Thermal Inactivation of Eupenicillium Javanicum Ascospores in Pineapple Juice: Effect of Temperature, Soluble Solids and Spore Age

Abstract

Food spoilage leading to food waste and substantial economic losses is a major issue for the food industry. The spoilage is often due to bacterial and fungal contamination in foods. Spores from microorganism pose a great concern since they can survive pasteurization and grow in specific foods. The obj1ectives of this work were to investigate the effect of temperature (T: 80-90°C), soluble solid concentration (11-20°Brix), and spore age (30-60 days) on the log reductions of Eupenicillium javanicum ascospores in pineapple juice. It was also carried out to estimate the first-order kinetic parameters (D and z-values) from the log survivor curves. Increasing the temperature from 80 to 90°C for 10 min increased the spore inactivation in 11°Brix pineapple juice by 6.4 log. For 5-log inactivation, increasing the percentage weight (% wt.) of sucrose from 11°Brix to 20°Brix at 90°C, increased the time needed to inactivate the spores by 2.6 min. Likewise, increasing the age of ascopores from 30 days to 60 days, also increased the time required by 16.7 min. The estimated D-values for 30-days old spores in 11°Brix juices were 19.84 min at 80°C, 4.99 min at 85°C and 1.45 min at 90°C, with z-values of 8.6-8.8°C. The results obtained provide useful data to design and predict pasteurization process targeting E. javanicum ascospores.