Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Stigebøjlen 4, Dk-1870 Frederiksberg C, Denmark.
J Food Prot. 2011 May;74(5):769-75. doi: 10.4315/0362-028X.JFP-10-338.
The objective of the study was to evaluate a new pathogen inactivation concept that combines application of pressurized steam simultaneously with high-power ultrasound through a series of nozzles. On skin and meat surfaces of pork jowl samples, counts of total viable bacteria were reduced by 1.1 log CFU/cm(2) after treatment for 1 s and by 3.3 log CFU/cm(2) after treatment for 4 s. The mean reduction of 1.7 to 3.3 log CFU/cm(2) on the skin surface was significantly higher than the reduction of 1.1 to 2.5 log CFU/cm(2) on the meat surface. The inactivation of Salmonella Typhimurium, Salmonella Derby, Salmonella Infantis, Yersinia enterocolitica, and a nonpathogenic Escherichia coli was studied on inoculated samples that were treated for 0.5 to 2.0 s. With one exception, no significant differences in reduction were observed among the bacterial types. After treatment for 0.5 s, the 0.9-to 1.5-log reductions of E. coli were significantly higher than the 0.4- to 1.1-log reductions for Salmonella and Y. enterocolitica. Overall, reductions increased by increasing treatment time; reductions were 0.4 to 1.5 log CFU/cm(2) after treatment for 0.5 s and 2.0 to 3.6 log CFU/cm(2) after treatment for 2 s. Reductions on the skin (1 to 3.6 log CFU/cm(2)) were significantly higher than reductions on the meat surface (1 to 2.5 log CFU/cm(2)). The reduced effect on the meat surface may be explained by greater protection of bacteria in deep structures at the muscle surface. No significant difference in reduction was observed between samples inoculated with 10(4) CFU/cm(2) and those inoculated with 10(7) CFU/cm(2), and cold storage of samples for 24 h at 5°C after steam-ultrasound treatment did not lead to changes in recovery of bacteria.
研究目的是评估一种新的病原体灭活概念，该概念将加压蒸汽与通过一系列喷嘴施加的高功率超声波相结合。在猪脸颊样本的皮肤和肉表面上，处理 1 秒后总活菌数减少了 1.1 对数 CFU/cm(2)，处理 4 秒后减少了 3.3 对数 CFU/cm(2)。在皮肤表面的平均减少 1.7 至 3.3 对数 CFU/cm(2)明显高于在肉表面的减少 1.1 至 2.5 对数 CFU/cm(2)。在接种的样本上研究了对肠炎沙门氏菌、德尔比沙门氏菌、婴儿沙门氏菌、小肠结肠炎耶尔森氏菌和非致病性大肠杆菌的灭活，处理时间为 0.5 至 2.0 秒。除了一个例外，在细菌类型之间没有观察到减少的显著差异。处理 0.5 秒后，大肠杆菌的 0.9 至 1.5 对数减少明显高于肠炎沙门氏菌和小肠结肠炎耶尔森氏菌的 0.4 至 1.1 对数减少。总体而言，随着处理时间的增加，减少量增加；处理 0.5 秒后减少 0.4 至 1.5 对数 CFU/cm(2)，处理 2 秒后减少 2.0 至 3.6 对数 CFU/cm(2)。皮肤表面的减少（1 至 3.6 对数 CFU/cm(2))明显高于肉表面的减少（1 至 2.5 对数 CFU/cm(2))。肌肉表面深层结构中细菌的更大保护可能解释了对肉表面的减少效果降低。在 10(4)CFU/cm(2)和 10(7)CFU/cm(2)接种的样本之间观察到的减少没有显著差异，并且蒸汽-超声处理后在 5°C 下将样本冷藏 24 小时不会导致细菌回收的变化。
