U.S. Food and Drug Administration, Division of Seafood Science and Technology, Gulf Coast Seafood Laboratory, Dauphin Island, Alabama 36528, USA.
J Food Prot. 2009 Oct;72(10):2110-3. doi: 10.4315/0362-028x-72.10.2110.
From June through October 2004, the U.S. Food and Drug Administration collected oysters (61 samples) that had been subjected to postharvest processing (PHP) methods, including mild heat treatment, freezing, and high hydrostatic pressure, from processors and retail markets in various states to determine Vibrio vulnificus and V. parahaemolyticus levels. Presence in a 25-g sample and most probable number (MPN) using standard enrichment and selective isolation procedures were utilized. Suspect colonies were isolated and identified using DNA probe colony hybridization. Neither species of vibrio was detected in 25-g portions of most samples regardless of the PHP. The lowest frequency of isolation of either pathogen (<10%) was observed with the mild heat process. Few (12 to 13%) frozen samples collected at the processor but not at retail contained >30 MPN/g of either pathogen. The mean levels of either organism in PHP oysters observed in the present study were 5 to 6 log less than in unprocessed raw Gulf Coast oysters. Of the 70 V. vulnificus isolates examined, only 5 possessed the putative virulence marker, type B 16S rRNA. Neither the thermostable direct hemolysin (tdh) nor the tdh-related hemolysin (trh) virulence gene was detected in any of the 40 V. parahaemolyticus isolates examined in the present study. These data suggest that if there is any selective advantage to pathogenic strains of V. vulnificus and V. parahaemolyticus, these differences are minimal. These results indicate that all PHP treatments greatly reduce exposure of V. vulnificus and V. parahaemolyticus to raw-oyster consumers. Consequently, these PHP oysters pose a much lower risk of illness to consumers due to these pathogens.
2004 年 6 月至 10 月期间，美国食品和药物管理局从不同州的加工商和零售市场收集了经过收获后处理（PHP）方法处理的牡蛎（61 个样本），包括轻度热处理、冷冻和高压处理，以确定创伤弧菌和副溶血性弧菌的水平。使用标准的富集和选择性分离程序检测 25 克样本中的存在和最可能数（MPN）。使用 DNA 探针菌落杂交法分离和鉴定可疑菌落。无论 PHP 如何，大多数样本的 25 克部分均未检测到两种弧菌。轻度热处理过程中观察到两种病原体的分离率最低（<10%）。在加工厂收集但不在零售处收集的少数（12 至 13%）冷冻样本中，每克含有>30 MPN/g 的病原体。在本研究中观察到的 PHP 牡蛎中两种生物体的平均水平比未经处理的海湾沿岸生牡蛎低 5 至 6 个对数。在所检查的 70 个创伤弧菌分离物中，只有 5 个具有假定的毒力标记物，B 型 16S rRNA。在所检查的 40 个副溶血性弧菌分离物中，均未检测到耐热直接溶血素（tdh）或 tdh 相关溶血素（trh）毒力基因。这些数据表明，如果创伤弧菌和副溶血性弧菌的致病性菌株有任何选择优势，那么这些差异是微不足道的。这些结果表明，所有 PHP 处理都大大降低了生牡蛎消费者接触创伤弧菌和副溶血性弧菌的风险。因此，由于这些病原体，这些 PHP 牡蛎对消费者的患病风险要低得多。
