反式肉桂醛与温和加热结合对复原婴幼儿牛乳中阪崎克罗诺肠杆菌的抑杀作用

研究反式肉桂醛与温和加热结合对复原婴幼儿牛乳中阪崎克罗诺肠杆菌的抑杀作用。将3 种阪崎克罗诺 肠杆菌的混合菌株（浓度约6.6（lg（CFU/mL）））接种于含有不同质量分数反式肉桂醛（0、0.1%、0.2%、0.3% 和0.4%）的复原婴幼儿牛乳样品中，将样品置于25、45、50、55 ℃培养，并在不同的时间点对样品中存活的阪崎 克罗诺肠杆菌涂布计数。为探究反式肉桂醛与温和加热结合的抑杀机制，实验利用LIVE/DEAD?细菌活性检测试 剂盒和场发射扫描电子显微镜探究细胞膜完整性及细胞形态。结果表明：0.4%的反式肉桂醛在25 ℃处理90 min、 45 ℃处理20 min、50 ℃处理10 min及55 ℃处理10 min使复原婴幼儿牛乳中阪崎克罗诺肠杆菌总数降低至检出限 以下。与反式肉桂醛及温和加热单独作用相比，反式肉桂醛结合温和加热对阪崎克罗诺肠杆菌有显著的抑杀效果 （P＜0.05），并且随温和加热温度的升高及反式肉桂醛质量分数的增加，效果更加明显。温和加热与反式肉桂醛 结合会影响细胞膜的通透性并使细胞破碎瓦解。以上结果表明：反式肉桂醛与温和加热结合有潜力在冲调乳粉过程 中应用，从而降低阪崎克罗诺肠杆菌的感染风险。

Inactivation of Cronobacter sakazakii in Reconstituted Infant Formula by Trans-Cinnamaldehyde Treatment Coupled with Mild Heating

The objective of this study was to determine the bactericidal effect of trans-cinnamaldehyde (TC) combined with mild heating on Cronobacter sakazakii in reconstituted infant formula. Reconstituted infant formula samples with various concentrations of TC (0, 0.1%, 0.2%, 0.3% and 0.4%) were inoculated with a mixture of three C. sakazakii strains (approximately 6.6(lg (CFU/ mL))) followed by incubation at 25, 45, 50 or 55 ℃. The surviving bacteria at different sampling times were enumerated. In order to elucidate the mode of action of the combined treatment, the cell membrane integrity and cell morphology were examined using a LIVE/DEAD? bacterial viability kit and a field emission scanning electron microscope, respectively. TC at 0.4% combined with heat treatment at 25 ℃ for 90 min, at 45 ℃ for 20 min, at 50 ℃ for 10 min or at 55 ℃ for 10 min reduced all pathogens to undetectable levels. Our results demonstrated that the combination of TC and heat treatment significantly reduced (P < 0.05) the number of C. sakazakii compared with either treatment alone, and this effect was dependent on both temperature and TC concentration. The combined treatment inactivated the pathogens partly by damaging cell membrane integrity, leading to cell disruption. These findings suggested that TC combined with mild heating may have potential application to control C. sakazakii infection during reconstitution of infant formula.