Navigation

P3-07 Reduction of Vegetative Cells and Spores of Bacillus cereus in Fermented Soybean Products by Mild Heat Treatment

Wednesday, August 3, 2016
America's Center - St. Louis
Young Kyoung Park, Korea University, Sejong, Korea, The Republic of
Martti Tapani Sinnelä, Korea University, Sejong, Korea, The Republic of
Bo Young Byun, Korea University, Sejong, Korea, The Republic of
Kwangcheol Jeong, University of Florida, Gainesville, FL
Jae-Hyung Mah, Korea University, Sejong, Korea, The Republic of
Introduction: Korean traditional fermented soybean products (Doenjang and Cheonggukjang), contain abundant nutrients but have a risk of Bacillus cereus contamination during a series of unit manufacturing processes, including formulation, fermentation, and packaging processes. The viable cell counts of B. cereus in any type of traditional fermented soybean products should not exceed the guideline level of 4 log CFU/g in Korea (Food Code, Ministry of Food and Drug Safety).

Purpose: This study was performed to establish mild heat treatment condition which could reduce the growth of vegetative cells and spores of B. cereus without changes of organoleptic characteristics of Doenjang and Cheonggukjang.

Methods: Three B. cereus strains (KCTC 3624, KCTC 1012 and KCTC 1661) of type cultures and one strain (CH3) isolated from Cheonggukjang were used in this study. The effects of different heat treatments as functions of temperature and time (40-50ºC for 10-30 min for vegetative cells; 70-80ºC for 10-30 min for spores) were examined using B. cereus vegetative cells and spores inoculated into phosphate buffer, Doenjang and Cheonggukjang, respectively.

Results: In phosphate buffer, Doenjang and Cheonggukjang, a heat treatment of 50ºC for 30 min showed the strongest inhibition of the viability of B. cereus vegetative cells, resulting in reductions of 2.78-5.98 log CFU/g (phosphate buffer), 1.29-2.00 log CFU/g (Doenjang) and 0.21-0.49 log CFU/g (Cheonggukjang), respectively, as compared to control. Meanwhile, a heat treatment of 80ºC for 30 min showed the strongest inhibition of the viability of B. cereus spores, resulting in reductions of 1.39-6.07 log CFU/g (phosphate buffer), 0.68-1.50 log CFU/g (Doenjang) and 0.23-0.31 log CFU/g (Cheonggukjang), respectively, as compared to control.

Significance: These data support the possibility of successful application of mild thermal treatment to fermented soybean products for reducing the risk of B. cereus contamination.

Back to: Poster Session 3 – Antimicrobials, Laboratory and Detection Methods, Microbial Food Spoilage, Modeling and Risk Assessment, Retail and Food Service Safety and Sanitation
<< Previous Abstract | Next Abstract >>