Heller C E, Scanga J A, Sofos J N, Belk K E, Warren-Serna W, Bellinger G R, Bacon R T, Rossman M L, Smith G C
Center for Red Meat Safety, Colorado State University, Fort Collins, Colorado 80523-1171, USA.
J Food Prot. 2007 May;70(5):1174-80. doi: 10.4315/0362-028x-70.5.1174.
The prevalence of Escherichia coli O157:H7 on beef subprimal cuts intended for mechanical tenderization was evaluated. This evaluation was followed by the assessment of five antimicrobial interventions at minimizing the risk of transferring E. coli O157:H7 to the interior of inoculated subprimal cuts during blade tenderization (BT) or moisture enhancement (ME). Prevalence of E. coli O157:H7 on 1,014 uninoculated beef subprimals collected from six packing facilities was 0.2%. Outside round pieces inoculated with E. coli O157:H7 at 10(4) CFU/100 cm2 were treated with (i) no intervention, (ii) surface trimming, (iii) hot water (82 degrees C), (iv) warm 2.5% lactic acid (55 degrees C), (v) warm 5.0% lactic acid (55 degrees C), or (vi) 2% activated lactoferrin followed by warm 5.0% lactic acid (55 degrees C) and then submitted to BT or ME. Prevalence (n=196) of internalized (BT and ME) E. coli O157:H7 was 99%. Enumeration of E. coli 0157:H7 (n=192) revealed mean surface reductions of 0.93 to 1.10 log CFU/100 cm2 for all antimicrobial interventions. E. coli O157:H7 was detected on 3 of the 76 internal BT samples and 73 of the 76 internal ME samples. Internal ME samples with no intervention had significantly higher mean E. coli O157:H7 populations than did those internal samples treated with an intervention, but there were no significant differences in E. coli O157:H7 populations among internal BT samples. Results of this study demonstrate that the incidence of E. coli O157:H7 on the surface of beef subprimal cuts is low and that interventions applied before mechanical tenderization can effectively reduce the transfer of low concentrations of E. coli O157:H7 to the interior of beef subprimal cuts.
对用于机械嫩化的牛肉主要切块上大肠杆菌O157:H7的流行情况进行了评估。在此评估之后,又对五种抗菌干预措施进行了评估,以尽量降低在刀片嫩化(BT)或水分增强(ME)过程中将大肠杆菌O157:H7转移到接种的主要切块内部的风险。从六个包装厂收集的1014份未接种的牛肉主要切块中,大肠杆菌O157:H7的流行率为0.2%。用大肠杆菌O157:H7以10(4) CFU/100 cm2的浓度接种的外脊肉块,分别采用以下处理:(i)不进行干预;(ii)表面修整;(iii)热水(82摄氏度);(iv)温热的2.5%乳酸(55摄氏度);(v)温热的5.0%乳酸(55摄氏度);或(vi)2%活性乳铁蛋白,随后是温热的5.0%乳酸(55摄氏度),然后进行BT或ME。内化(BT和ME)的大肠杆菌O157:H7的流行率(n = 196)为99%。对大肠杆菌O157:H7(n = 192)的计数显示,所有抗菌干预措施使表面菌数平均减少0.93至1.10 log CFU/100 cm2。在76份内部BT样本中的3份以及76份内部ME样本中的73份中检测到了大肠杆菌O157:H7。未进行干预的内部ME样本中的大肠杆菌O157:H7平均菌数显著高于接受干预处理的内部样本,但内部BT样本中的大肠杆菌O157:H7菌数没有显著差异。本研究结果表明,牛肉主要切块表面的大肠杆菌O157:H7发生率较低,并且在机械嫩化之前应用的干预措施可以有效减少低浓度大肠杆菌O157:H7向牛肉主要切块内部的转移。