Beverage challenge study with natural glycolipids

Commercially available lemon iced tea ('still beverage') and sparkling water containing grapefruit juice ('carbonated beverage') were inoculated with three groups of spoilage microorganisms. Three species were co-inoculated for each group. Only one group of microorganisms was inoculated in a sample. The inoculum for each species had a final concentration of 100 CFU/mL in the beverage. The still beverage had 6 treatments: negative control, 250 ppm sodium benzoate (SB250), 10 ppm natural glycolipids (NG10), 15 ppm natural glycolipids (NG15), 10 ppm natural glycolipids + 90 ppm dimethyldicarbonate (NG10VE90) and 5 ppm natural glycolipids + 238 ppm dimethyldicarbonate (NG5VE238). The carbonated beverage had 4 treatments: negative control, SB250, 5 ppm natural glycolipids (NG5) and NG15. Beverage samples were maintained for 12 weeks at ambient temperature. The sample from each treatment was enumerated biweekly. The microbial count was recorded as CFU/mL. For data visualization and statistical analysis, the data was log (base 10) transformed. A sample was considered spoiled when its plate count reached 1 million CFU/mL (equivalent to 6 log CFU/mL). This study was conducted using biological triplicates. Geometric mean and standard deviation of plate counts can be found in this data set. The data showed that the natural glycolipids could effectively inhibit the growth of spoilage yeasts and lactic acid bacteria in the beverages. The natural glycolipids was not lethal to filamentous molds.