The smallest particle size (208 nm) showed the highest colorimetric response (90%), indicating PDA sizeenhanced sensitivity. Besides that, there is a relation between size and zeta potential: while particle sizeimproved (from 300 nm to 700 nm), zeta potential enlarged too (from −30 to −20). This effect could be explained by PDA aggregation over time, by high temperature effect or by Salmonella presence. The studyof zeta potential helped to understand that the interaction between Salmonella and antibody was through affinity between them. Therefore, understanding the parameters is important to improve PDA biosensorsto apply in food industry and laboratory areas.