Rapid and simple on-site salmonella detection in food via direct sample loading using a lipopolysaccharide-imprinted polymer

Salmonella is a major foodborne pathogen that causes salmonellosis, which is characterized by symptoms such as diarrhea, fever, and abdominal cramps. Existing methods for detecting Salmonella, such as culture plating, ELISA, and PCR, are accurate but time-consuming and unsuitable for on-site applications. In this study, we developed a rapid and sensitive electrochemical sensor using a molecularly imprinted polymer (MIP) to detect Salmonella typhimurium (S. typhimurium) by targeting lipopolysaccharides (LPS). Polydopamine (PDA) was used as the polymer matrix because of its cost-efficiency and functional versatility. The sensor demonstrated high sensitivity and selectivity, with a detection limit of 10 CFU/mL and a linear response over the 10²-10⁸ CFU/mL range. The specificity of the sensor was validated against other gram-positive and gram-negative bacteria and showed no significant cross-reactivity. Furthermore, the sensor performed effectively in real food samples, including tap water, milk, and pork, without complex preprocessing. These results highlight the potential of the LPS-imprinted MIP sensor for practical on-site detection of S. typhimurium, improving food safety monitoring and preventing outbreaks in food-handling environments.