Microbial Changes in Sweet Sorghum (Sorghum bicolor) Juices

Juice freshly expressed from Sorghum bicolor for making sweet sorghum syrup contained 10 microorganisms per ml. The dominant bacterium was Leuconostoc mesenteroides, followed by gram-negative rods. Lactobacilli, yeasts, and nonfecal coliform bacteria each comprised about 1% of the microbial population. Spoilage of juice, manifested by a sour odor, discoloration, and foaming, occurred between 5 and 12 h at ambient temperatures. Spoilage was correlated with a drop in pH from 4.9 to 4.5 L. mesenteroides was the dominant spoiling agent at 20 degrees C, and Lactobacillus plantarum was the dominant spoiling agent at 32 degrees C, as determined by pure culture studies. Juice may be stored for 14 days at 4 degrees C if promptly refrigerated.