July 21/Hakozaki, Japan/Journal of Technology & Science -- According to a paper written by scientists at Kyushu University, "We developed a novel rapid hygrothermal pasteurization (RHP) method using saturated water vapor with a dew point of 100 degrees C. In the present study, the effects of RHP on microbiological quality and quality attributes such as color changes, firmness and ascorbic acid content on many fresh-cut fruits and vegetables (cabbage, cucumber, carrot, cherry tomato, bell pepper, strawberry, pineapple and melon) were investigated. The RHP was performed within a second by free-falling samples through a cylindrical processing chamber filled with steam."
"The RHP resulted in a 0.7-2.0 log order reduction in the numbers of naturally inoculated mesophilic bacteria. Furthermore, the RHP induced no significant changes in color and firmness of samples, except on the leafy vegetable, cabbage. Ascorbic acid was also retained approximately 80% and above. These results indicate that the RHP is a clean and effective method for decontaminating mesophilic bacteria on fresh fruits and vegetables with minimal changes in quality.
"Industrial relevance: In fresh-cut industry, an effective and risk-free decontamination technology is required for use in place of a conventional method, washing by chlorine that can produce carcinogenic chlorinated by-products. In this study, the rapid hygrothermal pasteurization (RHP) method using saturated water vapor was invented and their ability for applying minimal processing was evaluated. The results showed that RHP. without using chemicals, can reduce microorganism load and preserve quality attributes in many kinds of fresh-cut fruits and vegetables," wrote D. Tirawat and colleagues, Kyushu University.
The researchers concluded, "Therefore, RHP could be used as a novel method, which can be generally applicable to fresh-cut fruits and vegetables in the food industry."
Tirawat and colleagues published their study in Innovative Food Science & Emerging Technologies ("Development of Rapid Hygrothermal Pasteurization Using Saturated Water Vapor." Innovative Food Science & Emerging Technologies, 2010;11(3):458-463).
For more information, contact M. Shimoda, Kyushu University, Laboratory Food Processing Engineering, Division Food Biotechnology, Dept. of Bioscience & Biotechnology, School Agriculture, Higashi Ku, 6-10-1 Hakozaki, Fukuoka 8128581, Japan.
From the August 2, 2010, Prepared Foods E-dition