Day J B, Trujillo S, Hao Y Y D, Whiting R C
Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, HFS-712, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA.
J Food Prot. 2008 Nov;71(11):2208-12. doi: 10.4315/0362-028x-71.11.2208.
Francisella tularensis is a gram-negative bacterium that can cause gastrointestinal or oropharyngeal tularemia from ingestion of contaminated food or water. Despite the potential for accidental or intentional contamination of foods with F. tularensis, little information exists on the thermal stability of this organism in food matrices. In the present study, the thermal resistance of the live vaccine strain of F. tularensis in four food products (liquid infant formula, apple juice, mango juice, and orange juice) was investigated. D-values ranged from 12 s (57.5 degrees C) to 580 s (50 degrees C) in infant formula with a z-value of 4.37 degrees C. D-values in apple juice ranged from 8 s (57.5 degrees C) to 59 s (50 degrees C) with a z-value of 9.17 degrees C. The live vaccine strain did not survive at temperatures above 55 degrees C in mango juice and orange juice (>6-log inactivation). D-values at 55 to 47.5 degrees C were 15 to 59 s in mango juice and 16 to 105 s in orange juice with z-values of 9.28 and 12.30 degrees C, respectively. These results indicate that current pasteurization parameters used for destroying common foodborne bacterial pathogens are adequate for eliminating F. tularensis in the four foods tested. This study is the first to determine thermal inactivation of F. tularensis in specific foods and will permit comparisons with the thermal inactivation data of other more traditional foodborne pathogens.
土拉弗朗西斯菌是一种革兰氏阴性菌，可通过摄入受污染的食物或水导致胃肠道或口咽型兔热病。尽管存在土拉弗朗西斯菌意外或故意污染食品的可能性，但关于该菌在食品基质中的热稳定性的信息却很少。在本研究中，对土拉弗朗西斯菌活疫苗株在四种食品（液态婴儿配方奶粉、苹果汁、芒果汁和橙汁）中的热抗性进行了研究。在婴儿配方奶粉中，D值范围为12秒（57.5摄氏度）至580秒（50摄氏度），z值为4.37摄氏度。苹果汁中的D值范围为8秒（57.5摄氏度）至59秒（50摄氏度），z值为9.17摄氏度。在芒果汁和橙汁中，活疫苗株在高于55摄氏度的温度下无法存活（>6个对数级的灭活）。在55至47.5摄氏度时，芒果汁中的D值为15至59秒，橙汁中的D值为16至105秒，z值分别为9.28和12.30摄氏度。这些结果表明，目前用于杀灭常见食源性病原体的巴氏杀菌参数足以消除所测试的四种食品中的土拉弗朗西斯菌。本研究首次确定了土拉弗朗西斯菌在特定食品中的热灭活情况，并将允许与其他更传统食源性病原体的热灭活数据进行比较。
