Woerner D R, Ransom J R, Sofos J N, Dewell G A, Smith G C, Salman M D, Belk K E
Center for Red Meat Safety, Colorado State University, Fort Collins, Colorado 80523, USA.
J Food Prot. 2006 Dec;69(12):2824-7. doi: 10.4315/0362-028x-69.12.2824.
Prevalence of Escherichia coli O157 on cattle entering the slaughter floor may range from 10 to > 70%. This study was conducted to determine the effect of E. coli O157 prevalence in fecal pats collected from feedlot pen floors on subsequent E. coli O157 prevalence on carcasses at various points in the slaughter process. Fecal pats from the feedlot pen floor were collected within 3 days before slaughter. During cattle processing at the slaughter facility, additional samples were collected from the hide, from the colon, and from the carcasses before and after evisceration and after final decontamination. Of 15 lots (a group of cattle from the same pen from a feedlot) sampled, 87% had at least one positive fecal pat from the feedlot floor, 47% had a positive hide sample, 73% had a positive colon/fecal sample, and 47% had a positive carcass sample preevisceration; however, only 8% of lots had a positive carcass sample postevisceration or after final intervention. Of the total samples tested (n = 1,328), 24.7, 14.7, 27.6, 10.1, 1.4, and 0.3% of fecal pats from the feedlot floor, hide, colon, preevisceration, postevisceration, and final intervention samples, respectively, were positive for E. coli O157. Pens with greater than 20% positive fecal pats from the feedlot floor had 25.5% hide, 51.4% colon, and 14.3, 2.9, and 0.7% carcass samples positive at preevisceration, at postevisceration, and after final intervention, respectively. However, fecal pats from feedlot floor samples that contained less than 20% positive fecal samples showed lower pathogen prevalence, with 5.0% hide, 7.5% colon, and 6.3, 0, and 0% carcass positive samples at preevisceration, postevisceration, and post-final intervention, respectively. Data from this study can be used as part of risk assessment processes in order to identify mitigation strategies to minimize prevalence of E. coli O157 on fresh beef carcasses.
进入屠宰场的牛身上大肠杆菌O157的携带率可能在10%至超过70%之间。本研究旨在确定从饲养场围栏地面采集的粪便样本中大肠杆菌O157携带率对屠宰过程中不同时间点胴体上大肠杆菌O157后续携带率的影响。在屠宰前3天内从饲养场围栏地面采集粪便样本。在屠宰场对牛进行加工处理期间，还从牛皮、结肠以及去内脏前后和最终消毒后的胴体上采集了额外的样本。在抽样的15个批次（来自饲养场同一围栏的一群牛）中，87%的批次饲养场地面至少有一份粪便样本呈阳性，47%的批次牛皮样本呈阳性，73%的批次结肠/粪便样本呈阳性，47%的批次去内脏前胴体样本呈阳性；然而，只有8%的批次去内脏后或最终处理后的胴体样本呈阳性。在所有检测样本（n = 1328）中，饲养场地面粪便样本、牛皮样本、结肠样本、去内脏前样本、去内脏后样本和最终处理后样本中大肠杆菌O157呈阳性的比例分别为24.7%、14.7%、27.6%、10.1%、1.4% 和0.3%。饲养场地面粪便样本阳性率超过20%的围栏中，去内脏前、去内脏后和最终处理后牛皮、结肠和胴体样本的阳性率分别为25.5%、51.4%和14.3%、2.9%、0.7%。然而，饲养场地面样本中粪便样本阳性率低于20%的，病原体携带率较低，去内脏前、去内脏后和最终处理后牛皮、结肠和胴体阳性样本的比例分别为5.0%、7.5%和6.3%、0%、0%。本研究的数据可作为风险评估过程的一部分，以确定减轻策略，将新鲜牛肉胴体上大肠杆菌O157的携带率降至最低。
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