Tiger nut milk and soymilk produce locally are usually contaminated with spoilage microorganisms and are not storage at ambient temperature. The present study aims to ensure the preservation of tiger nut milk and soymilk through the antimicrobial properties of the essential oil (EO) of Cymbopogon citratus under ambient temperature condition. Methods: The antibacterial activity was evaluated by agar diffusion and micro-dilution methods. Storage tests were performed under ambient temperature (25 °C) by incorporating tiger nut milk and soymilk with different doses of EO (0.05; 0.10; 0.15; 0.20; 0.25; 0.30; 0.35; 0.40; 0.45 and 0.50 (% v/v)), after which the physicochemical and microbiology characteristics were assessed. Results: The EO showed significant (p ˂ 0.05) inhibitory activity against Bacillus cereus LMG13569 (30.77 mm), Enterococcus faecalis ATCC19433 (22.81 mm), Listeria monocytogenes NCTC9863 (23.63 mm), Staphylococcus aureus ATCC25923 (32.60 mm),Micrococcus luteus LMG3293 (27.84 mm). The results of the shelf-life monitoring showed that the kinds of milk were free of total and thermotolerant coliforms, Bacillus spores and sulphite-reducing anaerobes spores. For the doses of 0.40 to 0.50 % of EO and after 3 days of storage, the total flora load ranged from 1.15x103to 8.5x102 CFU/ml (0.40 % EO); 1.15x103 to 6.5x102 CFU/ml (0.45 and 0.50 % EO) for the tiger nut milk. The total fungal flora ranged from 9.15x101 to 6.15x101 spores/ml (0.40 % EO); and 9.15x101 to 4.15x101 spores/ml (0.45 and 0.50 % EO). For the soymilk, the total flora load ranged from 1.25x103 to 8.5x102 CFU/ml (0.40 % EO); 1.25x103 to 6.5x102 CFU/ml (0.45 and 0.50 % EO) where the total fungal flora ranged from 102 to 6.15x101 spores/ml (0.40 % EO); 102 to 4.15x101 spores/ml (0.45 and 0.50 % EO). The pH ranged from 6.55 to 6.41 (tiger nut milk) and the acidity value between 0.128 and 0.131% lactic acid (soymilk). The results obtained indicated that the tiger nut milk and soymilk remained physically stable and its microbial quality complied with the standards set for spoilage flora and spores for 3 days under ambient temperature (25 °C). The stabilization concentration can be modulated for sensory acceptability.

Essential oil from Cymbopogon citratus tiger nut milk soymilk food spoilage stabilization