Department of Pharmacognosy, School of Pharmacy, The University of Mississippi, University, MS 38677-1848, USA.
Int J Food Microbiol. 2010 Mar 31;138(1-2):63-70. doi: 10.1016/j.ijfoodmicro.2009.11.012. Epub 2009 Nov 20.
An innovative approach to Post-Harvest Processing (PHP) of oysters is introduced focusing on the effects of supercritical carbon dioxide (scCO(2)) on bacterial contaminants trapped in the digestive system of oysters. Oysters were exposed to scCO(2) under two conditions: (1) 100 bar and 37 degrees C for 30 min and (2) 172 bar and 60 degrees C for 60 min. Using FDA standard guidelines for food analysis, variations in the Aerobic Plate Count (APC) were assessed. It was established that exposing oysters to CO(2) at 100 bar and 37 degrees C for 30 min and at 172 bar and 60 degrees C for 60 min induced 2-log and 3-log reductions in the APC respectively. The decrease in the microbial load as a result of treatment with scCO(2) was found to be significant (P=0.002). A release of adductor muscles from the shell was noted in oysters treated at 172 bar and 60 degrees C for 60 min; this was not the case for oysters treated at 100 bar and 37 degrees C for 30 min. A blind study allowing sensory analysis of treated vs. untreated oysters was also completed and no significant change in the physical appearance, smell, or texture was recorded. In this paper, we also report the effect of scCO(2) on several bacterial isolates, including a referenced ATCC strain of a non-pathogenic Vibrio (Vibrio fischeri) as well as several other bacterial isolates cultured from oyster' tissues and found to share biochemical features common to pathogenic Vibrio strains. A complete inactivation (minimum 7-log reduction) was achieved with these latter bacterial isolates. A 6-log reduction was observed with V. fischeri.
一种新颖的牡蛎采后处理（PHP）方法，主要关注超临界二氧化碳（scCO2）对牡蛎消化系统中捕获的细菌污染物的影响。将牡蛎暴露于两种条件下的 scCO2 中：（1）100 巴和 37°C 下 30 分钟；（2）172 巴和 60°C 下 60 分钟。使用食品分析的 FDA 标准指南，评估了需氧平板计数（APC）的变化。结果表明，将牡蛎暴露于 CO2 中，在 100 巴和 37°C 下 30 分钟，在 172 巴和 60°C 下 60 分钟，分别使 APC 减少 2 对数和 3 对数。发现由于 scCO2 处理导致微生物负荷减少具有显著意义（P=0.002）。在 172 巴和 60°C 下处理 60 分钟的牡蛎中，注意到闭壳肌从壳中释放出来；而在 100 巴和 37°C 下处理 30 分钟的牡蛎中则没有这种情况。还完成了一项允许对处理过和未处理过的牡蛎进行感官分析的盲法研究，没有记录到物理外观、气味或质地有明显变化。在本文中，我们还报告了 scCO2 对几种细菌分离物的影响，包括非致病性弧菌（Vibrio fischeri）的参考 ATCC 菌株以及从牡蛎组织中培养出的几种其他细菌分离物，这些分离物具有与致病性弧菌菌株共同的生化特征。这些后者细菌分离物实现了完全失活（最小减少 7 对数）。V. fischeri 观察到减少 6 对数。
