Rajkowski Kathleen T
Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
J Food Prot. 2008 Nov;71(11):2278-82. doi: 10.4315/0362-028x-71.11.2278.
With the popularity of catfish and tilapia in the healthy diet, the consumption and harvesting of farm-raised finfish have increased. Since 1987 the pathogenic bacterium Listeria monocytogenes has been isolated from seafood, particularly farm-raised catfish in the United States. Seafood isolates of L. monocytogenes are now available. In order to maintain the raw finfish product, nonthermal interventions to remove bacterial pathogens need to be evaluated using these isolates. A nonthermal intervention process, irradiation, was used to determine the destruct values of the L. monocytogenes seafood isolates along with a nonpathogenic Listeria strain and an L. monocytogenes strain previously studied. The irradiation destruct values were obtained for each individual isolate inoculated on raw and frozen catfish or tilapia irradiated at 4 or -10 degrees C. The Dradiation values obtained for L. monocytogenes inoculated on raw or frozen catfish did not differ (P > 0.05) from the values obtained for strains inoculated on the raw or frozen tilapia. The Dradiation-values ranged from 0.48 to 0.85 kGy, with an average of 0.62 +/- 0.09 kGy, which is typical for Listeria. The data obtained have identified a multi-isolate cocktail that can be used for future radiation inactivation studies for L. monocytogenes inoculated on finfish.
随着鲶鱼和罗非鱼在健康饮食中日益普及，养殖有鳍鱼类的消费量和捕捞量都有所增加。自1987年以来，已从海产品中分离出致病性单核细胞增生李斯特菌，尤其是在美国养殖的鲶鱼中。现在已有单核细胞增生李斯特菌的海产品分离株。为了保存生的有鳍鱼类产品，需要使用这些分离株评估去除细菌病原体的非热干预措施。采用一种非热干预方法——辐照，来确定单核细胞增生李斯特菌海产品分离株以及一株非致病性李斯特菌菌株和一株先前研究过的单核细胞增生李斯特菌菌株的致死剂量值。对接种在生的和冷冻的鲶鱼或罗非鱼上、分别在4℃或-10℃下辐照的每一株分离株，都获得了辐照致死剂量值。接种在生的或冷冻鲶鱼上的单核细胞增生李斯特菌所获得的辐照致死剂量值，与接种在生的或冷冻罗非鱼上的菌株所获得的值没有差异（P>0.05）。辐照致死剂量值范围为0.48至0.85千戈瑞，平均为0.62±0.09千戈瑞，这对李斯特菌来说是典型的。所获得的数据确定了一种多分离株混合菌液，可用于未来对接种在有鳍鱼类上的单核细胞增生李斯特菌进行辐射灭活研究。
