Center for Meat Safety and Quality, Food Safety Cluster, Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523, USA.
J Food Prot. 2010 Mar;73(3):461-9. doi: 10.4315/0362-028x-73.3.461.
This study compared thermal inactivation of Escherichia coli O157:H7 in nonintact beefsteaks of different thicknesses by different cooking methods and appliances. Coarsely ground beef was inoculated with rifampin-resistant E. coli O157:H7 (eight-strain composite, 6 to 7 log CFU/g) and then mixed with sodium chloride (0.45%) plus sodium tripolyphosphate (0.23%); the total water added was 10%. The meat was stuffed into bags (10-cm diameter), semifrozen (-20 degrees C, 6 h), and cut into 1.5-, 2.5-, and 4.0-cm-thick steaks. Samples were then individually vacuum packaged, frozen (-20 degrees C, 42 h), and tempered (4 degrees C, 2.5 h) before cooking. Partially thawed (-2 +/- 1 degrees C) steaks were pan broiled (Presto electric skillet and Sanyo grill), double pan broiled (George Foreman grill), or roasted (Oster toaster oven and Magic Chef standard kitchen oven) to a geometric center temperature of 65 degrees C. Extent of pathogen inactivation decreased in order of roasting (2.0 to 4.2 log CFU/g) > pan broiling (1.6 to 2.8 log CFU/g) >/= double pan broiling (1.1 to 2.3 log CFU/g). Cooking of 4.0-cm-thick steaks required a longer time (19.8 to 65.0 min; variation was due to different cooking appliances), and caused greater reductions in counts (2.3 to 4.2 log CFU/g) than it did in thinner samples (1.1 to 2.9 log CFU/g). The time to reach the target temperature increased in order of George Foreman grill (3.9 to 19.8 min) < Oster toaster oven (11.3 to 45.0 min) < Presto electric skillet (16.3 to 55.0 min) < Sanyo grill (14.3 to 65.0 min) < standard kitchen oven (20.0 to 63.0 min); variation was due to steak thickness. Results indicated that increased steak thickness allowed greater inactivation of E. coli O157:H7, as time to reach the target internal temperature increased. Roasting in a kitchen oven was most effective for pathogen inactivation.
本研究比较了不同烹饪方法和炊具对不同厚度非完整牛肉牛排中大肠杆菌 O157:H7 的热失活动力学。将 rifampin 抗性大肠杆菌 O157:H7（八株复合菌，6 至 7 对数 CFU/g）粗磨牛肉接种，然后与氯化钠（0.45%）和三聚磷酸钠（0.23%）混合；添加的总水量为 10%。将肉装入袋中（直径 10 厘米），半冻结（-20°C，6 小时），切成 1.5、2.5 和 4.0 厘米厚的牛排。然后将样品分别进行真空包装，冷冻（-20°C，42 小时），在烹饪前进行调温（4°C，2.5 小时）。部分解冻（-2 +/- 1°C）的牛排用 Presto 电煎锅和 Sanyo 烤架进行单面煎，用 George Foreman 烤架进行双面煎，或用 Oster 烤面包机和 Magic Chef 标准厨房烤箱进行烘烤，使几何中心温度达到 65°C。病原体失活动力学按以下顺序递减：烘烤（2.0 至 4.2 对数 CFU/g）>单面煎（1.6 至 2.8 对数 CFU/g）>=双面煎（1.1 至 2.3 对数 CFU/g）。4.0 厘米厚牛排的烹饪时间较长（19.8 至 65.0 分钟；差异是由于不同的烹饪设备），并且比较薄的样本（1.1 至 2.9 对数 CFU/g）导致更大的计数减少（2.3 至 4.2 对数 CFU/g）。达到目标温度的时间顺序为 George Foreman 烤架（3.9 至 19.8 分钟）<Oster 烤面包机（11.3 至 45.0 分钟）<Presto 电煎锅（16.3 至 55.0 分钟）<Sanyo 烤架（14.3 至 65.0 分钟）<标准厨房烤箱（20.0 至 63.0 分钟）；差异是由于牛排的厚度。结果表明，随着达到目标内部温度的时间增加，牛排厚度的增加允许大肠杆菌 O157:H7 更大程度的失活。在厨房烤箱中烘烤对病原体失活最有效。
