<jats:p xml:lang="en">The purpose of this study is to investigate the potential alternative use of kefir and its derived components in the biocontrol of fungi that cause economic losses during the harvesting and storage of fruits. The antifungal properties of kefir and its derived components (the non-protein liquid fraction of kefir, kefiran, and yeast cells isolated from kefir) were examined using the disk diffusion method, and the minimum inhibitory concentration (MIC) against naturally occurring fungi during the storage of hazelnuts, oranges, and apples were determined. Fungal isolates obtained from different fruits were identified as Aspergillus niger, Penicillium digitatum, and Penicillium expansum through 18S rRNA Polymerase Chain Reaction. The inhibition zones of A. niger, P. digitatum, and P. expansum were evaluated using the disk diffusion method. The minimum inhibitory concentrations (MICs) for kefir against A. niger, P. digitatum, and P. italicum were found to be 0.4, 0.2, and 0.25 µg mL-1, respectively. The effectiveness of these applications was analyzed using a technique known as TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution). With the development of the results of this study, alternative biocontrol applications using kefir and its components could be developed to prevent fungi-related microbial spoilage, providing an alternative to chemical treatments.</jats:p>