infant feeding.