The aim of this study was evaluated the effect of selected bioactive substances and nanoparticles on the immunoreactivity of edible packages based on chitosan using the ELISA. The analysed protein was the tropomyosin. The results confirmed the presence of the tropomyosin (3.77 ± 0.79-5.75 ± 0.01 µg/g) in control samples. This study demonstrated that the bioactive substances in the form of grape (0.61 ± 0.34-0.43 ± 0.16 µg/g), blueberry (0.58 ± 0.32-0.39 ± 0.27 µg/g), and parsley extracts (2.09 ± 1.28-0.79 ± 0.40 µg/g) reduces immunoreactivity (p < 0.05) of the tropomyosin. The elder pollen had no significant effect (p > 0.05) on immunoreactivity. ZnO and TiO 2 nanoparticles also demonstrated immunoreactivity reduction (p < 0.05). The exception was silver nanoparticles, where the immunoreactivity increased with increasing concentration of grape extract (1.29 ± 0.01-5.47 ± 0.25 µg/g). The results confirmed the inhibitory effect of bioactive substances on the immunoreactivity of the used ELISA and also showed the need to consider immunoreactive substances when interpreting ELISA results.