Aspergillus niger time to growth in dried tomatoes

Individual and combined effects of aw and incorporation of selected concentrations of Mexican oregano essential oil on the time to growth (TTG) of Aspergillus niger intentionally inoculated into dried tomatoes were studied during storage at 25°C for 100days. For aw 0.96, 1000ppm of Mexican oregano essential oil inhibited A. niger growth during 100days, whereas 500ppm were sufficient at aw 0.91 and 250ppm for tomatoes with aw 0.78. A. niger growth was evident at different incubation times depending on tested tomato aw and concentration of essential oil; these data were utilized to model TTG. Regression analysis revealed good agreement between experimental and predicted data with a correlation coefficient higher than 0.98. Analysis of mold growth data through TTG models makes possible to include observations detected as no growth and can be utilized to predict mold time to growth for specific preservation factor combinations or to select preservation factor levels for an expected shelf-life based on A. niger growth. •Time-to-growth (TTG) modeling allows to predict mold spoilage in dried tomatoes.•Mexican oregano essential oil can be used as an antifungal agent in dried tomatoes.•Aspergillus niger growth in dried tomatoes depends on water activity and oregano essential oil concentration.