Application of iron oxide nanoparticles @ polydopamine-nisin composites to the inactivation of Alicyclobacillus acidoterrestris in apple juice

Iron oxide nanoparticles (IONPs) modified with polydopamine were covalently immobilized with nisin to inhibit the growth of Alicyclobacillus acidoterrestris in apple juice. The minimum bactericidal concentration (MBC) of IONPs @ pDA-nisin composites against Alicyclobacillus acidoterrestris cells and spores in three kinds of apple juice were 1.25 mg/mL and 2.5 mg/mL, respectively. The concentration of cells and spores decreased from 10(6) to 10 CFU/mL in apple juice after pretreatment with the composites at the concentration of 20 mg/mL for 10 min. Meanwhile, the investigation of the content of polyphenols, organic acids, volatile compounds and sugars indicated that there was no significant influence of the composites on the apple juices. The results of cytotoxicity (HepG2, Caco 2, SH-SY5Y, and BV2 cells) and acute toxicity test demonstrated the biosecurity and nontoxicity of the composites, which suggested that it was promising to apply the proposed composites to apple juice industry for the control of Alicyclobacillus acidoterrestris pollution.