Nutrition is an important aspect of the survival of all living beings in nature. Especially for humans, it is crucial that the foods they consume are produced, stored, marketed, and consumed according to hygiene rules. Microbial growth can occur in foods when sanitation is insufficient. The development and increase in the number of microorganisms in food can lead to food poisoning or food infections. The presence of bacteria that form biofilms on food surfaces is a significant problem for human health. Temperature, pH, humidity, nutrient content, and surface characteristics are factors that affect biofilm formation in foods. The development of bacteria that form biofilms is possible in foods sold on open-air market stalls, where hygiene and sanitation rules are disregarded. In this study, the isolation and identification of bacteria that form biofilms on various food products sold on open-air market stalls in Aydın Province were aimed. Bacteria were isolated from food surfaces in aseptic conditions using the Tryptic Soy Agar medium and incubated at 37°C for 24-48 hours. The DNA isolation of the isolated bacteria was performed using the 16S rDNA analysis, and PCR products were obtained. The PCR products were sent to a sequencing company (GATC BioTech, Germany) for sequencing. The Congo Red method was used to qualitatively determine the bacteria that form biofilms to analyze biofilm formation. According to this method, bacteria that form black colonies were evaluated as biofilm-positive. The bacteria that were evaluated as positive were subjected to quantitative analysis using the Microplate method. A total of 67 bacteria were isolated from various food samples and food stalls, of which 7 formed strong biofilms, and 2 formed moderate biofilms.