The objective of this experiment was to determine the effectiveness of Safesil (SF; 20% sodium benzoate, 10% potassium sorbate, 5% sodium nitrite) from Salinity, Sweden on improving aerobic stability of corn silage, and to evaluate its effects on fungi population by analysis of the internal transcribed space 1 (ITS1). Whole-plant corn was harvested at 39% DM, chopped, and untreated (CTRL) or treated with SF (2 L/t). Four replicated silos (7.5 L) were packed (224 kg of DM/m³) and ensiled for 85 d. Portions of CTRL and SF silages, and CTRL silage treated after ensiling with SF were used to make a total mixed ration (TMR) containing 40% corn silage, 20% alfalfa silage, and 40% grain mix. Samples were analyzed for microbial populations, fermentation profile, and aerobic stability (h before a 2°C increase above baseline after air exposure at 22°C). Three replicates of each fresh forage, and CTRL and SF silages were analyzed for fungal composition. DNA extraction, amplification of ITS1, library preparation, and sequencing, by Illumina MiSeq (San Diego, CA) platform, were performed by Research and Testing Laboratory (Lubbock, TX). Data were analyzed using JMP 12.0 and QIIME 1.9.1. SF had fewer yeasts (P < 0.01), lower pH (P < 0.01), and lower concentration of ethanol (P < 0.01) compared with CTRL. SF (241 h), TMR with SF silage (71 h), and TMR containing silage treated with SF after ensiling (82 h) had improved (P < 0.01) aerobic stability compared with CTRL silage (37 h) and CTRL TMR (41 h). Chao1 index indicated that fungal diversity was higher (P < 0.05) in fresh forage and decreased after ensiling. The relative abundance of genus Candida was lower (P < 0.01) in SF (6.3%) than CTRL (46.2%). The chemical additive greatly improved the aerobic stability of silage. Additionally, it has the potential to be used as a TMR stabilizer, if applied after ensiling. The improvement on aerobic stability by the chemical additive might be due to its capacity to reduce total numbers of yeasts, and to decrease specific populations of yeasts associated with lactate assimilation, such as Candida.