Nano-Ag and lactate Na complex as food product protection

摘要

The aim of this study was the assessment of nano-silver (nano-Ag) antibacterial activity in foods and possibility to increase shelf life of cooked sausages. Nano-Ag was obtained by the reaction of AgNO3 with tannin and NaHCO3 at 71 °C for 2 h. The nano-Ag mean particle size was 30 nm according to the Rayleigh scattering data. The amino acid content was measured by the standard method. 0.05% nano-Ag water dispersion and the mixture of 0.05% nano-Ag and 1% sodium lactate were used. Nano-Ag antibacterial activity was tested microbiologically by growth zones of Aspergillus niger, Escherichia coli and Mucor heterosporum at 30 °C for 7 days. The free amino acid content monitoring was used to assess nano-Ag antibacterial activity in food. Addition of 0.5% of nano-Ag and sodium lactate to the sausages allowed to double the sausage shelf life at +4°C. The silver content in 3 mm layer under the sausage casings was low (<0.0001 mg/kg). The analysis of the microbial growth inhibition zones revealed the prominent antibacterial effect, especially for its synergistic composition with lactate. Thus, nano-Ag and its complex with lactate are the effective preserving agents for meat products.