Microbial Changes in Sweet Sorghum (Sorghum bicolor) Juices

摘要

Juice freshly expressed from Sorghum bicolor for making sweet sorghum syrup contained 10⁸ 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°C, and Lactobacillus plantarum was the dominant spoiling agent at 32°C, as determined by pure culture studies. Juice may be stored for 14 days at 4°C if promptly refrigerated.