Shelef Leora A
Department of Nutrition and Food Science, Wayne State University, Detroit, Michigan 48202.
J Food Prot. 1989 Jun;52(6):379-383. doi: 10.4315/0362-028X-52.6.379.
Survival and growth of three Listeria monocytogenes strains (Scott A, Brie-1, and ATCC 35152) were studied in ground beef or liver during storage from freshness to spoilage at 4 and 25°C. Cells were enumerated on Plate Count Agar, Trypticase Soy Agar, and selective media, including McBride Listeria Agar (MLA), Cyclohexanedione Nalidixic Acid Phenylethanol Agar (CNPA), LiCl Phenylethanol Moxalactam Agar (LPM), and LPM with potassium tellurite (LPMT). Aerobic natural microflora in the fresh uninoculated samples ranged from 10 to 10 CFU/g, and L. monocytogenes inocula were ca. 10 or 10 CFU/g. Total aerobes after 2 weeks at 4°C were >10 or >10/g in meat or liver respectively, while recovered numbers of L. monocytogenes remained unchanged during a storage of over 30 d in either ground meat or liver. Samples stored at 25°C confirmed recovery but absence of multiplication of the organism. LPM or LPMT provided the best selective environment for direct plating of meat. Despite differences in composition and spoilage pattern of meat and liver, no difference was observed in the fate of L. monocytogenes in these foods.
研究了三种单核细胞增生李斯特菌菌株（斯科特A、布里-1和ATCC 35152）在4°C和25°C下从新鲜到变质的储存过程中在绞碎牛肉或肝脏中的存活和生长情况。在平板计数琼脂、胰蛋白胨大豆琼脂和选择性培养基上对细胞进行计数，这些选择性培养基包括麦克布赖德李斯特菌琼脂（MLA）、环己二酮萘啶酸苯乙醇琼脂（CNPA）、氯化锂苯乙醇莫拉酰胺琼脂（LPM）和含亚碲酸钾的LPM（LPMT）。新鲜未接种样品中的需氧自然微生物群范围为10⁴至10⁷CFU/g，单核细胞增生李斯特菌接种量约为10³或10⁴CFU/g。在4°C下储存2周后，肉类或肝脏中的总需氧菌分别>10⁷或>10⁸/g，而在绞碎肉或肝脏中储存超过30天期间，单核细胞增生李斯特菌的回收数量保持不变。在25°C下储存的样品证实该菌可回收但未增殖。LPM或LPMT为肉类的直接平板接种提供了最佳的选择环境。尽管肉类和肝脏的组成和腐败模式存在差异，但在这些食品中单核细胞增生李斯特菌的命运未观察到差异。
