Liu Xiaoji, Miller Petr, Basu Urmila, McMullen Lynn M
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
FEMS Microbiol Lett. 2014 Nov;360(2):152-6. doi: 10.1111/1574-6968.12599. Epub 2014 Oct 14.
The aim of this study was to examine the filament formation and differential gene expression of Listeria monocytogenes 08-5923 grown on refrigerated vacuum-packaged ham products with various NaCl concentrations. Filament formation of L. monocytogenes was observed on ham products with 1.35% and 2.35% NaCl, which was monitored using flow cytometry by measuring forward light scatter. Quantitative real-time PCR was used to study the differential expression of genes in filamented cells of L. monocytogenes grown on hams following 2 or 3 months of storage at 4 °C. The genes involved in cell division (ftsX/lmo2506), cell wall synthesis (murZ/lmo2552), and NADPH production (gnd/lmo1376) were significantly downregulated in filamented cells of L. monocytogenes grown on ham with 2.35% NaCl stored at 4 °C. To our knowledge, this study reports the first evidence of filament formation of Listeria grown on meat products, which could impact the food safety risk and tolerance levels of L. monocytogenes set by regulatory agencies.
本研究的目的是检测在不同NaCl浓度的冷藏真空包装火腿产品上生长的单增李斯特菌08 - 5923的丝状形成及差异基因表达。在NaCl含量为1.35%和2.35%的火腿产品上观察到了单增李斯特菌的丝状形成，通过流式细胞术测量前向光散射对其进行监测。采用定量实时PCR研究在4℃储存2或3个月后的火腿上生长的单增李斯特菌丝状细胞中基因的差异表达。在4℃储存的NaCl含量为2.35%的火腿上生长的单增李斯特菌丝状细胞中，参与细胞分裂（ftsX/lmo2506）、细胞壁合成（murZ/lmo2552）和NADPH生成（gnd/lmo1376）的基因显著下调。据我们所知，本研究首次报道了肉制品上生长的李斯特菌丝状形成的证据，这可能会影响监管机构设定的单增李斯特菌的食品安全风险和耐受水平。
