Weber-Frick C, Schmidt-Lorenz W
Laboratorium für Lebensmittel-Mikrobiologie, Eidgenössische Technische Hochschule, Zürich.
Zentralbl Bakteriol Mikrobiol Hyg B Umwelthyg Krankenhaushyg Arbeitshyg Prav Med. 1989 Feb;187(3):181-208.
In storage trials, the multiplication of gram negative bacteria was monitored by means of both colony counts and LPS-formation as determined by the three LAL tests methods (the Capillary test, the "Mini" Endotoxin test and the Coatest endotoxin method). The detection limits of the colony forming units which could be determined by the three LAL tests were initially set in model experiments in which beef (M. cleidooccipitalis) was variously inoculated with stationary-phase cells of Pseudomonas sp. previously grown at 30 degrees C. In all three methods, measurable amounts of LPS were possible only at colony counts above 10(3)/ml, g or cm2. The detection limits for colony counts of vacuum packed, aerobically stored beef muscle (Caput long. of M. triceps brachii) were found to lie between 1.0 x 10(3) and 1.0 x 10(4)/g for the Capillary test and the Coatest endotoxin method, and 5.0 x 10(4)/g for the "Mini" Endotoxin test. In the case of poultry carcasses the detection limits lay between 2.0 x 10(1) and 7.0 x 10(2)/cm2 and were thus considerably lower than for beef. With very low levels of bacterial loads, substrate interference in the LPS-LAL reaction must be taken into account. Linear regression analysis gave satisfactory correlation between the concentration of LPS and colony forming units for beef, poultry carcasses, ground beef and mixed salad. An acceptable proportionality was established only for beef and poultry carcasses. Potable water, stagnant for a fortnight in an experimental piping system and sampled at five different points, showed significant regrowth of oligocarbotolerant aquatic bacteria. However, only very low levels of LPS could be determined. All three LAL test methods can be recommended for rapid determination of the load of gram negative bacteria in meat and meat products.
在储存试验中，通过菌落计数以及由三种鲎试剂检测方法（毛细管试验、“微型”内毒素试验和科阿斯特内毒素法）测定的脂多糖形成来监测革兰氏阴性菌的增殖情况。三种鲎试剂检测方法能够测定的菌落形成单位的检测限，最初是在模型实验中设定的，在这些实验中，牛肉（枕下肌）用先前在30℃培养的铜绿假单胞菌的稳定期细胞进行不同程度的接种。在所有三种方法中，只有在菌落计数高于10³/ml、g或cm²时，才可能检测到可测量量的脂多糖。对于真空包装、有氧储存的牛肉肌肉（肱三头肌长头），毛细管试验和科阿斯特内毒素法的菌落计数检测限在1.0×10³至1.0×10⁴/g之间，“微型”内毒素试验的检测限为5.0×10⁴/g。对于家禽胴体，检测限在2.0×10¹至7.0×10²/cm²之间，因此明显低于牛肉。当细菌载量非常低时，必须考虑脂多糖 - 鲎试剂反应中的底物干扰。线性回归分析表明，牛肉、家禽胴体、碎牛肉和混合沙拉中脂多糖浓度与菌落形成单位之间具有良好的相关性。仅牛肉和家禽胴体建立了可接受的比例关系。在实验管道系统中静置两周并在五个不同点取样的饮用水，显示出耐寡碳水生细菌的显著再生长。然而，只能测定到非常低水平的脂多糖。所有三种鲎试剂检测方法均可推荐用于快速测定肉类和肉类产品中革兰氏阴性菌的载量。
