Survival of four potential spoilage organisms was studied in tomato concentrates (22°, 28° and 34° Brix) stored at +7. 0 and −18 C for 4 months. In concentrates stored at −18 C, viable counts of Lactobacillus plantarum remained practically stable whereas those of Leuconostoc mesenteroides declined rapidly during the storage period, its death rate being reduced as the juice concentration was increased. Viable counts of Candida krusei and even more so of Torulopsis holmii, decreased progressively during frozen storage. In concentrates held at 0 C, viable counts of the four test organisms decreased during storage, regardless of the juice concentration. but at +7 C, for three out of the four test organisms, the ability to spoil the concentrates was dependent on the juice concentration.
1 Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 130-E, 1978 series.