Application of modified magnesium-based layered double hydroxides in the control of microbial contamination

Magnesium-based hydrotalcite (MAL), aspartic acid (ASP)-loaded hydrotalcite (MALA) and ASP and Ag⁺ co-loaded hydrotalcite (MALAA) were prepared using the nucleation crystallisation method, and their structures and morphologies were characterised by means of X-ray diffraction and transmission electron microscopy, and both ASP and Ag⁺ were successfully loaded onto MAL with morphological changes. The effect of concentration on the growth inhibition of Staphylococcus aureus (S. aureus) by different materials was tested by colony counting method, and the results showed that the inhibition rate of MAL on S. aureus was only 5.8% when the concentration was 4 mg·mL^-1, while the inhibition rate of MALAA reached 99.7%. The bacterial inhibition mechanism of the modified magnesium-based hydrotalcite was analysed by inductively coupled plasma and UV-visible spectrophotometer techniques. The modified Mg-based hydrotalcite MALA was adsorbed on the negatively charged S. aureus by changing its morphology, increasing its contact area with bacteria and using electrostatic effect, and the introduction of Ag⁺ further increased the potential difference between the two, which facilitated the rupture of the cell membrane of S. aureus and decreased the integrity of the bacterial cell membrane, resulting in a significant increase in the content of extracellular metal ions (K⁺, Ca²⁺, and Mg²⁺) and protein content, and a significant increase in the content of MALA, and a significant increase in the content of MALA. content were significantly increased, and MALAA had a better bacterial inhibition effect. This kind of material is expected to be used in food, cosmetics and other packaging fields that require high microbiological safety.