Effects of sodium benzoate on the quality and aerobic stability of corn silage contaminated with Listeria monocytogenes

Abstract

This study was conducted to evaluate the effects of sodium benzoate on the microbial safety and fermentation quality of corn silage contaminated with Listeria monocytogenes. Corn plants were harvested during the milking stage, chopped into 1.5–2.0 cm segments, and ensiled in 1.5-liter containers at ambient temperature for 60 days. The experimental design included four treatment groups, each with four replicates: a control group (Group A), a group inoculated with L. monocytogenes (Group B), a group treated with both L. monocytogenes and sodium benzoate (Group C), and a group treated with sodium benzoate alone (Group D). L. monocytogenes was introduced to Groups B and C at a concentration of 10⁵ cfu/g, while sodium benzoate was added to Groups C and D at a concentration of 0.1 %. Following the 60-day ensiling period, samples were subjected to comprehensive chemical and microbiological analyses, as well as a 5-day aerobic stability test. Sodium benzoate supplementation enhanced the concentration of water-soluble carbohydrates and reduced levels of butyric acid, ethanol, and ammonia nitrogen (P < 0.001). Post-aerobic stability test results indicated that silages in Group D exhibited lower pH, CO₂ production, and yeast and mold counts significantly compared to the control group. No L. monocytogenes colony growth was observed in the silages during the microbiological analysis. These findings suggested that sodium benzoate could be a potent additive for improving both the fermentation quality and microbial safety of silages, offering significant benefits in the context of animal nutrition.