The characteristics of Chinese household refrigerator microbial communities obtained from different geographical regions and different sampling sites.

Household refrigerators are essential for food preservation, yet their low-temperature environments can harbor diverse microbial communities, some of which pose potential pathogenic risks to stored food. The aim of this study was to explore the effects of different geographical regions, different sampling sites (inner wall of the cold storage compartment, door shelf, freezer compartment, and air in the cold storage compartment), service life, and sterilization function on microbial community structure in household refrigerators. Fifteen refrigerators from five cities (Beijing, Guangzhou, Harbin, Chengdu, and Qingdao), each with distinct dietary habits, were sampled at specified sites. Amplicon sequencing and statistical analyses revealed that Pseudomonas, Escherichia, Acinetobacter, Psychrobacter and Chryseobacterium were the dominant bacterial genera in refrigerators. While Malassezia, Cystofilobasidium, Pleurotus, Penicillium and Aspergillus were the main fungal genera in refrigerators. Significant differences in microbial community structure were observed between refrigerators from Qingdao and those from the other four cities. Among the four sampling sites, only the air samples from the cold storage compartment harbored a significantly distinct microbial community compared to the surface samples. No significant differences were found between communities in the cold storage and freezer compartments. This study provides the first systematic, national-scale characterization of the core microbial communities in Chinese household refrigerators. Our findings confirm that regional dietary habits are a key factor shaping these communities. The identification of potential foodborne pathogens and spoilage organisms offers a crucial theoretical basis for improving refrigerator hygiene and developing targeted antibacterial, preservation, and deodorization technologies.