Detection of Formalin, Borax, and Pathogenic Bacteria in Processed Meat-Based Foods and Their Implications for Antimicrobial Resistance (AMR)

The misuse of formalin and borax as preservatives in processed meat and fish products has been long prohibited; however, their continued detection reflects persistent food safety challenges in Indonesia. This study aimed to analyze the presence of formalin, borax, and pathogenic bacteria in processed animal- and fish-based food products obtained from traditional markets in Semarang City. A descriptive research design was employed, with 27 samples—including meatballs, galantine, stuffed tofu, and sempolan—collected between July and August 2024. The detection of borax and formalin was performed using rapid test kits, while bacterial identification employed selective and differential media such as MacConkey Agar, Blood Agar, and Salmonella Shigella Agar. Results indicated that none of the samples contained borax, whereas formalin contamination was detected in 10 out of 27 samples (37.03%). Microbiological testing showed a high prevalence of pathogenic bacteria: Escherichia coli in 66.67% of samples, Salmonella spp. in 55.56%, and Staphylococcus aureus in 7.41%. Notably, all formalin-positive samples also harbored pathogenic bacteria, suggesting that the formalin concentrations were insufficient to inhibit microbial growth or that post-contamination occurred due to unhygienic handling. In conclusion, while borax was absent, the detection of formalin and pathogenic bacteria demonstrates that unsafe preservation practices and poor hygiene remain major public health risks. The coexistence of chemical and biological hazards in the same food products necessitates stricter enforcement of food safety regulations, routine monitoring, and enhanced education for food vendors to ensure consumer protection and public health safety.