Kim Hack-Youn, Kim Cheon-Jei, Han Sung Gu, Lee Sunah, Choi Kyoung-Hee, Yoon Yohan
Department of Animal Resources Science, Kongju National University, Yesan 340-702, Korea.
Department of Food Science and Biotechnology of Animal Resources, Konkuk University, Seoul 143-701, Korea.
Korean J Food Sci Anim Resour. 2014;34(1):20-5. doi: 10.5851/kosfa.2014.34.1.20. Epub 2014 Feb 28.
This study evaluated the effects of frankfurter fat content on Listeria monocytogenes resistance to heat stress and gastric fluid, and the Caco-2 cell invasion efficiency of the pathogen. A 10-strain mixture of L. monocytogenes was inoculated on frankfurters formulated with 10%, 20%, and 30% fat content (10%: F10, 20%: F20, 30%: F30) and stored at 10℃ for 30 d. The samples were analyzed for L. monocytogenes resistance to heat stress and a simulated gastric fluid challenge. The total bacteria and L. monocytogenes survival rates were measured on tryptic soy agar plus 0.6% yeast extract and Palcam agar, respectively. L. monocytogenes colonies inoculated on F10, F20, and F30 samples were used for a Caco-2 cell invasion assay. In general, no obvious differences were observed between the survival rates of total bacteria and L. monocytogenes grown on different fat contents under heat stress and gastric fluid challenge. However, L. monocytogenes obtained from the F30 samples had a significantly higher Caco-2 cell invasion efficiency than those in the F10 and F20 samples (p<0.05). These results indicate that although high fat content in food may not be related to L. monocytogenes resistance to heat stress and gastric fluid, it may increase the Caco-2 cell invasion efficiency of the pathogen.
本研究评估了法兰克福香肠脂肪含量对单核细胞增生李斯特菌耐热应激和胃液能力的影响，以及该病原菌对Caco-2细胞的侵袭效率。将10株单核细胞增生李斯特菌混合菌液接种到脂肪含量分别为10%、20%和30%的法兰克福香肠上（10%：F10，20%：F20，30%：F30），并在10℃下储存30天。分析样品中单核细胞增生李斯特菌的耐热应激能力和模拟胃液攻击后的情况。分别在胰蛋白胨大豆琼脂加0.6%酵母提取物和Palcam琼脂上测定总细菌和单核细胞增生李斯特菌的存活率。将接种在F10、F20和F30样品上的单核细胞增生李斯特菌菌落用于Caco-2细胞侵袭试验。总体而言，在热应激和胃液攻击下，不同脂肪含量的样品上生长的总细菌和单核细胞增生李斯特菌的存活率之间未观察到明显差异。然而，从F30样品中获得的单核细胞增生李斯特菌对Caco-2细胞的侵袭效率明显高于F10和F20样品中的菌株（p<0.05）。这些结果表明，尽管食品中的高脂肪含量可能与单核细胞增生李斯特菌的耐热应激和胃液能力无关，但可能会增加该病原菌对Caco-2细胞的侵袭效率。
